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$Synthesis and Characterization of High Refractive Index Lens Material$

Title: The Synthesis and Characterization of High Refractive Index Lens Material.
Creator: Su, Yue, Stiegman, Albert E., Van Winkle, David H., Kennemur, Justin Glenn, Latturner, Susan, Florida State University, College of Arts and Sciences, Department of Chemistry and...
Show moreSu, Yue, Stiegman, Albert E., Van Winkle, David H., Kennemur, Justin Glenn, Latturner, Susan, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: High refractive index polymer has always been one of the great interests for their potential in industrial applications. One of the important methods in achieving this goal is to create high cross-linking density network. Though thiol-ene reaction, multi-vinyl monomer and multi-ene monomer joint covalently to form a dense network structure. This dissertation discusses a fundamental way to develop high refractive index polymer through thiol-ebe polymerization. In the first part of this...
Show moreHigh refractive index polymer has always been one of the great interests for their potential in industrial applications. One of the important methods in achieving this goal is to create high cross-linking density network. Though thiol-ene reaction, multi-vinyl monomer and multi-ene monomer joint covalently to form a dense network structure. This dissertation discusses a fundamental way to develop high refractive index polymer through thiol-ebe polymerization. In the first part of this dissertation, multi-vinyl monomers and multi-thiol monomers were synthesized and mixed to make polymers using thermal initiation. Structural characterizations were performed using infrared and NMR. Thermal characterizations were performed using DSC, TGA and DMA. Optical properties like refractive indices and transmission were also measured. The results indicate that among all the phosphine polymers, PVSe-BDTH has the highest refractive index and it is among the highest refractive index organic polymer could achieve. It also has high storage modulus of several GPa. In addition to PVSe-BDTH, PVSe-EDTH is another good candidate though the introduction of EDTH made the material slightly softer. The second part of this dissertation discusses the effects of the introduction of several synthesized additives. An increasing weight percent of additives were added to the in the formation of PMMA polymer and their effects on refractive indices were examined. The third part of this dissertation discusses the positive influence of the introduction of computational method upon guiding the development of our materials. The refractive indices and densities of the previously synthesized monomers and polymers were calculated and compared with the experimental values and proved to be effective. Then the method was applied to several of our potential monomer and polymer targets, by comparing their relative refractive indices the compounds with better anticipated properties were synthesized. The experimental measurements indicate that our combination of method and basis set provide rather accurate prediction on both frequency-dependent polarizabilities and molecular volumes, therefore providing refractive indices and densities that fit our expectations. In addition to these, the calculation method can also predict IR and NMR peaks and provide possible explanation to unknown peaks. Overall, it is a useful tool in our studies in the early stages of product design and property predictions.
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Date Issued: 2019
Identifier: 2019_Summer_Su_fsu_0071E_15401
Format: Thesis

Title: Solid-State NMR Studies on Battery Materials.
Creator: Li, Xiang, Hu, Yan-yan, Zheng, Jianping, Marshall, Alan G. (Alan George), Zhu, Lei, Yu, Zhibin, Florida State University, College of Arts and Sciences, Department of Chemistry...
Show moreLi, Xiang, Hu, Yan-yan, Zheng, Jianping, Marshall, Alan G. (Alan George), Zhu, Lei, Yu, Zhibin, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: As society demand for energy continues to rise, advanced electrochemical energy storage technologies are needed to address the challenges associated with effectively using the rechargeable energy as the alternative source to fossil fuels. Various types of alkali-ion rechargeable batteries have attracted notable attentions. The specific capacity of these batteries is mainly limited by the cathode materials. Among them, Lithium ion batteries have the desirable combination of high energy density...
Show moreAs society demand for energy continues to rise, advanced electrochemical energy storage technologies are needed to address the challenges associated with effectively using the rechargeable energy as the alternative source to fossil fuels. Various types of alkali-ion rechargeable batteries have attracted notable attentions. The specific capacity of these batteries is mainly limited by the cathode materials. Among them, Lithium ion batteries have the desirable combination of high energy density and power density, making them the most popular energy storage technique in worldwide applications, such as in cell phone, electric cars. Extensive studies have been done to improve the specific capacity by searching for high energy-density cathode materials. The capacities of LIBs are limited by cathodes. Sodium-ion batteries (SIBs) are an emerging electrochemical energy storage technology that has high promise for electrical grid level energy storage. High capacity, long cycle life, and low cost cathode materials are very much desired for the development of high performance SIB systems. Sodium manganese oxides with different compositions and crystal structures have attracted much attention because of their high capacity and low cost. Nuclear Magnetic Resonance (NMR) is a powerful tool to determine the nuclear (Li, Na, O, etc) local structural environments.
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Date Issued: 2019
Identifier: 2019_Spring_Li_fsu_0071E_15019
Format: Thesis

Title: Investigations into Structure-Property Relationships of Novel Polymers Synthesized Primarily from Bio-Renewable Resources.
Creator: Kieber, Robert John, Kennemur, Justin Glenn, Alamo, Rufina G., Schlenoff, Joseph B., Miller, Brian G., Florida State University, College of Arts and Sciences, Department of...
Show moreKieber, Robert John, Kennemur, Justin Glenn, Alamo, Rufina G., Schlenoff, Joseph B., Miller, Brian G., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: This dissertation investigates the synthesis and characterization of polymers primarily derived from renewable biomass sources, along with the structure-property influences on material properties. One polymer that has garnered interest as a promising value-added material is poly(2-vinylfuran) (PVF), an analog to styrene (S) derived from hemicellulose. Previous reports have determined the sole effective polymerization method to be through an emulsion. Investigations into this peculiar...
Show moreThis dissertation investigates the synthesis and characterization of polymers primarily derived from renewable biomass sources, along with the structure-property influences on material properties. One polymer that has garnered interest as a promising value-added material is poly(2-vinylfuran) (PVF), an analog to styrene (S) derived from hemicellulose. Previous reports have determined the sole effective polymerization method to be through an emulsion. Investigations into this peculiar observation herein determined that compartmentalization of the propagating chains allows for radical propagation, which was found to be an order of magnitude faster than for styrene. Further analysis of kinetics and material properties of the resulting polymers were investigated. In an alternate thrust, biomass derived isohexides were studied in detail to determine the influence of the inherent stereocenters on resulting polymer properties. Novel polyurethanes were synthesized from isosorbide (IS) and isomannide (IM) derived diisocyanates, as well as 2,5-bishydroxymethylfuran (BHMF) in varying feed ratios. It was concluded that the difference in stereochemistry significantly influenced chain behavior and the presence of entanglements, contributing significantly to the observed mechanical behavior. In an alternate thrust, the reactivity differences of the two chiral alcohols on IS were utilized to synthesize various asymmetric monomers capable of chain growth polymerizations. The resulting polymers were of significantly higher molecular weight and showed interesting thermal behavior due to the rigidity of the isohexide core. An additional investigation was conducted into the mechanical and viscoelastic properties of poly(4-phenylcylcopentene) (P4PCP) and its hydrogenated counterpart (H2-P4PCP), which is a novel ethylene-styrene (ES) copolymer analog previously synthesized in our lab. Both polymers were found to be quite ductile with glasstomeric behavior due to the proximity of the Tg to room temperature (~17 °C). Both polymers were found to have quite high elastic recovery and polymer creep, indicating the greater contribution of viscous behavior to the overall polymers. The precise arrangement of styrene (S) units along the backbone along with the lack of atactic polystyrene (PS) homopolymers was found to significantly influence material properties compared to previously synthesized ES copolymers.
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Date Issued: 2019
Identifier: 2019_Spring_KieberIII_fsu_0071E_15060
Format: Thesis

Title: Ring Opening Metathesis Polymerization of Low Ring Strain Species.
Creator: Neary, William James, Kennemur, Justin Glenn, Alamo, Rufina G., Alabugin, Igor V., Smith, Joel M., Florida State University, College of Arts and Sciences, Department of...
Show moreNeary, William James, Kennemur, Justin Glenn, Alamo, Rufina G., Alabugin, Igor V., Smith, Joel M., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: The ring opening metathesis polymerization of cyclopentene has been historically challenging due to the low ring strain nature of the cyclic olefin. Due to these challenges, the ROMP of this unique monomer has been overlooked for many years. We aim to shine light on this material and hopefully highlight its synthetic utility in areas that lack synthetic diversity in this thesis. We began our adventure on the ROMP of cyclopentenes with the investigation of 4-phenylcyclopentene. The polymers...
Show moreThe ring opening metathesis polymerization of cyclopentene has been historically challenging due to the low ring strain nature of the cyclic olefin. Due to these challenges, the ROMP of this unique monomer has been overlooked for many years. We aim to shine light on this material and hopefully highlight its synthetic utility in areas that lack synthetic diversity in this thesis. We began our adventure on the ROMP of cyclopentenes with the investigation of 4-phenylcyclopentene. The polymers produced from this monomer upon hydrogenation produced a precision ethylene-styrene copolymer with a phenyl on every 5th carbon backbone equating to a material with 71.2% styrene (w/w). Not only was this an area where single-site catalyst struggled, but this was the first time these polymers were produced in a precise manner. These materials lead our group to many other investigations such as investigations on its mechanical properties, post-polymerization modifications, and also a handful of collaborations. While this material brought a new interest of precision based materials to the Kennemur lab and laid one of the core foundations of our labs, it did leave some things to be desired, notably, the control of this polymerization process. Our emerging interest in this polymer quickly led us to find that controlling the polymerizations of cyclopentene based monomers using ruthenium based catalyst were problematic. With no system in place to control polymerizations, our group came up with a new methodology that utilizes cyclopentenes low ring strain and common thermodynamic principles to control the polymerizations. In this new methodology, termed variable temperature-ROMP, the simple variation of reaction temperature allowed for total control over the polymerization process for the first time. With this new methodology in hand, we aimed to synthesize complex architectures in which the newly formed precision materials were needed. The first structures we targeted were bottlebrush polymers. The successful polymerizations produced precision grafted polymers with grafts on every fifth backbone carbon, similar to the most common bottlebrush structures, poly(norbornene)s. This account was our first success in the realm of precision complex architectures, and hopefully many more architectures using these materials and the definitive correlation of structure to material properties will ensue. Out of all of experiments a graduate student imagines when joining a polymer lab, depolymerizing ones precious polymer back into starting material is the last thing they imagine. However, the unique topology of polypentenamers made this imagination a reality. Realizing that bottlebrush polymers produced from polypentenamers depolymerize in a unzipping mechanism unlocked a lot of possibilities for the future of this lab. This thesis will discuss in detail all of the success of polypentenamers in the Kennemur lab over the years and current work aimed to better understand these materials.
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Date Issued: 2019
Identifier: 2019_Spring_Neary_fsu_0071E_15084
Format: Thesis

Title: Application of Organic Synthesis to the Development of New Imaging Tools for Fluorescence Microscopy.
Creator: Macias Contreras, Miguel Angel, Zhu, Lei, Piekarewicz, Jorge, Hanson, Kenneth G., Miller, Brian G., Florida State University, College of Arts and Sciences, Department of...
Show moreMacias Contreras, Miguel Angel, Zhu, Lei, Piekarewicz, Jorge, Hanson, Kenneth G., Miller, Brian G., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: This dissertation consists of six chapters. Chapter one gives to the reader a brief introduction to several key concepts and backgrounds such as the relevance of zinc(II) ions in biology, the definition of small molecular probes and the development of protein tags, including the SNAP-tag technology, and bioorthogonal reactions for specific labeling of targets of interest. Chapter two is focused on the synthesis of small molecular probes for selective detection of zinc(II) ions. The rationale...
Show moreThis dissertation consists of six chapters. Chapter one gives to the reader a brief introduction to several key concepts and backgrounds such as the relevance of zinc(II) ions in biology, the definition of small molecular probes and the development of protein tags, including the SNAP-tag technology, and bioorthogonal reactions for specific labeling of targets of interest. Chapter two is focused on the synthesis of small molecular probes for selective detection of zinc(II) ions. The rationale behind their chemical structures involves (1) using a 7-dimethylaminocoumrin derivative as a fluorophore with good absorbance at 405 nm and (2) subtle modification of chemical structure to tune binding affinity. A family of three sensors was synthesized and their photophysical characterization was conducted in both organic and aqueous solutions. One of the sensors has a binding affinitity towards zinc(II) in the nanomolar range, which is relevant to certain organelles where the zinc(II) concentration is believed to be in that range. All sensors were used to image low and high concentration of zinc(II) ions in live HeLa cells. Chapter three shows how a small molecular probe was evolved into a substrate for the self-labeling enzyme SNAP-tag. The replacement of the benzyl ring in a O6-benzylguanine (BG) derivative with a pyridyl ring generated a new class of compounds, O6-(5-pyridylmethyl)guanine (5PG). 5PG derivatives were shown to be taken up by the enzyme, demonstrating its substrate ambiguity. A fluorescent 5PG derivative was employed to selectively label intracellular compartments such as nuclear envelope, actin fibers, lysosomes and Golgi apparatus. The pyridine ring was introduced with the purpose of forming part of a tetradentate ligand for zinc(II); thus, making the pyridine an integral part of a coordination motif and not only an spectator group. Such unique situation enabled the imaging of low and high concentrations of zinc at precise locations. Chapter four focusses on the development of SNAP-tag substrates for intracellular bioorthogonal labeling. A series of BG derivatives carrying reactive handles such as azides and strained alkenes was synthesized. The occurrence of strain promoted azide-alkyne cycloaddition (SPAAC) and inverse electron demand Diels-Alder (IED-DA) reaction inside cells was demonstrated using fluorescence microscopy. By introducing first a reactive handle via SNAP-tag, followed by the reaction with a suitable fluorophore, two intracellular targets –nuclear envelope and actin fibers –were specifically labeled. But the real novelty of this work is the concurrent dual labeling inside live HeLa cells. To demonstrate the feasibility of the simultaneous labeling of two protein targets the orthogonal pairs SNAP/CLIP and SPAAC/IED-DA were used. Two-color fluorescent microscopic images showed the orthogonality of the two pairs. In one experiment, the nuclear envelope was labeled with a green dye via CLIP-IED-DA and the actin fibers through SNAP-SPAAC. In a second experiment, the targets were reversed and the correct labeling was found, proving the specificity and flexibility of the method. Chapter five is divided in three sections and is intended to show the results that were not included in Chapters two, three and four but that were significant to the completion of the projects associated with those chapters. The first section is focused on the synthesis of a small molecular probe complementary to the ones described in Chapter two. After trying different synthetic strategies, such a compound could not be made. The second section describes the synthetic journey that was travelled to obtain a chelating azide containing 5PG derivative. Several strategies were followed but eventually it was shown that a bifunctional pyridine derivative carrying alcohol and acetal functionalities was the key intermediate needed to obtain the target compound. Two other BG derivatives with chelating azide functionality were also prepared. The third section focusses on the application of the azido-containing BG derivatives in the bioorthogonal labeling of live and fixed cells. The copper-catalyzed azide-alkyne cycloaddition (CuAAC) mediated labeling was not possible in living cells but it was made available in fixed cells. Fixed cells were labeled at concentrations as low 25 μM Cu(II) and with or without the use of an auxiliary ligand, showing the superiority of chelating azides versus regular azides. Chapter six concludes the work presented in the entire document.
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Date Issued: 2019
Identifier: 2019_Spring_MaciasContreras_fsu_0071E_14999
Format: Thesis

Title: Solid-State NMR and MRI Studies of Structure-Property Correlations in Fast Li/Na-Ion Conductors.
Creator: Chien, Po-Hsiu, Hu, Yan-yan, Siegrist, Theo, Shatruk, Mykhailo, Latturner, Susan, Gan, Zhehong, Florida State University, College of Arts and Sciences, Department of Chemistry...
Show moreChien, Po-Hsiu, Hu, Yan-yan, Siegrist, Theo, Shatruk, Mykhailo, Latturner, Susan, Gan, Zhehong, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: This doctoral thesis encompasses wide expanses of studies, which aim to advance the understanding of structure-property relationships in fast ion conductors (FICs) with a variety of characterization tools. In particular, powder X-ray diffraction (PXRD), electrochemical impedance spectroscopy (EIS), solid-state nuclear magnetic resonance (NMR), and magnetic resonance imaging (MRI) are jointly utilized to gain multidimensional knowledge. Two classes of FICs are examined and they are crystalline...
Show moreThis doctoral thesis encompasses wide expanses of studies, which aim to advance the understanding of structure-property relationships in fast ion conductors (FICs) with a variety of characterization tools. In particular, powder X-ray diffraction (PXRD), electrochemical impedance spectroscopy (EIS), solid-state nuclear magnetic resonance (NMR), and magnetic resonance imaging (MRI) are jointly utilized to gain multidimensional knowledge. Two classes of FICs are examined and they are crystalline (Na x Sr 1−x SiO 3−0.5x , Li 7 La 3 Zr 2 O 12 , and Li 10 GeP 2 S 12 ) and glass-ceramic (Na 3−y PS 4−x Cl x and Li 10 P 3 S 12 I) materials. In regard to properties, we focus on ionic conductivity, chemical phase compositions, lithium distribution, and local chemical environments. In this thesis, the structure-property relationships are explored from two aspects: fundamental and practical. Fundamentally, we firstly establish the correlation of chemical phase evolution with ionic conductivity in Na x Sr 1−x SiO 3−0.5x and prove that the origin of conductivity is from Na + motions rather than O 2− . Then, it is found that the ionic conductivity can be improved by careful control of synthesis conditions. The improvement, on one hand, springs from the enhancement of functional defect site, which is associated with the creation of P 4+ in PS 4 3− tetrahedra in Na 3−y PS 4−x Cl x . On the other hand, the promotion of higher ionic conductivity is gained in Li 10 P 3 S 12 I by yielding high content of glassy phase with low activation energy at low temperature. Practically, we are attracted to the development of promising FICs and the chemical stability of FICs against polarizations in solid-state batteries cells. Propelled by the desire, we start with the laser-assisted magic-angle-spinning (LASMAS) probe to monitor phase evolution and ion dynamics in situ during materials synthesis. Model test on Li 7 La 3 Zr 2 O 12 identifies a compositionally similar phase, which also has comparable ion dynamics as verified by sequential T 1 measurements. Lastly, we use MRI to track the Li distribution in the bulk Li 7 La 3 Zr 2 O 12 and Li 10 GeP 2 S 12 , and at the electrolyte−Li interfaces under pristine, cycled, and short-circuit conditions. Different polarizations of Li concentration have witnessed different failing mechanisms in these two materials. Multinuclear ( 6,7 Li, 17 O, 23 Na, 29 Si, 31 P, and 127 I) solid-state NMR and advanced acquisition techniques are adapted to help with the assignment of local chemical environments.
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Date Issued: 2019
Identifier: 2019_Spring_Chien_fsu_0071E_14993
Format: Thesis

Title: Harnessing Molecular Photon Upconversion with Self-Assembled Multilayers.
Creator: Dilbeck, Tristan, Hanson, Kenneth G., Oates, William, Strouse, Geoffrey F., Zhu, Lei, Florida State University, College of Arts and Sciences, Department of Chemistry and...
Show moreDilbeck, Tristan, Hanson, Kenneth G., Oates, William, Strouse, Geoffrey F., Zhu, Lei, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Molecular photon upconversion via triplet−triplet annihilation (TTA-UC) combines two or more low energy photons to generate a higher energy excited state. It is an emerging strategy to potentially increase maximum solar cell efficiencies from 33% to greater than 43%, surpassing the Shockley-Queisser limit. In this dissertation, we introduce self-assembled bilayers on high surface area metal oxide films as a strategy to facilitate TTA-UC. Due to its modular nature, this formation strategy...
Show moreMolecular photon upconversion via triplet−triplet annihilation (TTA-UC) combines two or more low energy photons to generate a higher energy excited state. It is an emerging strategy to potentially increase maximum solar cell efficiencies from 33% to greater than 43%, surpassing the Shockley-Queisser limit. In this dissertation, we introduce self-assembled bilayers on high surface area metal oxide films as a strategy to facilitate TTA-UC. Due to its modular nature, this formation strategy offers unique geometric and spatial control of donor−acceptor interactions at an interface. In Chapter 3, we discuss the use of self-assembled bilayers of acceptor and sensitizer molecules on high surface area metal oxides as a means of facilitating TTA-UC emission and generating an integrated TTA-UC dye-sensitized solar cell. The bilayer films generate photocurrent by two different mechanisms: (1) direct excitation and electron injection from the acceptor molecule and (2) low-energy light absorption by the sensitizer molecule followed by TTA-UC and electron injection from the acceptor upconverted state, as evidenced by intensity dependence and IPCE measurements. We also compare the energy transfer and photocurrent generation efficiency of the bilayer to a heterogeneous system, confirming the superior design of the bilayer structure. In Chapter 4, we explore the hypothesized mechanism for TTA-UC in a bilayer film. Steady-state and time-resolved emission/absorption spectroscopy were used to determine the rate constants of the processes involved. The rate constants indicate that sensitizer to acceptor triplet energy transfer as well as sensitizer and acceptor nonradiative decay rates are the primary efficiency limiting processes for TTA-UC at the interface. This information can help to guide the design of new self-assembled UC films, a critical step toward the long-term goal of generating a practical UC solar cell. The low solar energy conversion efficiency of TTA-UC solar cells can be attributed, at least in part, to the relatively narrow absorption features of the sensitizer molecule. In Chapter 5, we incorporate multiple sensitizers into a TTA-UC DSSC using bilayer and trilayer self-assembly to increase broadband light absorption. The sensitizers' work cooperatively to achieve peak TTA-UC efficiency at sub-solar irradiance (<1 sun or <100 mW cm2). The trilayer device exhibits a high efficiency of 1.2 x10-3%, nearing device relevance, due to the high sensitizer density and energy transfer cascade towards the charge separation interface. In conclusion, we outline improvements that must be made to produce a viable TTA-UC solar cell that can surpass the Shockley-Queisser limit. These improvements include engineering strategies, changing the sensitizer and acceptor, finding more effective redox mediators, understanding the structure of the bilayer film, and more. Efficient TTA-UC and photocurrent generation have the potential to increase the efficiency of existing record solar cells by more than 1%.
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Date Issued: 2019
Identifier: 2019_Spring_Dilbeck_fsu_0071E_15045
Format: Thesis

Title: N-Heterocyclic Carbene Copper Complexes: Catalysis and Coordination Chemistry.
Creator: Jo, Minyoung, Shatruk, Mykhailo, Locke, Bruce R., Miller, Brian G., Hanson, Kenneth G., Florida State University, College of Arts and Sciences, Department of Chemistry and...
Show moreJo, Minyoung, Shatruk, Mykhailo, Locke, Bruce R., Miller, Brian G., Hanson, Kenneth G., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: N-heterocyclic carbene (NHC) transition metal complexes have emerged as an important class of compounds in catalysis and coordination chemistry. As shown in Chapter 1 of this thesis, the strong σ-donating and weak π-accepting ability of NHC ligands, combined with sterically demanding substituents, enable the NHC-metal complexes to exhibit high chemical and thermal stability, consequently leading to good catalytic activity. NHCs with expanded rings, in particular, have been found to exhibit...
Show moreN-heterocyclic carbene (NHC) transition metal complexes have emerged as an important class of compounds in catalysis and coordination chemistry. As shown in Chapter 1 of this thesis, the strong σ-donating and weak π-accepting ability of NHC ligands, combined with sterically demanding substituents, enable the NHC-metal complexes to exhibit high chemical and thermal stability, consequently leading to good catalytic activity. NHCs with expanded rings, in particular, have been found to exhibit distinct electronic and steric character, which contributes to improving the catalytic efficiencies in the transition metal system. Ring-expanded NHCs are considered to be stronger electron donors and more sterically demanding ligands as compared to the classical 5-membered NHCs. These changes in the ligand’s character are caused by the additional methylene groups on the ring backbone and the enlarged N-C-N angle at the carbene center. Taking into account such appealing properties of the 6-membered NHCs, we have developed Cu(I) complexes bearing fused cyclic 6-membered NHC rings which exhibit superior activities in asymmetric allylic substitutions, which are described in Chapter 3. The highest regio- and enantioselectivity were achieved especially when the unusual aryl ether substrates were involved in the reactions mediated by the 6-NHC-Cu(I) catalysts. To find a rationale for such unconventional reactivities and better discern the reaction pathway, the systematic investigation has been conducted with complexes incorporating varied NHC ligands, substrates with different leaving groups, and various alcohol additives, all of which are expected to have a substantial impact in the catalytic cycle. Variation of the NHC ligands in the Cu-catalyzed allylic borylation with the aryl ether substrate showed different reaction rates depending on the NHC structure, where 6-NHC led to the full conversion within 9 h, as opposed to 5- and 7-membered NHCs which showed incomplete reactions even after 48 h. The leaving group of the substrate was significantly related to the product selectivity, as poor leaving groups, such as aryl ether and carbonate, induced high regio- and enantioselectivity compared to the good leaving groups, like bromide and mesylate, which gave rise to reduced selectivities. Recognizing the increased reaction rate by using alcohol additives, methanol and ethanol were found to promote the highest rates in our 6-NHC-Cu-catalyzed reactions, in contrast to bulky alcohols, which showed slower reaction rates. This result supports our hypothesis of the rate-determining 6-membered alcohol-involving transition state, the formation of which is sensitive to steric congestion. This study demonstrates that matching leaving group and catalyst is important to design the reaction, and when it comes to our NHC-Cu catalysts, the perfect paring of the extended aromatic 6-NHC ligand with the aromatic leaving groups provides an optimal catalytic system to reach the highest reaction rate and stereochemical outcomes. In terms of the coordination chemistry of NHC-Cu(I) complexes, these closed-shell Lewis-acidic moieties are considered to be suitable for reactions with main-group clusters to provide exceptional stability and increased solubility to the resulting assemblies, allowing their further modification through the solution chemistry. With this point in mind, in Chapter 4 we demonstrate the use of polyphosphide clusters as ligands in NHC-Cu complexes. Treatment of (TMS)3P7 (TMS = trimethylsilyl) with the NHC-CuCl gave rise to the large anionic bimetallic cluster, [NHC-Cu-P7(TMS)]–, crystalized as the [NHC-Cu-NHC]+ salt. Its crystal structure reveals that [(TMS)P7]2– is bound to the Cu(I) center via the η4 coordination mode, which leads to a slight distortion from the original nortricyclane-like structure. The reaction with the gold analogue delivered the fully-substituted neutral molecule, (NHC-Au)3P7, retaining the geometry and symmetry of the initial cage. In contrast to the original (TMS)3P7 cluster, these complexes show improved stability and solubility, being soluble in less polar solvents. Finally, in Chapter 5, we demonstrate a new solution-phase methodology to convert the elemental red phosphorus into polyphosphide clusters, which indeed prompted the investigation of their reactivities described in the preceding chapter. A reaction between red phosphorus and potassium ethoxide in THF/DME yielded a mixture of soluble polyphosphide species containing P162–, P213–, and P5–. The use of such mild reactants offers the ease of red phosphorus activation to improve the accessibility to the polyphosphide species, which was not readily achieved by the conventional methods using strongly reducing reactants. The reaction outcome is governed by the choice of solvent, particularly by the boiling points and polarity, since the boiling point determines the activation temperature, and the polarity seems to be related to the stabilization of the resulting polyphosphide clusters. Other potential activators such as thiolates were examined, giving rise to only P162– species selectively, which suggests that the activation proceeds via a redox mechanism, in contrast to the nucleophilic activation with alkali metal alkoxides.
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Date Issued: 2019
Identifier: 2019_Spring_Jo_fsu_0071E_15114
Format: Thesis

Title: Search for Electrically Ordered Phases in Hydrogen-Bonded Molecular Cocrystals.
Creator: Lengyel, Jeffrey William, Dalal, Naresh S., Shatruk, Mykhailo, Hill, S. (Stephen Olof), Albrecht-Schmitt, Thomas E., Florida State University, College of Arts and Sciences,...
Show moreLengyel, Jeffrey William, Dalal, Naresh S., Shatruk, Mykhailo, Hill, S. (Stephen Olof), Albrecht-Schmitt, Thomas E., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Hydrogen bonds are an important type of non-covalent bonding intermolecular interactions with many applications in the design of molecular materials for pharmaceuticals and organic electronics. Due to the relative strength of hydrogen bonds when compared to other intermolecular interactions, the crystal packing of molecular materials is highly influenced by their presence. The strength of hydrogen bonds in cocrystals of two molecular components correlates to the difference in pKa values of...
Show moreHydrogen bonds are an important type of non-covalent bonding intermolecular interactions with many applications in the design of molecular materials for pharmaceuticals and organic electronics. Due to the relative strength of hydrogen bonds when compared to other intermolecular interactions, the crystal packing of molecular materials is highly influenced by their presence. The strength of hydrogen bonds in cocrystals of two molecular components correlates to the difference in pKa values of the components, following an empirical trend known as the “ΔpKa rule”. In some cases where ΔpKa is small, the proton composing the hydrogen bond can be transferred between acid and base reversibly. Due to the inherent dipole in asymmetric hydrogen bonds, reversible proton transfer may give rise to a reversible polarization necessary to achieve ferroelectricity. In this work we have constructed a database of organic acids and bases with their associated pKa values in order to explore possible two component combinations to achieve functionalized proton transfer. The database of synthons with pKa values was organized into a matrix of ΔpKa values for each combination. Several of these combinations with small ΔpKa values were synthesized and crystals were grown and characterized, primarily through single-crystal X-ray diffraction. From the resulting structures a few common packing motifs were identified. One combination, the hydrated salt of squaric acid and 2,3-dimethylpyrazine, was identified as an antiferroelectric with a phase transition at 104 K. The mechanism of this phase transition was investigated through powder X-ray diffraction, single-crystal neutron diffraction, Raman spectroscopy, heat capacity, and dielectric measurements. Besides reversible proton transfer, hydrogen bonds may also be used to template supramolecular structures. Thiourea can form 1-D hexagonal channels around guest molecules. Due to the variable strength of the hydrogen bond, the diameter of these channels is dependent on the size and shape of the guest molecule. To explore the effects of this templating on the guest molecules properties we synthesized cocrystals of thiourea with the magnetic radical molecules TEMPO and 4-oxo-TEMPO.
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Date Issued: 2019
Identifier: 2019_Spring_Lengyel_fsu_0071E_15156
Format: Thesis

Title: Investigating Oligomerization as a Form of Enzyme Regulation in Human Glucokinase.
Creator: McCray, Malcolm M. R. K. (Malcolm Marvin Rufus Kenyatta), Miller, Brian G., Zhu, Lei, Roper, Michael Gabriel, Stagg, Scott, Florida State University, College of Arts and...
Show moreMcCray, Malcolm M. R. K. (Malcolm Marvin Rufus Kenyatta), Miller, Brian G., Zhu, Lei, Roper, Michael Gabriel, Stagg, Scott, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Recent studies have shown the importance of enzyme regulation through the formation of higher order structures. This is exemplified by Acetyl coenzyme A Carboxylase, and Cytidine Triphosphate synthase, two enzymes that form long chain filaments in the presence of specific activators [5-7,14,22,26]. Recently, yeast glucokinase (Glk1p) was found to form filaments in the presence of increasing concentrations of Glucose-6-phosphate (G6P), the product of the reaction that it catalyzes [18]. Due to...
Show moreRecent studies have shown the importance of enzyme regulation through the formation of higher order structures. This is exemplified by Acetyl coenzyme A Carboxylase, and Cytidine Triphosphate synthase, two enzymes that form long chain filaments in the presence of specific activators [5-7,14,22,26]. Recently, yeast glucokinase (Glk1p) was found to form filaments in the presence of increasing concentrations of Glucose-6-phosphate (G6P), the product of the reaction that it catalyzes [18]. Due to this fact, and the consistent appearance of what seem to be higher order and oligomer like peaks in size exclusion chromatography (SEC) chromatograms of human glucokinase (GK) expressed from Escherichia coli, an investigation of the nature of these peaks was conducted. Through the use of SEC, a method described in Tayyab at al 1992 was used to determine the molecular weight [38]. This resulted in the discovery that only the oligomeric peak was formed over time, was the approximate size of a trimeric glucokinase structure. SEC also discovered that factors, including time and ligand presence, affected the formation of the oligomeric complex, while spectrophotometric assays of the oligomeric protein indicated a decrease in overall activity. The oligomeric form of GK produced little to no activity in the presence of increasing concentrations of its substrate, glucose. This finding is consistent with the fact that the oligomer is an inactive form of GK that is not affected by glucose concentrations.
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Date Issued: 2019
Identifier: 2019_Spring_McCray_fsu_0071N_15200
Format: Thesis

Title: Development and Application of the Variational Two-Electron Reduced Density Matrix Complete Active Space Self-Consistent Field Method to Address the Electron Correlation Problem in Quantum Chemistry.
Creator: Maradzike, Elvis, DePrince, A. Eugene, Bertram, R. (Richard), Steinbock, Oliver, Yang, Wei, Florida State University, College of Arts and Sciences, Department of Chemistry and...
Show moreMaradzike, Elvis, DePrince, A. Eugene, Bertram, R. (Richard), Steinbock, Oliver, Yang, Wei, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: The goal of this dissertation is to describe a series of developments and applications of the variational two-electron reduced density matrix (v2RDM-) complete active space self-consistent field (CASSCF) method to the electron correlation problem in electronic structure theory. The v2RDM-CASSCF method is a complete active space (CAS) method based on optimizing the two-electron reduced density matrix (2RDM). Since the 2RDM is a more compact object than the N-electron wavefunction, it is...
Show moreThe goal of this dissertation is to describe a series of developments and applications of the variational two-electron reduced density matrix (v2RDM-) complete active space self-consistent field (CASSCF) method to the electron correlation problem in electronic structure theory. The v2RDM-CASSCF method is a complete active space (CAS) method based on optimizing the two-electron reduced density matrix (2RDM). Since the 2RDM is a more compact object than the N-electron wavefunction, it is possible to formulate a CAS approach that scales polynomially, rather than exponentially, with respect to the size of the active space. For this reason, computer implementations of v2RDM-driven CASSCF are capable of treating active spaces much larger than the limit of current implementations of wavefunction-/configuration interaction (CI-) driven wavefunction CASSCF. The work described in this dissertation addresses three deficiencies of v2RDM-CASSCF: the lack of an analytic energy derivative code, the lack of an efficient code with which to compute excited states, and the lack of a method with which to correct the v2RDM-CASSCF energy for dynamical correlation. We develop analytic first derivatives of the v2RDM-CASSCF energy, and we show, in fact, that the expressions for the analytic first derivative of the energy are identical to those for CI-based CASSCF. For the excited state problem, we improve an approach by which excited states and excited state properties can be computed from the ground state 2RDM. Lastly, we develop a model for dynamical correlation for v2RDM-CASSCF references. With this model, energies computed at the v2RDM-CASSCF level of theory can be corrected to account for the effects of dynamical correlation.
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Date Issued: 2019
Identifier: 2019_Summer_Maradzike_fsu_0071E_15349
Format: Thesis

Title: Intermetallic Carbides, Borides, and Carbide Hydrides from Re/Ni Fluxes (Re = La, Pr).
Creator: Engstrand, Tate O. (Tate Owen), Latturner, Susan, Siegrist, Theo, Albrecht-Schmitt, Thomas E., Stiegman, Albert E., Florida State University, College of Arts and Sciences,...
Show moreEngstrand, Tate O. (Tate Owen), Latturner, Susan, Siegrist, Theo, Albrecht-Schmitt, Thomas E., Stiegman, Albert E., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Metal flux synthesis is a useful technique for the discovery of novel intermetallic phases. The molten state enhances diffusion rates which improves rates of reaction. Reactions can proceed at lower temperatures, allowing for the observation of metastable phases. The technique also allows favorable conditions for single crystal growth. In this work, two mixed metal fluxes were explored. The first was a Pr/Ni binary mixture in a 3:1 ratio, melting at a temperature of 525 °C. The mixture acted...
Show moreMetal flux synthesis is a useful technique for the discovery of novel intermetallic phases. The molten state enhances diffusion rates which improves rates of reaction. Reactions can proceed at lower temperatures, allowing for the observation of metastable phases. The technique also allows favorable conditions for single crystal growth. In this work, two mixed metal fluxes were explored. The first was a Pr/Ni binary mixture in a 3:1 ratio, melting at a temperature of 525 °C. The mixture acted as a solvent for iron and other transition metals to react with main group elements. The second was a binary La/Ni eutectic 67% rich in lanthanum, m.p. 517 °C. This latter flux was used to grow an intermetallic carbide using anthracene as a reactant. Reactions of silicon and phosphorus with iron and carbon in the Pr/Ni binary mixture produced phases of the new structure type Pr62Fe21M16C32 (M = Si, P) in the P4/mmm space group (a = 15.584(2) Å, c = 11.330(1) Å for the Si analog). These compounds have a zeolite-like iron carbide framework of corner-sharing FeC3 subunits filled with a cationic Pr/M network. Building blocks in the structure were found to be in common with those in Pr21Fe8Si7C12, a new analog of the previously reported La21Fe8Sn7C12. Magnetic susceptibility measurements and band structure calculations for Pr62Fe21Si16C32 indicate that the iron atoms in the compound are not magnetic; the low temperature complex antiferromagnetic ordering is due to the Pr3+ ions. Conversely, both iron and praseodymium moments contribute to the magnetic behavior of Pr21Fe8Si7C12. Pr/Ni flux reactions with tellurium, iron and boron resulted in the intermetallic phase with new structure type Pr21Fe16Te6B30 in the cubic space group P-43m (a = 10.61709 Å). Initially, the phase appeared to grow in the Pm-3m space group, but bond length analysis indicated the growth of the phase was subject to twinning. The P-43m local structure was verified by TEM measurements. The phase features Fe16B30 clusters composed of an Fe16 Friauf polyhedron surrounded by a complex network of boron atoms. Adjacent Fe16B30 clusters are bridged by boron-boron dimers and are surrounded by a cationic Pr/Te network. Both the praseodymium ions and the iron contribute to the effective magnetic moment of this compound. Reactions of iron and anthracene in a La/Ni flux produced the new metal carbide La15(FeC6)4H. Anthracene acts as a carbon and hydrogen source. The presence of hydride in the product was indicated by single crystal X-ray diffraction and probed by 1H MAS NMR.
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Date Issued: 2019
Identifier: 2019_Summer_Engstrand_fsu_0071E_15310
Format: Thesis

Title: Effects of Obesity-Related Inflammation on Breast Cancer Progression.
Creator: Vallega, Karin Andrea, Sang, Qing-Xiang, Ren, Yi, Fadool, Debra Ann, Stagg, Scott, Steinbock, Oliver, Florida State University, College of Arts and Sciences, Department of...
Show moreVallega, Karin Andrea, Sang, Qing-Xiang, Ren, Yi, Fadool, Debra Ann, Stagg, Scott, Steinbock, Oliver, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: In the United States, breast cancer is the most commonly diagnosed cancer in women, except for skin cancers. The American Cancer Society estimates there will be 268,600 new cases in 2019 alone. It is also the second leading cause of cancer mortality in U.S. women, after lung cancer, with an estimated 41,760 deaths set to occur in 2019. However, worldwide, breast cancer is the most frequently diagnosed cancer in women and the leading cause of female cancer deaths. There are many disparities in...
Show moreIn the United States, breast cancer is the most commonly diagnosed cancer in women, except for skin cancers. The American Cancer Society estimates there will be 268,600 new cases in 2019 alone. It is also the second leading cause of cancer mortality in U.S. women, after lung cancer, with an estimated 41,760 deaths set to occur in 2019. However, worldwide, breast cancer is the most frequently diagnosed cancer in women and the leading cause of female cancer deaths. There are many disparities in breast cancer incidence and prognosis. Among the starkest of these disparities is the difference between African American and Caucasian American women. African American women present with higher rates of aggressive triple-negative subtype, earlier age at diagnosis, and have a 39% higher mortality rate than Caucasian American women. African American women also have higher rates of obesity than Caucasian American women. Obesity and inflammation are also very closely linked to breast cancer. Obesity causes chronic inflammation, and is a risk factor for post-menopausal breast cancer and worse prognosis. This work looks at several effects of obesity-related inflammation in the progression of breast cancer. Bioinformatics was used to explore the differential expression of resistin, a pro-inflammatory cytokine that has 4-fold higher expression in African American women. Due to the pro-inflammatory behavior, and role in adipose tissue, resistin may be a link between obesity, inflammation, and cancer. Resistin was differentially expressed in African American early-stage receptor negative subtypes. It was especially linked to estrogen receptor negative breast cancer subtype. Resistin expression was also higher in triple-negative subtype compared to luminal A subtype, which is hormone receptor positive. The high levels of resistin could contribute to African American breast cancer phenotype and high mortality rates. It may also serve as an early detection biomarker, since it is linked to early stages. Another effect of obesity that was analyzed in this work was the role of macrophages in breast cancer cell-adipocyte crosstalk. Obesity triggers increased infiltration of macrophages into adipose tissue. An innovative cell co-culture system was used to study the paracrine interactions between adipocytes, macrophages, and breast cancer cells, and how they can benefit tumor progression. Macrophage conditioned media intensified the effects of breast cancer cell-adipocyte crosstalk. In this crosstalk, adipocytes become cancer-associated, meaning they become delipidated and increase production of pro-inflammatory cytokines. Breast cancer cells then benefit from this increased inflammation and become more aggressive. Macrophage conditioned media in breast cancer cell and adipocyte co-culture increased tumor cell proliferation and migration compared to co-culture with nonconditioned media. Macrophage conditioned media also increased the expression of pro-inflammatory cytokines by adipocytes, even in the absence of breast cancer cells, although the expression levels were highest with all three cell components. Additionally, in co-culture of adipocytes and breast cancer cells with macrophage conditioned media, adipocytes showed signs of delipidation. Therefore, macrophages contribute to adipocyte inflammation and cancer-association, and help drive tumorigenesis.
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Date Issued: 2019
Identifier: 2019_Summer_Vallega_fsu_0071E_15362
Format: Thesis

Title: Photochemistry of Pyridazine N-Oxides: A Versatile Tool for Heterocycle Synthesis.
Creator: Borger, Maribel, Frederich, James H., Fajer, Piotr G., Saltiel, Jack, Miller, Brian G., Florida State University, College of Arts and Sciences, Department of Chemistry and...
Show moreBorger, Maribel, Frederich, James H., Fajer, Piotr G., Saltiel, Jack, Miller, Brian G., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Presently, green chemistry is a movement that proactively seeks to create alternative and earth-friendly processes. It is a growing field open for innovation and cost-effective measures to enrich the scientific community while catering to an increasing world population. A technique available to green chemistry is photochemistry. The use of light as a means of chemical change can offer energy saving solutions to chemical reactions performed in organic chemistry. 1,2-diazine N-oxides are bench...
Show morePresently, green chemistry is a movement that proactively seeks to create alternative and earth-friendly processes. It is a growing field open for innovation and cost-effective measures to enrich the scientific community while catering to an increasing world population. A technique available to green chemistry is photochemistry. The use of light as a means of chemical change can offer energy saving solutions to chemical reactions performed in organic chemistry. 1,2-diazine N-oxides are bench top stable starting materials rendering them useful building blocks for complex molecules. The photochemistry of pyridazine N-oxides has not been rigorously exploited because of the lack of efficient regioselective access and inability to control competitive reactions. They possess the potential for development of many reaction pathways, including ring-opening and photoreduction. During our investigations of the photochemical ring-opening, we observed an intermediate that is formed after exposure to UV light. To the best of our knowledge, this transient compound has not been isolated or heavily exploited for new reactions. Herein, I will describe our efforts to exploit this (Z)-diazoenone intermediate for applications in heterocycle synthesis using heat and transition metal catalysis The first strategic use of pyridazine N-oxide to nitrogen heterocycles is disclosed. Our synthesis began with readily available 3,6-dichloropyridazine N-oxide and a regioselective Suzuki-Miyaura cross-coupling with PdCl2dppf which selectively couples at C3. Furthermore, aromatic substitution (SNAr) reactions were amenable toward these electron deficient heterocycles to furnish a library of non-symmetric photosubstrates. Upon photolysis with UV light (hv= 350 nm) and elevated temperatures, photochemical ring opening was observed to provide elaborate pyrazole motifs. We varied the electronics of pyridazine N-oxides at C3 with electron withdrawing and electron donating aryl groups. C6 was functionalized with various nucleophiles including nitrogen, oxygen and sulfur. Additionally, we were able to demonstrate this method as a tool in synthesis in our first application to a target molecule. We found reaction conditions to distinguish between competitive ring opening reaction pathways (1) thermal cyclization to afford pyrazole and (2) formation of a π-excessive building block, 2-aminofuran. However, 2-aminofurans are labile and readily oxidize in air, rendering them buildings with obvious limitations. We report a method to synthesize 2-aminofurans using a combination of UV light and rhodium catalysis. These reactive intermediates are used in Diels-Alder cycloaddition reactions with alkenes to give entry to heterocyclic scaffolds found within natural products such as carbazoles and dibenzofurans. Our scope highlighted N-oxides with nucleophilic nitrogen and oxygen as an extension of the library of N-oxides used for pyrazole formation. Moreover, we harnessed the functionality of these scaffolds from synthetically accessible pyridazine N-oxides using our established regioselective approach to non-symmetric N-oxides. We were able to find dienophiles compatible with our system extending the groups incorporated into the carbazole skeletons. In our system, we found limitations and describe our efforts to rationalize our observations. In our quest of finding the synthetic utility of 2-aminofurans in Diels-Alder chemistry, we found 2-aminofurans harboring a nitrogen nucleophile in the ortho position of the aryl ring at C3, as introduceing new reactivity producing 1H-indole-2-acetamide. Indole scaffolds have a wide array of value in organic synthesis. Our strategy is to explore the acid-catalyzed isomerization of 2-aminofuran to functionalized indoles that would be difficult to make. Ring opening of heterocyclic N-oxides can be a powerful tool in organic synthesis. Key to our success was access to pyridazine N-oxides with functionality around the pyridazine nucleus that allowed for control of the competitive pathways.
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Date Issued: 2019
Identifier: 2019_Summer_Borger_fsu_0071E_15163
Format: Thesis

Title: Discovering the Phillips Catalyst: from Characterizing the Precursor to the Initiating Sites.
Creator: Peek, Nathan, Stiegman, Albert E., Telotte, John C., Shatruk, Mykhailo, Hu, Yan-yan, Florida State University, College of Arts and Sciences, Department of Chemistry and...
Show morePeek, Nathan, Stiegman, Albert E., Telotte, John C., Shatruk, Mykhailo, Hu, Yan-yan, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Our research aimed at exploiting spectroscopic techniques in order to characterize and determine the electronic and vibrational properties of chromium(VI) oxides (precursor to the Phillips catalyst) dispersed on an amorphous silica support for the sake of investigating the Phillips catalyst system. In addition to characterizing the Cr(VI)/SiO2 just mentioned, we focus on analyzing the mechanistic pathway the sites undertake to becoming catalytically active. Catalytic activation of the...
Show moreOur research aimed at exploiting spectroscopic techniques in order to characterize and determine the electronic and vibrational properties of chromium(VI) oxides (precursor to the Phillips catalyst) dispersed on an amorphous silica support for the sake of investigating the Phillips catalyst system. In addition to characterizing the Cr(VI)/SiO2 just mentioned, we focus on analyzing the mechanistic pathway the sites undertake to becoming catalytically active. Catalytic activation of the material involves a redox reaction with either carbon monoxide (CO) gas or ethylene (C2H4) gas to reduce the chromium to a labile, open-faced Cr(II)/Si. These highly reactive Cr(II) sites react with ethylene almost instantaneously to form the active sites for polymerization. An old sol-gel method previously developed for this system was used for the synthesis of our Cr(VI)/Si xerogel materials.17,18 These sol-gels provide higher quality spectroscopic resolution at lower concentrations and are isotropic and non-scattering which allows the use of polarization studies. These factors allow for a superior investigation through spectroscopy. Raman, resonance Raman, and low temperature fluorescent techniques were used for investigating the vibrational properties of the initial Cr(VI)/Si as well as the material after onset of polymerization. UV-Vis and fluorescent spectroscopy were used for analyzing the electronic properties of the initial Cr(VI) as well as studying the reduction of the chromium and polymerization via C2H4(g). In-situ electron paramagnetic resonance (EPR) assisted in analyzing the oxidation state of our chromium material during the different stages of the preparation and initiation. The electronic and vibrational modes of the Cr(VI)/Si precursor were assigned with the help of a collaborator from FSU whom performed computational studies We assign the electronic structure to a dioxoCr(VI) species with two terminal Cr=O bonds and two Cr-O-Si bridging networks. The possibility of other species claimed to potentially be present was tested and no spectroscopic evidence was observed for any species other than the dioxoCr. The Chromium is observed to reduce to Cr(II) through an intermediate Cr(IV) via CO reduction. It is then observed to oxidize to an organoCr(III)/Si after exposure to ethylene and formation of the active sites for polymerization. Reduction using ethylene is still less understood, but is hypothesized to go through the same oxidation states and is experimentally observed to be consistent with the CO method in terms of polymer produced and Cr(III) active sites. As to the type of Cr structure present after initiation, we identify the presence of a vinylCr(III) species and present a proposal for the mechanism of initiation for the Phillips catalyst.
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Date Issued: 2019
Identifier: 2019_Summer_Peek_fsu_0071E_15407
Format: Thesis

Title: Microfluidic-Enabled Quantitative Measurements of Insulin Release Dynamics from Single Pancreatic Islets of Langerhans.
Creator: Bandak, Basel, Roper, Michael Gabriel, Fajer, Piotr G., Bleiholder, Christian, Stagg, Scott, Florida State University, College of Arts and Sciences, Department of Chemistry and...
Show moreBandak, Basel, Roper, Michael Gabriel, Fajer, Piotr G., Bleiholder, Christian, Stagg, Scott, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: The work in this dissertation presents a microfluidic method for the quantitative measurement of insulin secretion rates and patterns from single pancreatic islets of Langerhans. Proper release of insulin from islets is essential for maintaining glucose homeostasis. For full efficacy, both the pattern and the amount of hormone release are critical. It is therefore important to understand how insulin levels are secreted from single islets in both a quantitative fashion and in a manner that...
Show moreThe work in this dissertation presents a microfluidic method for the quantitative measurement of insulin secretion rates and patterns from single pancreatic islets of Langerhans. Proper release of insulin from islets is essential for maintaining glucose homeostasis. For full efficacy, both the pattern and the amount of hormone release are critical. It is therefore important to understand how insulin levels are secreted from single islets in both a quantitative fashion and in a manner that resolves temporal dynamics. Although several systems have been described for high time resolution measurements, many are limited in their ability to quantify release. Previous microfluidic systems for single islet hormone secretion measurements used pressure-driven perfusion systems to deliver glucose solutions to an islet chamber and sampled secretions by electroosmotic flow (EOF). Because of a discrepancy in these flow rates, only a small fraction of the secretions was sampled. Experimental variables, such as islet proximity to the sampling channel, can alter that percentage, hindering islet-to-islet comparisons of insulin measurements. Using finite element analysis, a microfluidic system was designed that ensured cellular secretions were homogenized (RSDs < 3%) prior to sampling, permitting quantitative monitoring of insulin and examination of inter-islet biological variability. Using the new design, the system was tested with standard insulin solutions and demonstrated RSDs of < 2% as well as a detection limit of 10 nM insulin, low enough for single islet sampling. The application of this system to monitor insulin release from murine islets demonstrated biphasic secretory rates and dynamics that were in good agreement with other reports. Single islets from healthy and T2DM human donors were also sampled, and with this system, blunted phase 1 peaks and lower secretion rates were quantified in the diseased samples compared with the healthy donor samples. Chronically elevated levels of lipids have been associated with insulin resistance and impaired insulin secretion. Using this quantitative microfluidic system, the acute and chronic effects of two classes of lipids were investigated: palmitic acid, a free fatty acid (FFA), and 5-palmitic acid hydroxy stearic acid (5-PAHSA), which is a member of the novel fatty acid hydroxy fatty acid (FAHFA) class of lipids that are upregulated in non-diabetic individuals. Acute exposure of these two classes of lipids to islets induced elevated secretion rates, consistent with published reports. Chronic incubation (48-h) with 5-PAHSA significantly augmented glucose-stimulated insulin secretion (GSIS) rates and dynamics at the single islet level compared to chronic incubation without the lipid. Incubation in the presence of palmitic acid (PA) resulted in impaired insulin release, as characterized by lower release rates and the loss of pulsatility. The studies were continued in human islets from both healthy and type 2 diabetes mellitus (T2DM)-diagnosed donors. Total amounts of GSIS were not only augmented in islets that were chronically incubated with 5-PAHSA, but the dynamic insulin release profiles also improved as noted by more pronounced insulin oscillations. With this quantitative microfluidic system, the anti-diabetic effects of 5-PAHSA were corroborated by demonstrating improved islet function after chronic incubation with this lipid via improved oscillatory dynamics along with higher basal and peak release rates. It has been shown that cellular stress derived from reactive oxygen species (ROS) plays a critical role in the impairment and apoptosis of insulin secreting cells. A microfluidic analytical method has been developed that permits the simultaneous measurements of real-time oxidative stress dynamics with insulin release patterns from single murine islets in vitro. A redox-sensitive biosensor (Grx1-roGFP2) was virally delivered to islets of Langerhans and selectively expressed in β-cells. The ratiometric fluorescence output of the biosensor was utilized to image intracellular ROS dynamics in response to extracellular stimuli, simultaneously with insulin release patterns using a microfluidic dual microscopy system. Single islets were loaded on the microfluidic device and stimulated with 11 mM glucose while ROS and insulin levels were measured simultaneously. The resulting secretory profile of insulin was biphasic, in which the first phase response was observed with a duration of 5-10 min, followed by second phase oscillations with periods of 3-5 min. The biosensor fluorescence also exhibited similar dynamic profiles, with the fluorescence ratio rapidly increasing during first phase insulin release and showing pulsatility that was synchronized with insulin oscillations in second phase release. Dynamic stimulations of infected islets with 20 mM glucose from 11 mM levels also showed a dose-dependent response in the redox state of islet β-cells. These results suggest that ROS generation is associated with insulin release dynamics and highlight the potential role of ROS in insulin release signaling. The experimental method presented here is amenable to the quantitative examination of acute changes of other intracellular metabolites simultaneously with the release of other hormones.
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Date Issued: 2019
Identifier: 2019_Summer_Bandak_fsu_0071E_15312
Format: Thesis

Title: Cell Adhesion Behavior and Protein-Surface Interactions on Polyelectrolyte Multilayer Thin Films.
Creator: Surmaitis, Richard L., Schlenoff, Joseph B., Locke, Bruce R., Kennemur, Justin Glenn, Zhu, Lei, Florida State University, College of Arts and Sciences, Department of Chemistry...
Show moreSurmaitis, Richard L., Schlenoff, Joseph B., Locke, Bruce R., Kennemur, Justin Glenn, Zhu, Lei, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Polyelectrolyte multilayer thin films have been used as coatings due to their biocompatibility for cell culture experiments. During layer-by-layer assembly of these multilayer thin films, the film is altered by adjusting the salt concentration, the rinsing time, and the temperature which changes the morphology of the film. Certain factors such as surface charge and the polymer effect the biocompatibility of the film and its ability to adsorb serum proteins. If cells adhere and proliferate on...
Show morePolyelectrolyte multilayer thin films have been used as coatings due to their biocompatibility for cell culture experiments. During layer-by-layer assembly of these multilayer thin films, the film is altered by adjusting the salt concentration, the rinsing time, and the temperature which changes the morphology of the film. Certain factors such as surface charge and the polymer effect the biocompatibility of the film and its ability to adsorb serum proteins. If cells adhere and proliferate on a film it is called 'cytophilic'. Conversely, if cells do not adhere to a film or undergo apoptosis on the film, the surface is called 'cytophobic'. Cell behavior was discussed in this dissertation for polyelectrolyte multilayers composed of the polycations; poly(diallyldimethylammonium), PDADMAC, and poly(allylammonium chloride), PAH, and polyanions; poly(4-styrenesulfonic acid), PSS, and poly(acrylic acid), PAA. The adhesion and proliferation of cells are dependent on the surface to which they attach. Aside from cell counting, cell "health" on surfaces is typically established by measuring the metabolic rate with dyes that participate in the metabolic pathway or using "live/dead" assays with combinations of membrane permeable/impermeable dyes. Whether cells are attached or not, and whether they are living or dead, provides an incomplete picture of cell health. In this dissertation, proliferation rates and net metabolism of 3T3 fibroblasts seeded on "biocompatible" ultrathin polyelectrolyte multilayer films and on control tissue culture plastic were compared. Cells adhered to, and proliferated on, both surfaces, which were shown to be nontoxic according to live/dead assays. However, adhesion was poorer on the multilayer surface, illustrated by diffuse organization of the actin cytoskeleton and less-developed focal adhesions. Proliferation was also slower on the multilayer. When normalized for the total number of cells, it was shown that cells on multilayers experienced a five-day burst of metabolic stress, after which the metabolic rate approached that of the control surface. This initial state of high stress had not been reported previously in studies of cell growth on multilayers, although the observation period for this system was usually a few days. The interaction of nanoparticles and surfaces with the complex array of proteins in physiological media is largely responsible for maintaining circulation in the bloodstream and biocompatibility in general. It is known that composition of the initial "soft" corona of exchangeable adsorbed proteins evolves to comprise a more tenaciously held "hard" corona. In this dissertation, the dependence of cell adhesion on a thin film of polyelectrolyte complex is connected to the "hardness" of the initial corona using albumin, the most prevalent protein in serum. The ease with which albumin can be displaced depended on the surface functional group - carboxylate or sulfonate, in particular aromatic sulfonate. Carboxylate permitted easier exchange of albumin, which presumably allowed the adsorption of proteins such as fibronectin, required for cell adhesion. Sulfonate held on to albumin more strongly, producing a persistent hard corona likely to remain biocompatible. The mechanism is thought to be related to the higher energy of interaction between sulfonate and amine than between carboxylate and amine.
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Date Issued: 2019
Identifier: 2019_Summer_Surmaitis_fsu_0071E_15315
Format: Thesis

Title: Surface Characterization of Nanoparticles Using Nuclear Magnetic Resonance.
Creator: Zhang, Chengqi, Mattoussi, Hedi, Fadool, Debra Ann, Hu, Yan-yan, Kennemur, Justin Glenn, Florida State University, College of Arts and Sciences, Department of Chemistry and...
Show moreZhang, Chengqi, Mattoussi, Hedi, Fadool, Debra Ann, Hu, Yan-yan, Kennemur, Justin Glenn, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Nanocrystals such as semiconducting quantum dots and gold nanoparticles have attracted a lot of attentions due to their unique size- and shape- dependent optical properties. They have been used in various of biological applications such as sensing, imaging and drug delivery. In chapter 1, we provided a brief introduction about the optical properties of nanoparticles and why they are attractive. We also discuss several studies reported to prepare nanoparticle dispersions in aqueous media. In...
Show moreNanocrystals such as semiconducting quantum dots and gold nanoparticles have attracted a lot of attentions due to their unique size- and shape- dependent optical properties. They have been used in various of biological applications such as sensing, imaging and drug delivery. In chapter 1, we provided a brief introduction about the optical properties of nanoparticles and why they are attractive. We also discuss several studies reported to prepare nanoparticle dispersions in aqueous media. In Chapter 2, we presented a routine about how we studied the stoichiometry of the organic ligand shell on hydrophobic CdSe-ZnS QDs. Combining a few advanced solution phase NMR spectroscopy techniques, we were able to monitor the purification process and study the affinity of surface ligands. Other measurements were used to complement the results obtained from NMR spectroscopy, namely matrix assisted laser desorption ionization (MALDI) and FTIR. In Chapter 3, we extended this work to hydrophilic CdSe-ZnS core-shell quantum dots and Au nanoparticles where is more widely used in biological application. We chose three lipoic acid based polyethylene glycol (PEG)-modified ligands with different number of PEG chains or different number of anchoring group to study the effect of surface ligand architecture to the surface coverage. Free ligands in the buffer media and bound ligands on the nanoparticle surface were distinguished using diffusion ordered spectroscopy. Quantitative study was conducted to determine the ligand density. Factors that affect the surface coverage were discussed. In Chapter 4, we explored another important feature of nanoparticles - hydrodynamic size, a characteristic dimension that reflects the Brownian motion of objects, such as proteins, macromolecules and nanoparticles when dispersed (or homogeneously suspended) in any fluid phase. Both Dynamic light scattering (DLS) and ordered spectroscopy (DOSY) were used to extract the size information. The results were compared size by size. The similarity and differences of two techniques were discussed in details. In Chapter 5, we summarized the idea and contributions assembled in this dissertation followed by a discussion of the future outlook.
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Date Issued: 2019
Identifier: 2019_Summer_Zhang_fsu_0071E_15402
Format: Thesis

Title: Origin of Intrinsic Selectivity in F-Block Complexes.
Creator: Dan, David, Albrecht-Schmitt, Thomas E., Fajer, Piotr G., Hu, Yan-yan, Stiegman, Albert E., Dalal, Naresh S., Florida State University, College of Arts and Sciences, Department...
Show moreDan, David, Albrecht-Schmitt, Thomas E., Fajer, Piotr G., Hu, Yan-yan, Stiegman, Albert E., Dalal, Naresh S., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: This dissertation seeks to determine fundamental differences between lanthanides and actinides, as well as how their bonding influences ligand selectivity, for possible actinide separations from nuclear waste. The f-elements are significantly understudied when compared to other parts of the periodic table such as the d-block. Research into the f-elements, and more specifically the 5f elements, has undergone a renaissance of sorts with steadily increasing interest over the past few decades. It...
Show moreThis dissertation seeks to determine fundamental differences between lanthanides and actinides, as well as how their bonding influences ligand selectivity, for possible actinide separations from nuclear waste. The f-elements are significantly understudied when compared to other parts of the periodic table such as the d-block. Research into the f-elements, and more specifically the 5f elements, has undergone a renaissance of sorts with steadily increasing interest over the past few decades. It was previously predicted that the chemistry for later actinides was identical to that of their lanthanide counterparts. However, a review by Neidig et al., "The covalency in f-element complexes", helped introduce the concept of a greater degree of covalency in the actinides than in the lanthanides, creating a substantial dividing point for chemists to explore.1 The goal of this work is to shed further light on how later actinides behave and can be utilized. These new findings could help in the design of future separations techniques and materials. The first half of my dissertation will focus on the bonding in later actinides. I focus on an americium and californium complex [M(EtBTP)3][BPh4]3•3CH3CN (M = Am, Cf) (EtBTP = ethyl bistriazinyl pyridine). I also compare the [Am(EtBTP)3]3+ to its neodymium analog. Structural analysis of these complexes revealed that these compounds contain M3+ cations bound by tridentate EtBTP ligands, to create a tricapped trigonal prismatic geometry around the metal centers. Collection of high-resolution, single crystal X-ray diffraction data also allowed for reduction in bond distance estimated standard deviation (esd's) such that a slight contraction of Δ = 0.0158(18) Å in the Am‒N versus Nd‒N bond distances is observed, even though these cations ostensibly have matching ionic radii. Theoretical evaluation revealed enhanced metal-ligand bonding through back donation in the [Am(EtBTP)3]3+ complex that is absent in [Nd(EtBTP)3]3+. The [Cf(EtBTP)3]3+ complex was also compared to its lanthanide analogs, gadolinium and erbium. Upon analysis of these complexes, Cf showed significantly stronger bonding than Gd and Er. The contractions of some of the Cf bonds with the nitrogen atoms on EtBTP, revealed that Er could be a better analog for Cf complexes that are expected to have greater covalent characteristics. These two studies provide new information about how Cf and Am bond to ligands, and reveal how they differ from their lanthanide analogs. The second half of this dissertation centers on possible applications for f-block ligands. The two main points of interest are photochromic properties of [M(EtBTP)3][BPh4]3•3CH3CN (M = La, Eu, Gd, Yb) complexes, as well as a dithioamide ligand with possible separations applications. The [M(EtBTP)3][BPh4]3•3CH3CN (M = La, Eu, Gd, Yb) complexes exhibit a long-lived color change when exposed to intense light. This color change lasts on the order of hours, and increases in length as you go across the series. This color change is caused by a radical formation upon exposure to light. The long-lived nature of this color change is attributed to a trapped triplet excited state, with a relaxation that is moderated by the metal center. This shows the versatility of EtBTP and how it can be used in possible photochromic materials. The practicality of dithioamides as ligands for separations has yet to be greatly understood. The dithioamides were compared to their diamide counterparts, and the dithioamides showed greater selectivity for AmIII over EuIII. This selectivity is due to the softer donor properties of the sulfur atoms. This study showed the merit of studying other sulfur donor ligand systems for use in actinide extractions.
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Date Issued: 2019
Identifier: 2019_Summer_Dan_fsu_0071E_15333
Format: Thesis

Title: Structural and Dynamic Characterization of CrgA; a Small Helical Membrane Protein in a Lipid Bilayer Using Solid-State NMR.
Creator: Shin, Yiseul, Cross, Timothy A., Alamo, Rufina G., Hu, Yan-yan, Stagg, Scott, Fajer, Piotr G., Florida State University, College of Arts and Sciences, Department of Chemistry...
Show moreShin, Yiseul, Cross, Timothy A., Alamo, Rufina G., Hu, Yan-yan, Stagg, Scott, Fajer, Piotr G., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: CrgA is a small helical membrane protein from Mycobacterium tuberculosis (Mtb) and known to recruit other cell division proteins to the divisome, a substantial protein complex for Mtb cell division. There is a lack of information about the formation of the divisome, because most of the Mtb cell division proteins, including CrgA, do not have homologs in the traditional model bacteria, such as E. coli. Thus, structural information is needed to understand how these proteins interact and function...
Show moreCrgA is a small helical membrane protein from Mycobacterium tuberculosis (Mtb) and known to recruit other cell division proteins to the divisome, a substantial protein complex for Mtb cell division. There is a lack of information about the formation of the divisome, because most of the Mtb cell division proteins, including CrgA, do not have homologs in the traditional model bacteria, such as E. coli. Thus, structural information is needed to understand how these proteins interact and function in the divisome. However, small helical membrane proteins are such a challenging target for structural biology, because they are surrounded by the complex membrane environment, which has varying biophysical properties in terms of the dielectric constants, water concentration, fluidity, and a lateral pressure profile. The entire membrane protein does not experience the same environment, and therefore it is critical to understand the dynamics of each domain in order to characterize its structure. CrgA was characterized as having a cytoplasmic N-terminus (30 residues long) consisting of two dynamically different regions: an intrinsically disordered region (IDR) and a β-strand. Even though most Mtb divisome proteins were predicted to have at least one IDR, the roles of IDRs in membrane proteins has not been fully explored. In this dissertation, different solid-state NMR techniques were used to characterize the water soluble regions such as IDRs of membrane proteins. Identifying a small portion of the protein in the lipid interfacial region is not feasible without providing a native-like lipid bilayer environment. The observation of the β-strand addressed the importance of the appropriate membrane mimetic to characterize the interfacial region of CrgA. Also, unambiguous interhelical distance restraints are essential for determining the correct tertiary and quaternary structure of a helical membrane protein. However, high contents of hydrophobic residues in the transmembrane domain make sequence specific assignments a difficult task, so various methods, such as specific isotope labeling schemes and mutagenesis were implemented to obtain the distance restraints. The sequence specific assignment strategies presented here for CrgA can be applied to other membrane protein systems. Combining the structural restraints from both magic angle spinning and oriented sample NMR led to the dimeric structure of CrgA using molecular dynamics simulations. Additionally, the mutagenesis data helped to define the dimeric interface for CrgA. In the case of CrgA, it is necessary to sort out any residues at the helix-helix interfacial region in the same monomer versus those located in the monomer-monomer interface of the dimer. Excluding those residues involved in the dimer interface will facilitate defining the lipid-facing residues available for CrgA's binding partners. Since CrgA is a pivotal component of the divisome, the structure of CrgA will provide great insight into the formation of the divisome to advance knowledge about Mtb cell division.
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Date Issued: 2019
Identifier: 2019_Summer_Shin_fsu_0071E_15392
Format: Thesis

Title: Understanding Protien Corona Formation on Inorganic Nanocrystals.
Creator: Perng, Woody, Mattoussi, Hedi, Tang, Hengli, Steinbock, Oliver, Strouse, Geoffrey F., Florida State University, College of Arts and Sciences, Department of Chemistry and...
Show morePerng, Woody, Mattoussi, Hedi, Tang, Hengli, Steinbock, Oliver, Strouse, Geoffrey F., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Nonspecific interactions in biological media can lead to the formation of protein corona around nancolloids, which tend to alter their behavior and limit their utility when used as probes for imaging or sensing applications. Yet, understanding the corona buildup has been challenging. This dissertation focuses on understanding factors that govern corona formation and developing means to prevent such nonspecific adsorptions, using semiconductor and metallic nanocrystals as model nanocolloid...
Show moreNonspecific interactions in biological media can lead to the formation of protein corona around nancolloids, which tend to alter their behavior and limit their utility when used as probes for imaging or sensing applications. Yet, understanding the corona buildup has been challenging. This dissertation focuses on understanding factors that govern corona formation and developing means to prevent such nonspecific adsorptions, using semiconductor and metallic nanocrystals as model nanocolloid systems. In Chapter 1 we showcase the intrinsic photophysical properties of quantum dots (QDs) and gold nanocrystals (AuNCs), along with the growth mechanisms and synthetic routes. In addition, we introduce the definition of "protein corona", hard vs soft, factors that affect the corona composition, and its impact on biology and environment. We also provide an overview of the analytical techniques used and promising strategies applied in investigating and preventing nonspecific protein adsorptions, respectively. In Chapter 2 we investigate the role of surface coating on the promotion or prevention of protein corona around QDs, where we carefully vary the nature of the hydrophilic block in the surface coating, while maintaining the same dihydrolipoic acid (DHLA) bidentate coordinating motif. We first use agarose gel electrophoresis to track changes in the mobility shift upon exposure of the QDs to protein-rich media. We find that QDs capped with DHLA (which presents a hydrophobic alkyl chain terminated with a carboxyl group) could promote corona formation, in a concentration-dependent manner. However, when a polyethylene glycol block or a zwitterion group is appended onto DHLA, it yields a coating that prevents corona build-up. Additional gel experiments using SDS-PAGE allowed further characterization of the corona protein when formed. We find that for coating strategy based on the bidentate motif, only soft corona form around the DHLA-capped QDs. In chapter 3 we investigate the nonspecific protein adsorptions on AuNPs, where we strategically modify the ligand structures of a series of DHLA-based ligands. We use agarose gel electrophoresis to monitor any potential corona formation on AuNPs when exposed to bovine serum albumin (BSA) or fetal bovine serum (FBS). We find that AuNPs capped with dihydrolipoic acid (DHLA, a small alkyl-COOH) are prone to interactions with proteins, while capping AuNPs with polyethylene glycol- or zwitterion-appended DHLA significantly reduces corona buildup. Supplementing measurements using UV-Vis spectroscopy and dynamic light scattering have allowed further characterization of the role and the binding kinetics of these protein adsorptions. Our results clearly show that surface chemistry of the NP and the nature of the core material plays a significant role in corona formation. In chapter 4 we describe the effect of shape of gold nanocrystals on corona formation using nanospheres, nanostars, and nanorods. Such nanocrystals functionalized with poly(ethylene glycol), poly(isobutylene-alt-maleic anhydride) (PIMA), and PEG-appended PIMA induce or discourage nonspecific protein adsorptions depending on the surface coating used and the nature of the shape. We show that the presence of PEG moieties significantly inhibits the corona formation when exposed to complex fluids, independent to the shape of nanocrystals. We find that in absence of PEG, the shape of nanocrystals strongly intervenes with interactions at the nano-bio interface. Additionally, we show that the effect of shape on corona buildup prevails under different temperatures, a result that contributes highly to designing corona-free nanocrystals. In chapter 5 we include a summary of the findings and implications described in this dissertation, along with a discussion of the future outlook in the corona science.
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Date Issued: 2019
Identifier: 2019_Summer_Perng_fsu_0071E_15398
Format: Thesis

Title: Chemical Garden Catalysis of Prebiotic Chemistry.
Creator: Omran, Arthur P. (Arthur Phillip), Steinbock, Oliver, Blaber, Michael, DePrince, A. Eugene, Yang, Wei, Florida State University, College of Arts and Sciences, Department of...
Show moreOmran, Arthur P. (Arthur Phillip), Steinbock, Oliver, Blaber, Michael, DePrince, A. Eugene, Yang, Wei, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Prebiotic processes required a reliable source of free energy and complex chemical mixtures that likely included sugars. The formose reaction is a potential source of those sugars but is tied to alkaline conditions and elevated temperatures, under which these sugars rapidly decay. Here we show that calcium, barium and iron based chemical gardens catalyze the formose reaction to produce glucose, ribose, and other carbohydrates. These thin inorganic membranes are analogs of hydrothermal vent...
Show morePrebiotic processes required a reliable source of free energy and complex chemical mixtures that likely included sugars. The formose reaction is a potential source of those sugars but is tied to alkaline conditions and elevated temperatures, under which these sugars rapidly decay. Here we show that calcium, barium and iron based chemical gardens catalyze the formose reaction to produce glucose, ribose, and other carbohydrates. These thin inorganic membranes are analogs of hydrothermal vent materials—a possible place for the origin of life—and similarly exposed to very steep pH gradients. Supported by simulations of a simple reaction-diffusion model, we show that such gradients allow for the dynamic accumulation of sugars in specific layers of the thin membrane. This spatial separation of sugar production and accumulation might have been one of the earliest examples of pre-biological compartmentalization.
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Date Issued: 2019
Identifier: 2019_Summer_Omran_fsu_0071E_15278
Format: Thesis

Title: Mechanistic Enzymological Studies of Human Glucokinase and the Development of a Biocatalyst for Chemical Synthesis.
Creator: Sternisha, Shawn M., Miller, Brian G., Zhu, Fanxiu, Hoekman, Timothy, Yang, Wei, Frederich, James H., Florida State University, College of Arts and Sciences, Department of...
Show moreSternisha, Shawn M., Miller, Brian G., Zhu, Fanxiu, Hoekman, Timothy, Yang, Wei, Frederich, James H., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: The hexokinase (HK) family of enzymes catalyze the conversion of glucose to glucose 6-phosphate in a process that is utilized for energy production in most organisms. Hexokinase IV, commonly known as glucokinase (GCK), is functionally distinct from the rest of the HK isozymes. It is characterized by a high substrate concentration at half-maximal velocity and is not inhibited by an abundance of its product. GCK also displays positive kinetic cooperativity, despite functioning as a monomer and...
Show moreThe hexokinase (HK) family of enzymes catalyze the conversion of glucose to glucose 6-phosphate in a process that is utilized for energy production in most organisms. Hexokinase IV, commonly known as glucokinase (GCK), is functionally distinct from the rest of the HK isozymes. It is characterized by a high substrate concentration at half-maximal velocity and is not inhibited by an abundance of its product. GCK also displays positive kinetic cooperativity, despite functioning as a monomer and containing only one glucose binding site. This responsiveness is such that the inflection point occurs in the range of physiological blood glucose levels, providing the enzyme with exceptional sensitivity in this region. GCK's unique functional properties allow it to control the rates of insulin release and glycogen synthesis. The significance of proper GCK function is emphasized by various pathological conditions that arise from mutations in the gck gene. These discoveries are expanded upon in Chapter 1 and have led to GCK being considered the glucose sensor of the body. Millisecond timescale fluctuations of the small domain have been shown to be essential for cooperativity in GCK. However, a detailed picture of GCK's dynamic conformational landscape, including the number of accessible states, their relative populations, and the timescales on which they interconvert is absent in the literature. In Chapter 2, we map the intrinsic dynamics and structural heterogeneity of GCK on the nanosecond timescale using a combination of unnatural amino acid incorporation, time-resolved fluorescence spectroscopy and 19F nuclear magnetic resonance spectroscopy. Based on these results, we propose a catalytic model in which cooperativity originates from correlation between nanosecond and millisecond timescale motions. Activating GCK mutations abolish cooperativity and manifest themselves in the clinic as congenital hyperinsulinism. In Chapter 3, we use steady- and transient-state kinetics, and hydrogen-deuterium exchange mass spectrometry, to demonstrate that mutational activation of GCK occurs via two distinct mechanisms: α and β. Our data reveal that α-activation results from a shift in the conformational ensemble of unliganded GCK toward a state resembling the glucose-bound, closed conformation. β-type activation is instead caused by increased mobile loop dynamics, which accelerate the product release rate. This work elucidates the molecular basis of naturally occurring, activated GCK disease variants. Due to its essential role in maintaining whole-body glucose homeostasis, GCK activity is extensively regulated at virtually every level in the cell. The hormonal, metabolic, and transcriptional regulation of GCK have been described in great detail by other laboratories.1,2 Protein-protein interactions and post-translational modifications involving GCK elicit an array of physiological consequences and intrinsic conformational dynamics provide GCK with an additional layer of functional control. In Chapter 4, we offer insights into how these regulatory strategies are integrated and coordinated within the broader context of the cell. Of these regulatory mechanisms, the post-translational conjugation of the small ubiquitin-like modifier (SUMO1) protein to GCK remains one of the most poorly understood. Recently, it was reported that SUMOylation increases GCK's activity and stability, and mediates nuclear translocation of the enzyme.3,4 However, the inability to isolate homogenous, SUMOylated proteins often inhibits full characterization of the modification. In Chapter 5 we describe our efforts to generate SUMOylated GCK using semi-synthetic and coexpression approaches. We conclude with a look to the future, emphasizing the need for continued investigation and describing future experiments. In Chapter 6, we deviate from investigations of GCK and describe our efforts to characterize CyrI, a unique iron-dependent, nonheme oxygenase. This enzyme is expressed in cyanobacteria, where it catalyzes the final step in the biosynthesis of the toxic drinking water contaminant cylindrospermopsin. CyrI catalyzes a challenging C-H oxidation step with exquisite selectivity and appears to be depend on a sulfate group as a substrate recognition motif. CyrI is intriguing to develop from a chemical synthesis perspective as the selective functionalization of C-H bonds among numerous similarly reactive C-H bonds is a considerable challenge in organic synthesis. We detail our analysis of CyrI stability and crystallization and provide insights into future experimentation.
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Date Issued: 2019
Identifier: 2019_Summer_Sternisha_fsu_0071E_15294
Format: Thesis

Title: Actinide Fluorides.
Creator: Chemey, Alexander Theodore, Albrecht-Schmitt, Thomas E., Tabor, Samuel L., Latturner, Susan, Hanson, Kenneth G., Florida State University, College of Arts and Sciences,...
Show moreChemey, Alexander Theodore, Albrecht-Schmitt, Thomas E., Tabor, Samuel L., Latturner, Susan, Hanson, Kenneth G., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: The periodic table of the elements, derived from numerous attempts in the 1800s to systematically examine the chemistry found in nature, has seen a stark evolution over the last century. The elements of the actinide series are the frontier of a radical discontinuity in periodicity, driven by a relativistic reorganization of the frontier orbitals. Characterization of the chemistry of these elements with simple model species enables detailed coordination between structural chemistry and...
Show moreThe periodic table of the elements, derived from numerous attempts in the 1800s to systematically examine the chemistry found in nature, has seen a stark evolution over the last century. The elements of the actinide series are the frontier of a radical discontinuity in periodicity, driven by a relativistic reorganization of the frontier orbitals. Characterization of the chemistry of these elements with simple model species enables detailed coordination between structural chemistry and theoretical characterization. Such examinations advance understanding of these relativistic shifts. With the ever-growing influence of these effects, periodic trends on the table the elements break down, and synthetic elements beyond uranium offer new opportunities to probe these divergent and nonlinear chemistries. The introductory chapter addresses the history of the synthesis and the initial chemical characterization of the transuranium elements, with a brief basic introduction given to discuss the reaction physics which will follow. These elements share a single common feature in that they all have large Z values, and thus have electronic structures that are significantly altered by both scalar relativistic effects and spin-orbit coupling. These effects scale nonlinearly with increasing Z and create unexpected deviations both across series and down groups of elements. The magnitude of these effects is large enough that orbital energies rearrange and mix in ways that complicate incomplete depictions that are based solely on electron repulsion. The second chapter discusses calculations with nuclear reaction codes to examine a potential production rate improvement that may be derived by super-heavy synthesis with reactions run in inverse kinematics. This result is particularly important for continuing the evolution of the periodic table, as increased production rates enable new spectroscopic analyses of electronic and nuclear structure that can, in future years, potentially rewrite our understanding of relativity at the most extreme scale heretofore produced. The third chapter discusses new structural, spectroscopic, and theoretical features of uranium fluorides that are relevant for fundamental uranium(IV) chemistry and actinide fluoride reactors. The simple system of tetraammonium octafluorouranate is employed to derive fundamental understanding of the uranium-fluorine interaction. The structure is composed of isolated molecules, enabling a clear look at the U4+ (f 2) species in the most ionic bonding environment possible, without the possibility of direct interactions or strong interactions through ligands between uranium centers. Characterization of single-crystals by x-ray diffraction, absorption spectroscopy, and magnetic analysis up to 45 T is interwoven with extensive theoretical treatment by CASSCF. The influence of different active spaces and representations of the structure is examined in the context of the experimental evidence. The Interacting Quantum Atoms method is used to examine the nature of the U-F bond, concluding that there is a non-negligible degree of covalent character (9% of the total bond energy) even with the most ionic simple anion of fluoride. Two new sodium uranium(IV) pentafluorides were synthesized from uranium dioxide, HF, and NaF under mild hydrothermal conditions. Although β-NaUF5·H2O crystallizes in the (lower) monoclinic crystal class, it possesses greater crystal lattice energy than the previously-known orthorhombic α-NaUF5·H2O. Trigonal β-NaUF5 possess significantly different bonding between [UF9]5- moieties than the α-phase, with higher symmetry and greater lattice energy than its orthorhombic structural isomer, which is most directly comparable in structure to Na3,4M2+/3+U6F30. Single-crystal absorption spectra of these compounds are reported and correlated. Simulated powder x-ray diffraction data are also reported and compared to address a (mis)identification of the NaUF5 series that dates back to the Manhattan Project. The final textual chapter extends the methods discussed in previous chapters to the actinide series, with new lithium plutonium fluorides analyzed and placed into the broader context of actinide fluorides, including a new evaluation of an analogous zirconium structure. The structure of Li4ZrF8 was refined from single crystal X-ray diffraction data. Alkali zirconium fluorides are important in nuclear-relevant technologies, and zirconium is commonly employed as an analogue for tetravalent f-block elements. This result is largely consistent with prior reports, but with significant improvements in precision. The similar reaction of 242PuO2 with HF and LiF under hydrothermal conditions results in the formation of Li4PuF8 and LiPuF5. These compounds were structurally characterized using single crystal X–ray diffraction and UV–vis–NIR absorption spectroscopy. The structure of Li4PuF8 consists of [PuF8]4‒ anions that adopt a non-bridged bicapped trigonal prismatic geometry with approximate C2v symmetry. In contrast, LiPuF5 forms a dense three–dimensional network constructed from [PuF9]5‒ units that are bridged by fluoride anions. The Pu4+ cations are found within tricapped trigonal prisms. Extensive theoretical analysis of electronic and bonding interactions is included with comparison between results derived from CASSCF at different levels of theory, QTAIM, IQA, NLMO, and WBO analyses. Covalent interactions in these compounds are examined and intra–molecular trends in covalent and electrostatic interactions are discussed.
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Date Issued: 2019
Identifier: 2019_Fall_Chemey_fsu_0071E_15478
Format: Thesis

Title: Chiral Micellar Electrokinetic Chromatography Analysis of Cellular Secretions.
Creator: Evans, Kimberly Celeste, Roper, Michael Gabriel, Trombley, Paul Q., Hu, Yan-yan, Strouse, Geoffrey F., Florida State University, College of Arts and Sciences, Department of...
Show moreEvans, Kimberly Celeste, Roper, Michael Gabriel, Trombley, Paul Q., Hu, Yan-yan, Strouse, Geoffrey F., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: The work in this dissertation presents a chiral separation method for the quantitative measurement of primary amines secreted from murine islets of Langerhans along with whole brain tissue and astrocytes. Primary amines, including amino acids, can have a chiral center which leads to nomenclature of the resulting enantiomers, L- or D-. Most alpha amino acids exist in either form, however, prior to the 1980’s D-amino acids (DAAs) were thought to not be utilized by cells.1 Of the alpha amino...
Show moreThe work in this dissertation presents a chiral separation method for the quantitative measurement of primary amines secreted from murine islets of Langerhans along with whole brain tissue and astrocytes. Primary amines, including amino acids, can have a chiral center which leads to nomenclature of the resulting enantiomers, L- or D-. Most alpha amino acids exist in either form, however, prior to the 1980’s D-amino acids (DAAs) were thought to not be utilized by cells.1 Of the alpha amino acids, D-serine (D-Ser)2, D-alanine (D-Ala)3,4, and D-aspartate (D-Asp)5,6, to name a few, have been identified throughout the body in considerably lower concentrations to the corresponding enantiomer. Even at low concentrations, DAAs are important to the overall homeostasis of the mammalian body. For example, D-Ser can activate the Gly binding site on N-methyl-D-aspartate receptors (NMDARs). D-Ser appears throughout the brain in varying concentrations depending on the region.7,8 Unfortunately, detection of the D-enantiomers is difficult when the sheer abundance of the L-enantiomer is considered. Several methods have monitored primary amines from numerous biological systems, including murine islets of Langerhans, whether directly or indirectly.9-14 In recent years, direct methods for monitoring cellular content have gained some ground in effort to have quantitative methods to measure chiral amines. Direct measurements of chiral amines would elucidate the roles of DAAs better compared to the indirect methods that require assumptions about pathways or signaling mechanisms. In this work, the optimized separation conditions utilized four internal standards to quantify 17 primary amines, of which were 5 D-amino acids, with limits of detection (LOD) ranging from 0.3 nM to 8 nM. The normalized migration times had relative standard deviations (RSD) less than 0.6% and the majority of the normalized peak areas were less than 10% RSD. The effects of glucose were tested on small batches of islets and a small shoulder corresponding to the same migration time as D-Ser standard was observed under high glucose. While the islet samples did not yield any D-amino acid peak, other tissues are known to contain numerous D-amino acids such as whole brain tissue. Utilizing the optimized chiral separation method, changes in D-Ser secretion and content from three different brain regions under two conditions were investigated. D-Ser is proposed to be in lower concentrations, secreted or content, in murine brains after identified with the status condition compared to the non-status brains. Samples were treated in the same manner as the islet samples with one caveat, β-Ala was no longer considered an internal standard due to its presence in the samples. The chiral separation method was capable of observing D-Ser in most of the samples, which was identified through the use of D-Ser standard spikes and D-amino acid oxidase (DAAO) to eliminate of the peak in question. The role of pure populations of astrocytes has yet to be fully examined in relation to the effects of drug abuse, specifically the direct effect of D-Ser concentration in cellular content. Due to differences in astrocytic populations based on brain region, a different set of three brain regions were selected for the next experiment. Content from whole brain regions from the hippocampus, cortex, and olfactory bulb were examined utilizing the optimized chiral separation method for the presence of D-Ser. To elucidate if astrocytes contained D-Ser in the absence of neurons, cultures of only astrocytes and co-cultures of astrocytes with neurons from the previously mentioned regions were stimulated with high potassium to induce release of cellular content.
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Date Issued: 2019
Identifier: 2019_Fall_Evans_fsu_0071E_15475
Format: Thesis

Title: Understanding the Behavior and Structure of Nanocrystalline Material through the Interactions of Photons.
Creator: Hardy, David A. (David Allen), Strouse, Geoffrey F., Oates, William, Stiegman, Albert E., Hanson, Kenneth G., Florida State University, College of Arts and Sciences, Department...
Show moreHardy, David A. (David Allen), Strouse, Geoffrey F., Oates, William, Stiegman, Albert E., Hanson, Kenneth G., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Ligand passivated nanoparticles have applications in solid-state lighting, plasmonics, and catalysis. At the nanoscale, the properties of these materials can be manipulated by reaction kinetics, allowing for systematic control to achieve desired functionalities and performance efficiency. Analysis of these properties and evaluating their fundamental behavior is challenging due to the complex chemistry at the nanoscale. Therefore, a combination of analytical techniques such as TEM, SEM, pXRD,...
Show moreLigand passivated nanoparticles have applications in solid-state lighting, plasmonics, and catalysis. At the nanoscale, the properties of these materials can be manipulated by reaction kinetics, allowing for systematic control to achieve desired functionalities and performance efficiency. Analysis of these properties and evaluating their fundamental behavior is challenging due to the complex chemistry at the nanoscale. Therefore, a combination of analytical techniques such as TEM, SEM, pXRD, NMR, and optical methods are required to study the structure and properties of these materials. This dissertation will consist of two topics covering nanoparticle synthesis and their applications. The first topic will discuss the use of 2 nm lanthanide doped nanospinels (Ln:ZnAl2O4, Ln = Tb, Eu) as down-shifting phosphors for solid-state lighting. Emission quantum yields up to 50% are achieved following energy transfer from a surface coordinating ligand. The second topic will discuss the synthesis and isolation of catalytic material from an iron-cobalt Prussian blue analogue (PBA). The isolated catalytic material retain elemental compositions and obey a scaling law with respect to the seed PBA, suggesting a templated interconversion.
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Date Issued: 2019
Identifier: 2019_Fall_Hardy_fsu_0071E_15492
Format: Thesis

$High Refractive Index Hybrid Polymer Composites$

Title: High Refractive Index Hybrid Polymer Composites.
Creator: Bello Da Silva Filho, Edmundo, Stiegman, Albert E., Alamo, Rufina G., Roper, Michael Gabriel, Frederich, James H., Florida State University, College of Arts and Sciences,...
Show moreBello Da Silva Filho, Edmundo, Stiegman, Albert E., Alamo, Rufina G., Roper, Michael Gabriel, Frederich, James H., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Transparent hybrid polymers created through thiol-ene click chemistry were obtained. Methacrylate and acrylate capped zirconium oxo-clusters (ZOCs) were incorporated into two thiol-ene polymer networks. The vinyl capping groups potentially enable the ZOCs to become an integral part of the thiol-ene network. The ZOCs are reasonably soluble in the thiol and ene monomers yielding a loading of 1 wt. -%. The resulting polymer composites were highly transparent in the visible region and exhibited...
Show moreTransparent hybrid polymers created through thiol-ene click chemistry were obtained. Methacrylate and acrylate capped zirconium oxo-clusters (ZOCs) were incorporated into two thiol-ene polymer networks. The vinyl capping groups potentially enable the ZOCs to become an integral part of the thiol-ene network. The ZOCs are reasonably soluble in the thiol and ene monomers yielding a loading of 1 wt. -%. The resulting polymer composites were highly transparent in the visible region and exhibited significant enhancement in the refractive indices with measured values. Moreover, dynamic mechanical analysis (DMA) revealed that all the composites exhibited good mechanical strength and were robust enough to undergo machining and/or polishing without fracture. In a subsequent study, a series of hard transparent thermoset polymers samples made of tetravinylsilane (TVS) and 1.3-benzenedithiol (BDT) with varying loadings of a zirconium oxo-cluster Zr6(OH)4O4(OMc)12 (ZOC) was synthesized. The resulting polymers exhibited an increase in the refractive index (n) when compared to the parent polymer made from TVS and BDT, which refractive index is n = 1.699. The increase in refractive index reached a maximum value of 1.711 at a loading of 3 wt.% and then began to decrease as the concentration of ZOC increases in the polymer matrix. The refractive index of ZOC itself was determined to be between 1.539 and 1.542 when measured by the Becke line test. Notably these values are lower than the TVS-BDT polymer matrix into which it is incorporated. As such, the observation that the addition of small amounts of ZOC can increase the refractive index when incorporated into the TVS-BDT polymer is unexpected. It was found that this behavior was the result of changes in the density of the resultant polymer. Changes in glass transition temperature (Tg) and refractive index of the composites were shown to correlate with the trend in the degree of cross-linking, as monitored by Raman spectroscopy, which occurred to be increased at low loadings then began to decrease as the ZOC concentration got larger. The origin of the observed trend in cross-linking is not fully apparent, however solid state 29Si NMR show evidence for specific interactions between the silicon in the polymer matrix and the ZOC. It is suggested that these interactions happen through coordination of thioether and thiol groups to empty d orbitals in the zirconium which reduces its ability to cross link. Motivated by the discoveries on the aforementioned work, two series of poly (methyl methacrylate) containing increasing loadings of 1,3,5-trithiane-based additives were produced. The refractive index of samples containing the additives were higher than the parent polymer, and the respective densities tended to be slightly lower if, again, compared to the parent polymer. The results seem to indicate that the tested additives contribute to an increase in refractive index of the polymers but its presence in the material compromises its molecular packing, that generates less dense composites.
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Date Issued: 2019
Identifier: 2019_Fall_BelloDaSilvaFilho_fsu_0071E_15621
Format: Thesis

Title: Cancer Immune Evasion Mechanisms and the Role of Granzyme B in Tumor Progression.
Creator: Burjas Bou-Dargham, Mayassa J., Sang, Qing-Xiang, Zhang, Jinfeng, Zhu, Fanxiu, Logan, Timothy M., Bleiholder, Christian, Florida State University, College of Arts and Sciences,...
Show moreBurjas Bou-Dargham, Mayassa J., Sang, Qing-Xiang, Zhang, Jinfeng, Zhu, Fanxiu, Logan, Timothy M., Bleiholder, Christian, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Major hallmarks of cancer include metastasis and evading the immune system. Despite cutting edge treatments developed in an era of extensive cancer research, immunotherapy has not been proven efficient enough in solid tumors, and metastasis still accounts for the majority of cancer deaths. The overall unsatisfactory response rates to immunotherapy are mainly due to the lack of biomarkers that can predict a patient’s response and the lack of a good understanding of the different immune cell...
Show moreMajor hallmarks of cancer include metastasis and evading the immune system. Despite cutting edge treatments developed in an era of extensive cancer research, immunotherapy has not been proven efficient enough in solid tumors, and metastasis still accounts for the majority of cancer deaths. The overall unsatisfactory response rates to immunotherapy are mainly due to the lack of biomarkers that can predict a patient’s response and the lack of a good understanding of the different immune cell infiltration trends observed in tumors. To address these gaps in breast and prostate cancer, RNA sequenced data for breast and prostate cancer samples were obtained from The Cancer Genome Atlas (TCGA) and analyzed to identify immune evasion mechanisms and understand immune cell infiltration. Breast and prostate cancer populations were each clustered into different immune evasion groups. Then biomarkers predictive of the identified clusters were identified and could be used as predictors of immune evasion and the corresponding immunotherapy options. In breast cancer, 77.4% of the clustered tumor specimens showed evasion through transforming growth factor-beta (TGF-β), 57.8% through decoy receptor 3 (DcR3), 48.0% through cytotoxic T-lymphocyte-associated protein 4 (CTLA4), and 34.3% through programmed cell death-1 (PD-1). Prostate cancer clustering showed immunologic ignorance in 89.77% of samples, upregulated CTLA4 in 58.8%, and upregulated DcR3 expression in 51.6%. However, in most clusters, there were different combinations of evasion mechanisms, which could explain the failure of immune monotherapy approaches. The immune profiling of breast cancer samples suggests that immunologically cold tumors are not only less immunogenic than hot tumors, but also have a high abundance of the pro-tumorigenic M2 macrophages and a stiff matrix, all of which can impede immune cell infiltration. Thus, M2 is a novel prognostic factor in breast cancer and a promising drug target. Epithelial-mesenchymal transition (EMT) is a critical early step in cancer metastasis. Further understanding of this process may shed light on how to stop the spreading of cancer cells. Androgen-repressed prostate cancer (ARCaP) cell lines representative of the epithelial (ARCaP-E) and mesenchymal (ARCaP-M) phenotypes were used and their secretome was investigated using proteomics approaches. High levels of proteins involved in bone remodeling and extracellular matrix degradation were detected in the ARCaP-M cells, indicative of a bone metastatic phenotype. LC-MS/MS analysis showed that the serine protease granzyme B (GZMB) was 800-fold higher in ARCaP-M conditioned media. Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) and Western blot further showed that GZMB was expressed and translated in ARCaP-M cells and the protein is only detected extracellularly. ARCaP-M cells with the GZMB gene knockdown using RNA interference showed a markedly reduced invasiveness as demonstrated by the Matrigel invasion assay. Our findings indicate a novel role for GZMB in prostate cancer invasion and extracellular matrix degradation.
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Date Issued: 2019
Identifier: 2019_Fall_BurjasBouDargham_fsu_0071E_15520
Format: Thesis

Title: Low Dimensional Electron Correlated Materials.
Creator: Pak, Chongin, Shatruk, Mykhailo, Hellstrom, Eric, Albrecht-Schmitt, Thomas E., Stiegman, Albert E., Florida State University, College of Arts and Sciences, Department of...
Show morePak, Chongin, Shatruk, Mykhailo, Hellstrom, Eric, Albrecht-Schmitt, Thomas E., Stiegman, Albert E., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: This PhD thesis is devoted to investigation of inorganic materials with low-dimensional structures. Such materials attract significant fundamental and applied interest due to the potential to achieve highly anisotropic properties, which can be controlled by various external stimuli. After brief introduction to this research area in Chapter 1 and description of experimental and theoretical methods in Chapter 2, we describe the study of ternary manganese selenides, Na2Mn2Se3 and Na2Mn3Se4, in...
Show moreThis PhD thesis is devoted to investigation of inorganic materials with low-dimensional structures. Such materials attract significant fundamental and applied interest due to the potential to achieve highly anisotropic properties, which can be controlled by various external stimuli. After brief introduction to this research area in Chapter 1 and description of experimental and theoretical methods in Chapter 2, we describe the study of ternary manganese selenides, Na2Mn2Se3 and Na2Mn3Se4, in Chapter 3. The relationship between the layered crystal structure of these materials and their magnetic behavior is discussed based on the arrangement of magnetic sites in each layer, and results of quantum chemical calculation on Na2Mn2Se3 and Na2Mn3Se4 indicate both compounds are semiconductors. Na2Mn2Se3 does not exhibit magnetic ordering down to 1.8 K, but strong antiferromagnetic correlations were confirmed by field-dependent magnetization measurements. Neutron diffraction study on powder and single crystal samples also did not reveal clear signatures of magnetic ordering. The strong magnetic frustration was confirmed by calculating the frustration factor. A new antiferromagnetic compound, Na2Mn3Se4, was also discovered. It exhibits antiferromagnetic transition at 27 K. Additional magnetic transition is observed at 50 K in single crystal and powder neutron diffraction studies. The magnetic structure of this material shows a complex combination of ferromagnetic and antiferromagnetic interactions that alternate along the crystallographic a-axis. Strong magnetic frustration due to triangulated spin arrangement is confirmed. Synthesis, crystal structure, and magnetic properties of layered materials ACeSe2 (A = Li, Na) are described in Chapter 4. The unconventional magnetism of these compounds is due to the arrangement of magnetic sites on the regular triangular lattice, which causes strong magnetic frustration. A detailed investigation of magnetic properties reveals no magnetic ordering down to 1.8 K. The Weiss constant, determined from fitting experimental data to the Curie-Weiss law, is –71 K, suggesting a very large magnetic frustration factor for this system. The relationship between the structural and magnetic properties of the geometrically frustrated magnetic system is discussed. The extension of studies of layered structures to potentially two-dimensional magnetic materials, Fe3GeTe2 and Bi2MnSe4, is described in Chapter 5. These crystal structures contain stacks of 2D magnetic sheets interacting through weak interlayer van der Waals forces. Chemical vapor transport method is employed to grow high-quality single crystals. The structural and magnetic properties of these materials, including magnetocrystalline anisotropy of bulk samples, were confirmed by temperature dependent magnetic susceptibility measurement. The potential to modify magnetic behavior for few-layer materials, down to the monolayer limit obtained by mechanical or liquid phase exfoliation methods, is yet to be investigated. Chapter 6 describes the study of one-dimensional structures that contain tubular or ribbon-shaped polyphosphide fragments. Thin nano-ribbons were obtained by mechanical and liquid-phase exfoliation of bulk KP15, due to the weak van der Waals interactions between the polyphosphide tubes. Optical bandgap slightly increases as the thickness of nano-ribbons decreases which is an indication of bandgap tunability in the material. Nevertheless, the results of Raman spectroscopy, high resolution transmission electron microscopy, and selected area electron diffraction studies suggest the decreased stability of the samples that contain thinner nanoribbons (<20 nm).
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Date Issued: 2018
Identifier: 2018_Su_Pak_fsu_0071E_14679
Format: Thesis

Title: Crystal Structure Prediction via Deep Learning.
Creator: Ryan, Kevin, Shatruk, Mykhailo, Barbu, Adrian G., DePrince, A. Eugene, Latturner, Susan, Florida State University, College of Arts and Sciences, Department of Chemistry and...
Show moreRyan, Kevin, Shatruk, Mykhailo, Barbu, Adrian G., DePrince, A. Eugene, Latturner, Susan, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Vast information on existing crystal structures, which is available through the large open-access and commercialized repositories of crystallographic data, provides an excellent starting point for the implementation of deep learning techniques to the discovery of hidden relationships that might be contained in such large datasets. The machine learning algorithm can be thought of as a fitting procedure for a complicated heuristic model using a large amount of data.1-2 This model is later...
Show moreVast information on existing crystal structures, which is available through the large open-access and commercialized repositories of crystallographic data, provides an excellent starting point for the implementation of deep learning techniques to the discovery of hidden relationships that might be contained in such large datasets. The machine learning algorithm can be thought of as a fitting procedure for a complicated heuristic model using a large amount of data.1-2 This model is later tested to estimate its ability to generalize to unknown crystal structures in a holdout set, i.e. its predictive ability. Herein, we describe a neural network model trained to predict the likelihood of chemical elements adopting different topologies of atomic sites in known crystal structures. The neural network is shown examples of topologies from known crystal structures and trained to predict the element that adopted that topology. We apply the trained model to predict possible compositions of unknown compounds that might be pursued by a synthetic chemist. We demonstrate that the deep neural network is capable of automatically “discovering” relevant descriptors from high-dimensional “raw representations” of the crystallographic data. Since the input data contain purely geometrical and topological information, any chemical knowledge residing within the neural network output must have been learned during training, and thus was “discovered”. The neural network’s learned representation of local topology shows evidence of known geometric and chemical trends not explicitly provided to the network during training.
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Date Issued: 2018
Identifier: 2018_Su_Ryan_fsu_0071E_14685
Format: Thesis

Title: Electronically Coupled Photon Upconversion Solar Cells via Molecular Self-Assembled Bilayers.
Creator: Hill, Sean Patrick, Hanson, Kenneth G., Oates, William, Schlenoff, Joseph B., Shatruk, Mykhailo, Florida State University, College of Arts and Sciences, Department of Chemistry...
Show moreHill, Sean Patrick, Hanson, Kenneth G., Oates, William, Schlenoff, Joseph B., Shatruk, Mykhailo, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Photon upconversion (UC) is a unique process that has garnered increased interest in the past decade as a way to harness lower energy photons and convert them to higher energy for use in a host of applications. In molecular UC, a sensitizer molecule absorbs low energy light and undergoes intersystem crossing to generate a triplet excited state. Subsequent sensitizer-to-acceptor triplet energy transfer (TET) yields acceptor molecules in the triplet excited state. Two triplet acceptor molecules...
Show morePhoton upconversion (UC) is a unique process that has garnered increased interest in the past decade as a way to harness lower energy photons and convert them to higher energy for use in a host of applications. In molecular UC, a sensitizer molecule absorbs low energy light and undergoes intersystem crossing to generate a triplet excited state. Subsequent sensitizer-to-acceptor triplet energy transfer (TET) yields acceptor molecules in the triplet excited state. Two triplet acceptor molecules in proximity can then undergo triplet−triplet annihilation (TTA), generating one excited singlet acceptor and one ground state acceptor. Emission from the resulting singlet excited state is hypsochromically shifted relative to the excitation light and thus the photon energy is upconverted during the process. Application of molecular TTA-UC into solar cell devices, where the conversion of photons of energy below the bandgap of typical absorbing materials to those of higher energy could yield higher efficiencies, is theoretically predicted to circumvent the theoretical efficiency limit of a standard solar cell device from ~33% to more than ~43%. One approach is the use of self-assembled bilayers of sensitizer and acceptor molecules electronically coupled into a dye-sensitized solar cell (DSSC) type device to facilitate TTA-UC and direct charge separation at the organic-inorganic hybrid interface of the self-assembled bilayer and the mesoporous nanoparticle semiconductor substrate. This dissertation explores the assembly of these bilayer structures onto films of zirconium dioxide (ZrO2) and titanium dioxide (TiO2) mesoporous nanoparticle substrates in order to study the enablement of photon upconverted emission and photocurrent generation, respectively. Herein it is experimentally outlined how self-assembled bilayers can be formed via a simple, stepwise soaking procedure to afford films with surface bound acceptors followed by linking of sensitizers to acceptors via metal ion coordination. These films are shown to facilitate TTA-UC on ZrO2 as well as allow direct charge separation of the upconverted singlet state from acceptor molecules on TiO2, even under solar intensity. These self-assembled bilayer films are compared to alternative solution based systems to show they are not limited by some of the common loss pathways. Finally, the role of the redox mediator in TTA-UC solar cell devices is explored in order to understand the impact of adding an additional component relative to the TTA-UC system and how they affect excited state species. Commentary on problems faced in the system will be given along with insights into optimizing key processes to maximize efficiency.
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Date Issued: 2018
Identifier: 2018_Sp_Hill_fsu_0071E_14305
Format: Thesis

Title: The Development of New Strategies to Harness Radicals for the Preparation of N-Heterocycles.
Creator: Evoniuk, Christopher J. (Christopher Jordan), Alabugin, Igor V., Blaber, Michael, Hanson, Kenneth G., Kennemur, Justin Glenn, Florida State University, College of Arts and...
Show moreEvoniuk, Christopher J. (Christopher Jordan), Alabugin, Igor V., Blaber, Michael, Hanson, Kenneth G., Kennemur, Justin Glenn, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: This work focuses on the development of new synthetic methods for the preparation of various N-heterocycles. While I have encountered many road blocks throughout my PhD, it has taught me how to solve a wide variety of challenges through perseverance, critical thinking and collaboration. I have successfully developed multiple projects stemming from my independent ideas for new chemical transformations. The projects range from cyclizations of o-alkenylisocyanides using a variety of radical...
Show moreThis work focuses on the development of new synthetic methods for the preparation of various N-heterocycles. While I have encountered many road blocks throughout my PhD, it has taught me how to solve a wide variety of challenges through perseverance, critical thinking and collaboration. I have successfully developed multiple projects stemming from my independent ideas for new chemical transformations. The projects range from cyclizations of o-alkenylisocyanides using a variety of radical precursors to C(sp3)-H amination (with and without transition metals) reactions. The discovery of selective addition of radicals to isonitriles could be harnessed to initiate a radical cascade that was designed to overcome the stereoelectronic restrictions on homoallylic ring expansion in alkyne reactions by using alkenes as synthetic equivalents of alkynes. This allowed us to establish a new route for N-heteroaromatics by coupling a homoallylic ring expansion with a stereoelectronically assisted C-C bond scission to yield the formal “6-endo” products. Additionally we have developed multiple protocols for C(sp3)-H aminations. Firstly, a transition metal mediated approach using FeCl3/DDQ for an intramolecular C(sp3)-H oxidative amination. In this reaction, an aniline group can activate the molecule for single-electron-transfer while also acting as an internal nucleophile to trap reactive intermediates. Following a consecutive electron transfer oxidation process, we can couple free amines with -CH2- groups to afford aromatic N-heterocycles using inexpensive reagents. Expansion of the intramolecular oxidative C(sp3)-H amination to unprotected anilines and amides and C(sp3)-H bonds to occur under mild conditions using t-BuOK, DMF and O2. This protocol relies on a synergy between base, radical and oxidizing species to promote a coordinated sequence of deprotonation followed by H-atom transfer and oxidation that constructs a new C-N bond. We were able to apply this chemistry to the preparation of a wide variety of N-heterocycles, ranging from small molecules to extended aromatics without the need for transition metals or strong oxidants.
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Date Issued: 2018
Identifier: 2018_Sp_Evoniuk_fsu_0071E_14394
Format: Thesis

Title: Modulating Electron Trasnfer Dynamics at Dye-Semiconductor Interfaces.
Creator: Wang, Jamie Chieh-Ming, Hanson, Kenneth G., Liang, Zhiyong, Roper, Michael Gabriel, Schlenoff, Joseph B., Florida State University, College of Arts and Sciences, Department of...
Show moreWang, Jamie Chieh-Ming, Hanson, Kenneth G., Liang, Zhiyong, Roper, Michael Gabriel, Schlenoff, Joseph B., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Electron transfer dynamics at the nanocrystalline semiconducting metal oxide interface plays a pivotal role in diverse applications such as dye-sensitized solar cells (DSSCs), dye-sensitized photoelectric solar cells (DSPECs), sensors and electrochromic thin films. Controlling intermolecular electron transfer at the interface is a critical task, capable of profoundly influencing the efficiency of these applications. Structural control via various physical and chemical design were demonstrated...
Show moreElectron transfer dynamics at the nanocrystalline semiconducting metal oxide interface plays a pivotal role in diverse applications such as dye-sensitized solar cells (DSSCs), dye-sensitized photoelectric solar cells (DSPECs), sensors and electrochromic thin films. Controlling intermolecular electron transfer at the interface is a critical task, capable of profoundly influencing the efficiency of these applications. Structural control via various physical and chemical design were demonstrated to effectively influence the electron transfer rates at these interfaces. Of these approaches, in situ molecular assembly has emerged as an appealing strategy due to the simple preparation to form complex rigid structure that traditionally requires design of one large molecule elaborated with multiple components. In molecular assembly, molecules are adhered to a nanocrystalline metal oxide surface utilizing similar binding motifs and molecular structure-property relationships at the interface to achieve disparate electron transfer dynamics outcomes. In this dissertation, we demonstrated the use of self-assembled bilayer as a scaffold to influence the interfacial electron transfer rates to further our goal of enhancing the productive kinetics while inhibiting the unproductive pathways. By utilizing self-assembled bilayers, we achieved electron transfer modulation while preserving the individual molecule’s electronic structure and property. Chapter 1 is an introductory chapter that lays the foundation of operation principles of DSSCs, electron transfer events at the photoanode, and the physical parameters that govern these processes. Notably, the importance of molecular structural control and a brief history of past approaches are introduced at the end of Chapter 1 as an inspiration for self-assembled bilayers. The remaining chapters take deeper dives into different strategies of varying individual components’ electrochemical properties in order to influence the overall physical properties of the film. We modified the chemical structure of the bridging molecules to influence the electron tunneling rate. For example, Chapters 2 and 3 explore the effect on the electron transfer rate of tuning the distance and energy parameters of bridge molecules by employing self-assembled bilayers. Various properties of the bilayer structure are examined in Chapter 4 and 5, which describe the fundamental studies we have done to investigate role of metal liking ions in the self-assembled bilayers. Together the results in these chapters present an architectural alternative for supramolecular assembly designed to influence electron transfer dynamics in a fully functioning DSSC, and it serves as a foundation for future development of DSSC design.
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Date Issued: 2018
Identifier: 2018_Sp_Wang_fsu_0071E_14322
Format: Thesis

Title: Tailoring Surfaces: From Polyelectrolyte Design to Thin Film Coatings.
Creator: Delgado-Saldarriaga, Jose D. (Jose David), Schlenoff, Joseph B., Keller, Thomas C. S., Hallinan, Daniel T., Kennemur, Justin Glenn, Mattoussi, Hedi, Florida State University,...
Show moreDelgado-Saldarriaga, Jose D. (Jose David), Schlenoff, Joseph B., Keller, Thomas C. S., Hallinan, Daniel T., Kennemur, Justin Glenn, Mattoussi, Hedi, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: The adsorption of proteins in biomedical implants, like catheters, cardiac pacemakers, and blood-contacting sensors,1–3 could cause these devices to malfunction at long term. Therefore, the understanding of proteins’ adsorption onto surfaces is vital in the process of developing new types of biomaterials that exhibit compatibility with human tissue.4,5 Surface modification is the most common route to reduce protein adsorption and cell adhesion, where increasing or converting the...
Show moreThe adsorption of proteins in biomedical implants, like catheters, cardiac pacemakers, and blood-contacting sensors,1–3 could cause these devices to malfunction at long term. Therefore, the understanding of proteins’ adsorption onto surfaces is vital in the process of developing new types of biomaterials that exhibit compatibility with human tissue.4,5 Surface modification is the most common route to reduce protein adsorption and cell adhesion, where increasing or converting the hydrophilicity of the surface has been the overarch. Zwitterionic polymer materials, have developed a renewed interest due to their applicability in high performance anti-fouling coatings. Similarly to polymers containing poly(ethylene glycol), PEG, polyzwitterions, have evolved into a new generation of biomaterials that have the capacity to repel proteins and produce hydrophilic interfaces. Polyelectrolyte multilayers built through the layer-by-layer (LbL) process provides a “library” of surfaces with well-defined charge density and composition. They have been widely studied, showing enormous potential for surface modification, especially because of their capacity to be adjusted to different factors such as salt concentration and pH. This dissertation focuses on tailoring the structure-property relationship of synthesized polyelectrolytes, in a strategic approach to modify the surface of various PEMUs such that they may offer novel properties for biointerface applications. In the first part of this dissertation, a zwitterionic polymer, PAEDAPS, was used to elucidate the behavior and conformation this of poorly-understood and complex type of materials in solution, in response to varying conditions including: ionic strength, salt type and different temperatures. Using dynamic and light scattering methods, salts from the Hofmeister series provided an efficient way to tune polyzwitterion/ion interactions. In salt-free solutions, a fast mode attributed to the transport of waves of linked zwitterionic repeated units in the polymer backbone similarly to those of solitons, was observed. The stimuli-responsive properties of this zwitterionic material make it a potential candidate for future biological applications. After the introduction of zwitterionic polymer materials, which are known to reduce/eliminate both protein adsorption and cell attachment, the following objective was to study the properties of random copolymers with mixtures of carboxylate and sulfonate functionalities or with zwitterionic repeat units on polyelectrolyte multilayers. Here, we explored three questions related to protein and cell adhesion on multilayers in general: first, we established whether there is a correlation between adsorption of bovine serum albumin, and subsequent cell adhesion; second, we evaluated the dependence of protein adsorption and cell adhesion on the type of anionic charge, carboxylate versus sulfonate; third and lastly, we attempted to discover whether there is a dependence of adhesion on the composition of the PEMU just under the “top” layer of added polyelectrolyte. Finally, a versatile approach was developed to make well defined thiolated surfaces for different applications. To this end, a series of random copolymers were used to generate PEMU films containing thiol reactive functional groups. This allowed for the coupling of biomolecules through click chemistry, “grafting-to,” or through simple deposition of pre-grafted polymers, “grafting-from,” methods. For our first application, it was demonstrated that the adhesion of Fibroblast cells can be enhanced by “click” conjugation of RGD peptides to polyelectrolyte multilayer surfaces. In a second pathway, two methods were used to immobilize PEG molecules to PEMUs surfaces: by “clicking” PEG-maleimide directly to thiolated surfaces and by attaching pre-grafted PEG in copolymer polyelectrolytes. And finally, gold nanoparticles (AuNPs) were used to investigate their assembly on the thiol-functionalized PEMUs. Because of the reactivity of the thiol groups in these surfaces, their bio recognition, and selectivity when modified, was demonstrated, proving it to be a solid nanostructured platform with a wide potential for several applications.
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Date Issued: 2018
Identifier: 2018_Sp_DelgadoSaldarriaga_fsu_0071E_14473
Format: Thesis

Title: Controlling Chemical Reactivity with Stereoelectronic Effects.
Creator: dos Passos Gomes, Gabriel, Alabugin, Igor V., Locke, Bruce R., Hanson, Kenneth G., Frederich, James H., Florida State University, College of Arts and Sciences, Department of...
Show moredos Passos Gomes, Gabriel, Alabugin, Igor V., Locke, Bruce R., Hanson, Kenneth G., Frederich, James H., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: This dissertation discloses the work of several research projects involving stereoelectronic effects as a tool to control chemical reactivity. In particular, three areas have been discussed in details: 1. Taming oxygen-rich systems with stereoelectronic effects; 2. Au(I)-Catalyzed Bergman-Cyclization; 3. Isonitriles as stereoelectronic chameleons. Chapter One starts by introducing stereoelectronic effects. In this chapter, I explain how stereoelectronic effects can be studied computationally...
Show moreThis dissertation discloses the work of several research projects involving stereoelectronic effects as a tool to control chemical reactivity. In particular, three areas have been discussed in details: 1. Taming oxygen-rich systems with stereoelectronic effects; 2. Au(I)-Catalyzed Bergman-Cyclization; 3. Isonitriles as stereoelectronic chameleons. Chapter One starts by introducing stereoelectronic effects. In this chapter, I explain how stereoelectronic effects can be studied computationally by defining the tools used throughout this dissertation with definitions and providing examples of their utility. The main quantitative tools for stereoelectronic effects are introduced: conformational changes, reaction equations (such as isodesmic equations), and Natural Bond Orbital (NBO) analysis. The concept of hyperconjugation is explained, with special attention to the role of polarity on the magnitude of these interactions. Chapter Two expands on the role of stereoelectronic effects as a tool to control chemical reactivity by showing examples of how oxygen-rich systems can be tamed. The unusual stability of bis-peroxides contradicts conventional wisdom – some of them can melt without decomposition at temperatures exceeding 100 oC. In this chapter, we disclose a stabilizing stereoelectronic effect that two peroxide groups can exert on each other. This stabilization originates from strong anomeric n_O→σ_(C-O)^* interactions that are absent in mono-peroxides, but reintroduced in molecules where two peroxide moieties are separated by a CH2 group. The two unstable peroxides are transformed into two acetals. The value of stereoelectronic guidelines is illustrated by the discovery of a convenient, ozone-free synthesis of bridged secondary ozonides from 1,5-dicarbonyl compounds and H2O2. The expected tetraoxanes are not formed when the structural distortions imposed on the tetraoxacyclohexane subunit by a three-carbon bridge partially deactivate the anomeric effects, a design projected from our computational endeavors. Finally, we have employed stereoelectronic effects to design a trap for the Criegee Intermediate (CI), the elusive intermediary for the Baeyer-Villiger reaction. Our strategy involved the deactivation of transition-state stabilizing effects for the migratory step via precise cyclic constraints and the usage of the newly-found reverse α-effect. Chapter Three explores the stereoelectronic and zwitterionic assistance in the Au(I)-Catalyzed Bergman Cyclization. With 90% of chemically individual molecules in nature containing a carbo- or heterocyclic subunit, the ability to make cyclic structures in an efficient and selective manner can be paramount to the success of a synthesis. Out of the three main approaches to the formation of cyclic structures (i.e., cyclizations, pericyclic reactions, and cycloaromatizations), cycloaromatization reactions are by far the most unusual and difficult to control. A typical cyclization reaction generally involves a "preformed" high energy reactive center (e.g., a cation, a radical, or an anion) that attacks a weak functionality (e.g., a π-bond) in a process where one bond is formed and the other is broken. In a similar way, the number of bonds is conserved in the classic pericyclic reactions which avoid the formation of unstable intermediates by coordinating the bond-breaking and the bond-forming processes. However, the synergy between bond formation and bond breaking that is typical for pericyclic reactions is lost in their mechanistic cousins, cycloaromatization reactions. In these reactions, exemplified by the Bergman cyclization (BC), two bonds are sacrificed to form a single bond and the reaction progress is interrupted at the stage of a cyclic diradical intermediate. Intrigued by a recent discovery of an unusually fast Au-catalyzed BC, we developed two key tools that allowed us to understand the nature of the catalytic effect: First, we developed a strategy to analyzed the intricate bonding aspects (via NBO analysis) of the two perpendicular π-systems through the course of the reaction; In parallel, we advanced a new theoretical framework for understanding the nature of the catalytic effect by applying the distortion-interaction (DI) analysis to metal-catalyzed reactions. Until then, the widely used DI model was only applied for bimolecular processes. We have shown that our model can provide useful information regarding unimolecular reactions promoted by coordination with a catalyst. Chapter Four dives into the chameleonic behavior of isonitriles facing reactions with radicals. Radical addition to isonitriles (isocyanides) starts and continues all the way to the TS mostly as a simple addition to a polarized pi-bond. Only after the TS has been passed, the spin density moves to the alpha-carbon to form the imidoyl radical, the hallmark intermediate of the 1,1-addition-mediated cascades. Addition of alkyl, aryl, heteroatom-substituted and heteroatom-centered radicals reveals a number of electronic, supramolecular, and conformational effects potentially useful for the practical control of isonitrile-mediated radical cascade transformations. Addition of alkyl radicals reveals two stereoelectronic preferences. First, the radical attack aligns the incipient C⋯C bond with the aromatic pi-system. Second, one of the C-H/C-C bonds at the radical carbon eclipses the isonitrile N-C bond. Combination of these stereoelectronic preferences with entropic penalty explains why the least exergonic reaction (addition of the t-Bu radical) is also the fastest. Heteroatomic radicals reveal further unusual trends. In particular, the Sn radical addition to the PhNC is much faster than addition of the other group IV radicals, despite forming the weakest bond. This combination of kinetic and thermodynamic properties is ideal for applications in control of radical reactivity via dynamic covalent chemistry and may be responsible for the historically broad utility of Sn-radicals ("the tyranny of tin"). In addition to polarity and low steric hindrance, radical attack at the relatively strong pi-bond of isonitriles is assisted by "chameleonic" supramolecular interactions of the radical center with both the isonitrile pi*-system and lone pair. These interactions are yet another manifestation of supramolecular control of radical chemistry.
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Date Issued: 2018
Identifier: 2018_Fall_dosPassosGomes_fsu_0071E_14864
Format: Thesis

Title: Non-Aqueous Electrochemical Studies of Lanthanide and Actiniide Complexes.
Creator: Marsh, Matthew L., Albrecht-Schmitt, Thomas E., Adams, Todd, Hu, Yan-yan, Shatruk, Mykhailo, Florida State University, College of Arts and Sciences, Department of Chemistry and...
Show moreMarsh, Matthew L., Albrecht-Schmitt, Thomas E., Adams, Todd, Hu, Yan-yan, Shatruk, Mykhailo, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: In the 2018 Nuclear Posture Review, it has been emphasized that the continued production of nuclear materials is and will continue to be an essential part of American interest and policy. Necessarily, the cleanup and environmental management of excess nuclear waste, especially from the Cold War era, also continues to be an ongoing effort. For example, just the disposition of legacy plutonium, amounting to 34 MT, is not scheduled to be complete for several decades. The electrochemistry of...
Show moreIn the 2018 Nuclear Posture Review, it has been emphasized that the continued production of nuclear materials is and will continue to be an essential part of American interest and policy. Necessarily, the cleanup and environmental management of excess nuclear waste, especially from the Cold War era, also continues to be an ongoing effort. For example, just the disposition of legacy plutonium, amounting to 34 MT, is not scheduled to be complete for several decades. The electrochemistry of lanthanide and actinide ligand complexes has been studied to various degrees. In some cases, this area has been very understudied. Most of the known coordination complexes are unstudied. Plutonium as an element perhaps presents some of the most interesting redox phenomena, exhibiting up to four oxidation states simultaneously in solution. Later actinides berkelium and californium have very scarce published literature, especially non-aqueous based electrochemistry. Other physical data such as log β and diffusion coefficients are also hard to find for many actinides. The beginning chapters focus on a well-studied ligand, 2,6-pyridinedicarboxylic acid (H2DPA) that has been well-characterized in solid-state methods for the lanthanides and actinides. This ligand has almost exclusively been studied under aqueous conditions, yet for reductive efforts with elements such as Sm, developing a non-aqueous approach was preferred. Detailed solubility investigations are provided, as well as detailed studies with cerium and plutonium, and finally studies with europium and samarium. The next set of chapters deals with later actinide investigations. For reductive electrochemistry with californium, detailed studies with cryptand were developed with the lanthanides. A preferred method was developed that was ultimately used to obtain novel data for californium. In the case of Bk, a pyridyl nitroxide ligand (pyNO) was used to collect the first non-aqueous cyclic voltammogram for this element. Lastly, the final chapter covers a few others systems that were given some efforts. Many of these systems have very interesting electrochemistry, but they were beyond the scope of just one dissertation to complete. These include Schiff bases and DOPO chemistry. The Schiff base data adds insightful data along with the tetravalent chemistry studied in earlier chapters, while the DOPO chemistry covers non-innocent redox phenomena affected by Pu.
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Date Issued: 2018
Identifier: 2018_Fall_Marsh_fsu_0071E_14827
Format: Thesis

Title: Redox and Coordination Chemistry Differences of the 4f and 5f Elements.
Creator: White, Frankie D., Albrecht-Schmitt, Thomas E., Tabor, Samuel L., Hanson, Kenneth G., Hu, Yan-yan, Florida State University, College of Arts and Sciences, Department of...
Show moreWhite, Frankie D., Albrecht-Schmitt, Thomas E., Tabor, Samuel L., Hanson, Kenneth G., Hu, Yan-yan, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: This dissertation seeks to determine the differences in the lanthanides and later actinides in non-aqueous media. Research in the f-elements is significantly understudied compared to the other metals of the periodic table. Even more so are the later actinides which were largely unstudied for an extended period as it was believed later actinides were identical to lanthanides. A review by Neidig et al, “The Covalency in f-element Complexes” has ignited significant interest in the bonding of the...
Show moreThis dissertation seeks to determine the differences in the lanthanides and later actinides in non-aqueous media. Research in the f-elements is significantly understudied compared to the other metals of the periodic table. Even more so are the later actinides which were largely unstudied for an extended period as it was believed later actinides were identical to lanthanides. A review by Neidig et al, “The Covalency in f-element Complexes” has ignited significant interest in the bonding of the actinides.1 A tremendous amount of research in the f-elements, particularly the actinides, has been performed in aqueous conditions at high temperatures and pressures. Chemistry under these conditions limit the research possible for lower oxidation states. Additionally, non-aqueous techniques allow for the investigation of these elements in more organic environments. The goal of this work is to pave a greater understanding of knowledge for lanthanides and actinides by examining their redox and coordination chemistries in these environments that could lead to applications other than nuclear energy and weapons. The first portion of this dissertation examines the chemistry that is already heavily acknowledged about f-elements: coordination chemistry. When modeling later actinides, a common notion is to utilize the isoelectronic lanthanide as the surrogate. Although for electronic comparisons this is useful, it is often not the case for examining isostructural compounds. The isoelectronic lanthanide is often smaller in ionic radius, which is a factor that dominates the chemistry of the lanthanides. Despite this, isolation of isostructural coordination compounds was obtained for the isoelectronic and size analogs of americium; europium and neodymium. This seemingly mundane study showed that americium portrays a small amount of covalency in its bonds which is not observed in the lanthanides. These small differences lead to profound changes in chemical properties as observed later in this work. The second portion of this work focuses on analyzing the divalent oxidation state of f-elements with crown ethers. The divalent oxidation state has been obtained for all lanthanides using potassium and 2.2.2-cryptand. The next step was to determine the extent to which crown ethers and solvents have on the redox properties of f-elements. Because all the lanthanides had been obtained in the divalent oxidation state in a similar matter, it was expected that the redox chemistries would behave identically. To surprise, ytterbium behaves differently and shows greater reversibility than the most stable divalent lanthanide, europium. Additionally, it was found that californium also behaves like ytterbium electrochemically, even though it would be expected to behave like samarium. It was proposed that this may be attributed to the 5f orbitals. The last of this work involves obtaining californium in the divalent oxidation state as a molecular system. This was done by modeling with samarium which is the most similar to californium in its redox and coordination properties. Quick and simple routes to synthesizing divalent samarium structures were obtained in ordinary glovebox conditions for attempts with californium. Under identical reaction conditions, isolation of Cf(II) crystals in the solid state were unsuccessful. However, interesting spectroscopic properties where observed that portrayed divalent californium as having tunable luminescence similar to divalent europium compounds. To our surprise, even though samarium resembles californium, the chemistry between the two elements are very different, further broadening the gap between the 4f and 5f elements.
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Date Issued: 2018
Identifier: 2019_Spring_White_fsu_0071E_14834
Format: Thesis

Title: Ring Opening Metathesis Polymerization of Low Ring Strain Monomers to Investigate Desirable Precision and Structural Properties.
Creator: Brits, Stefan, Kennemur, Justin Glenn, Zhu, Lei, Alabugin, Igor V., Schlenoff, Joseph B., Florida State University, College of Arts and Sciences, Department of Chemistry and...
Show moreBrits, Stefan, Kennemur, Justin Glenn, Zhu, Lei, Alabugin, Igor V., Schlenoff, Joseph B., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: This thesis communicates the research of two projects: the investigation of the structural properties in polycyclododecene and the precision of polypentenamers with highly isotactic branching on every five carbons. High molecular weight polycyclododecene (P_CdDE) is synthesizes using ring opening metathesis polymerization (ROMP) in the presence of a ruthenium catalyst producing moderate dispersity’s. By varying the time of the polymerization, the trans content in the polymer backbone can be...
Show moreThis thesis communicates the research of two projects: the investigation of the structural properties in polycyclododecene and the precision of polypentenamers with highly isotactic branching on every five carbons. High molecular weight polycyclododecene (P_CdDE) is synthesizes using ring opening metathesis polymerization (ROMP) in the presence of a ruthenium catalyst producing moderate dispersity’s. By varying the time of the polymerization, the trans content in the polymer backbone can be controlled. Using this method, a series of P_CdDE polymers were synthesized with trans content ranging from 56 to 70%. We also show that the stereochemistry has a linear influence on the melting temperature. Furthermore, through mechanical testing this polymer showed properties that behaves like a ductile material. A series of allylic substituted cyclopentene monomers with increasing steric bulk are investigated by ring opening metathesis polymerization to understand the effects of these substituents on the microstructural outcomes of the resulting polypentenamers. 3-Triethylsiloxycyclopentene is discovered to polymerize to a highly regular microstructure with up to 96% trans olefins and 92% head-to-tail positional isomers. Dynamic resolution after synthetic modifications produced an enaniopure version (~92% ee) of this monomer which subsequently produced a precision isotactic and regioregular polypentenamer for the first time. Synthetic investigations, mechanistic aspects, and basic thermal properties are discussed.
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Date Issued: 2018
Identifier: 2018_Sp_Brits_fsu_0071N_14551
Format: Thesis

Title: Oxygen Analysis of Complex Petroleum Mixtures by Ultrahigh Resolution Mass Spectrometry.
Creator: Krajewski, Logan Cole, Marshall, Alan G., Zhang, Jinfeng, Bleiholder, Christian, Yang, Wei, Rodgers, Ryan P., Florida State University, College of Arts and Sciences, Department...
Show moreKrajewski, Logan Cole, Marshall, Alan G., Zhang, Jinfeng, Bleiholder, Christian, Yang, Wei, Rodgers, Ryan P., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Petroleum, one of the most complex mixtures on Earth, has been extensively studied for decades. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and the ultrahigh resolution it provides, however, has dramatically transformed our understanding of petroleum by providing detailed molecular characterization. Nevertheless, many properties of crude oil, and the molecular characteristics that drive them, remain poorly understood, especially in regards to the role and impact of...
Show morePetroleum, one of the most complex mixtures on Earth, has been extensively studied for decades. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and the ultrahigh resolution it provides, however, has dramatically transformed our understanding of petroleum by providing detailed molecular characterization. Nevertheless, many properties of crude oil, and the molecular characteristics that drive them, remain poorly understood, especially in regards to the role and impact of oxygen in oils. In the work presented here in-depth characterization of oxygen in petroleum is explored, to augment understanding of petroleum behavior due to oxygen. Although current FT-ICR MS instrument easily provides ultrahigh resolution, there is a constant for more as the complexity of petroleum means there is also some molecule just out of the obtainable analytical reach. Spectral segmenting on petroleum, in which narrow mass windows are acquired instead of all masses at once as in conventional broadband mass spectrometry, was performed in order to increase resolution and dynamic range to explore the species typically “missed” in conventional FT-ICR MS analysis. From the performance improvements provided by spectral segmenting, it was observed that molecules with high heteroatom content, including extensive oxygen content, are observed at low abundances, and that they may play a critical role in petroleum behavior despite their low abundances. Because of this the behavior of oxygen in petroleum is further explored. Naphthenic acids (carboxylic acids) in petroleum are known to be corrosive, yet no known correlation between naphthenic acid content and specific petroleum corrosivity has ever been established, other than more acidic crudes are generally more corrosive. In one proposed corrosion mechanism, a ketone is formed with a structure related to the structure of the corrosive acid. A method to detect and characterize these ketones in petroleum is developed and validated with model acids in an oil matrix, and then applied to more complex mixtures of naphthenic acids and acids derived from a vacuum gas oil to provide insight into which acids are most corrosive. Oxygen in petroleum plays an important role when petroleum is exposed to the environment. FT-ICR MS is used with traditional gas chromatography mass spectrometry (GC/MS) techniques to highlight how it is possible to use oxygen, in addition to other properties and heteroatoms, to track the relation of petroleum as it flows from reservoir to an oil seep and ultimately at the sea surface. In addition to highlighting petroleum subterranean connectivity, an initial characterization is obtained from which information about how petroleum transforms as it migrates is provided. Asphaltenes are perhaps the most poorly understood fraction of petroleum, with their molecular structures under intensive debate. Analysis by high resolution GC/MS of pyrolysis products of “classical” asphaltenes from bitumen and of “environmental” asphaltenes from a tarball is performed. It is found that high resolution is necessary for accurate characterization of even “simple” pyrolysis products, and that environmental asphaltenes are enriched in oxygen relative to the classical bitumen asphaltenes. The exact oxygen structures observe also provides insight into the weathering processes that the tarball underwent in its formation.
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Date Issued: 2018
Identifier: 2018_Sp_Krajewski_fsu_0071E_14290
Format: Thesis

Title: Characterization of Waste-Derived Pyrolysis Oils by Complementary Analysis Techniques.
Creator: Ware, Rebecca Lynn, Marshall, Alan G., Chanton, Jeffrey P., Roper, Michael Gabriel, Dorsey, John G., Strouse, Geoffrey F., Florida State University, College of Arts and Sciences...
Show moreWare, Rebecca Lynn, Marshall, Alan G., Chanton, Jeffrey P., Roper, Michael Gabriel, Dorsey, John G., Strouse, Geoffrey F., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Pyrolysis oil has shown potential as an environmentally-friendly petroleum replacement for the production of fuel and chemicals. Also, the use of waste materials in the production of pyrolysis oil alleviates concerns associated with waste disposal. However, there are still challenges in application of pyrolysis oil as fuel and chemicals due to its convoluted composition and properties that make it incompatible with petroleum. Although analyses have been conducted to explore the composition of...
Show morePyrolysis oil has shown potential as an environmentally-friendly petroleum replacement for the production of fuel and chemicals. Also, the use of waste materials in the production of pyrolysis oil alleviates concerns associated with waste disposal. However, there are still challenges in application of pyrolysis oil as fuel and chemicals due to its convoluted composition and properties that make it incompatible with petroleum. Although analyses have been conducted to explore the composition of pyrolysis oils, complete and in-depth characterizations are required for efficient utilization. The work presented here utilizes chromatographic separations and multiple analysis methods to explore the complexity of pyrolysis oils and the differences between samples. The composition of pyrolysis oil is highly dependent on the material used for production. Plant and food materials (biomass) result in oils that are highly oxygenated causing high acidity and viscosity. Pyrolysis of plastic material results in an oil composed of paraffinic hydrocarbons with low oxygen content. When biomass and plastics are mixed in municipal waste, the pyrolysis oil shows a composition with characteristics of both starting components; lower aromaticity than biomass pyrolysis oils and higher oxygen content than plastic pyrolysis oils. Characterization of these different pyrolysis oils requires complementary, targeted analyses for complete coverage of all compositions in each unique sample. The high resolution and mass accuracy of Fourier transform ion cyclotron resonance mass spectrometry provides elemental formulas for the thousands of components within a pyrolysis oil. This method is particularly useful for the polar and high molecular weight species that are not compatible with gas chromatography. In contrast, gas chromatography is beneficial for the analysis of volatile components and provides structural information based on retention time. Infrared spectroscopy provides bulk functional information of an oil, and is especially helpful in identifying oxygen functionalities. To further explore the complexity of pyrolysis oils, solid phase extractions reduce complexity and allow for analysis of targeted chemistries without interference. Extractions also provide functional information based on the interaction of species within the sample with the stationary phase. Combination of methods in the analysis of both biomass- and municipal waste-derived pyrolysis oils provides a molecular level understanding of their compositions and properties, illuminating efficient applications for these oils.
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Date Issued: 2018
Identifier: 2018_Sp_Ware_fsu_0071E_14440
Format: Thesis

Title: Taming and Tuning Multistate Fluorophores for White-Light Emitting Materials.
Creator: Meisner, Quinton J. (Quinton James), Zhu, Lei, Guan, Jingjiao, Hanson, Kenneth G., Kennemur, Justin Glenn, Miller, Brian G, Florida State University, College of Arts and...
Show moreMeisner, Quinton J. (Quinton James), Zhu, Lei, Guan, Jingjiao, Hanson, Kenneth G., Kennemur, Justin Glenn, Miller, Brian G, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Contained is work conducted for the purposes of creating a single molecule white-light emitter. The efforts include the synthesis and characterization of a number of multistate fluorophores that can either undergo an Excited-State Intramolecular Proton Transfer (ESIPT) or a Charge-Transfer (CT) emission mechanism. In addition, all title compounds studied were sensitive to basic species and generated phenolate like species with distinct emission profiles from their parent phenol like forms. To...
Show moreContained is work conducted for the purposes of creating a single molecule white-light emitter. The efforts include the synthesis and characterization of a number of multistate fluorophores that can either undergo an Excited-State Intramolecular Proton Transfer (ESIPT) or a Charge-Transfer (CT) emission mechanism. In addition, all title compounds studied were sensitive to basic species and generated phenolate like species with distinct emission profiles from their parent phenol like forms. To fully understand the fluorophores of the 2-(2-hydroxyphenyl)benzoxazole (HBO) and 1,4-substituted-1,2,3-trazole varieties, and their potential in a material applications visual spectroscopy was employed (UV-vis, fluorescence, quantum yield, and CIE 1931 coordinates). The results for dyes derived from the 1,4-substituted-1,2,3-triazole structures were found to contain interesting CT behavior and photo switching upon addition of base but were shown to lack an emissive ESIPT mechanism. Dyes derived from the HBO structures contained significant solvatochromic shifts from ~420 nm (blue) to ~550 nm (yellow) in the neutral forms. Quantum yields were found up to 0.35 and CIE 1931 coordinates close to the value for ideal white-light with values at around (0.31, 0.32). The phenolate derivatives were found to be mostly monochromatic with high quantum yields from 0.20 – 0.80.
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Date Issued: 2018
Identifier: 2018_Su_Meisner_fsu_0071E_14671
Format: Thesis

Title: Application of FT-ICR Mass Spectrometry in Hydrogen Deuterium Exchange and Lipidomics.
Creator: Liu, Peilu, Marshall, Alan G., Tang, Hengli, Dorsey, John G., Miller, Brian G, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
Abstract/Description: High resolution mass spectrometry, especially Fourier transform ion cyclotron resonance mass spectrometry (FT ICR MS) is a widely practiced technique of choice in proteomics and lipidomics due to its high sensitivity, reproducibility and wide dynamic range. FT-ICR MS enables quick assignments of hundreds of peptides and lipids with extreme complexity. Chapter 1 introduces the fundamental of FT ICR phenomena for mass measurement and basic theories of LC-MS based hydrogen deuterium exchange ...
Show moreHigh resolution mass spectrometry, especially Fourier transform ion cyclotron resonance mass spectrometry (FT ICR MS) is a widely practiced technique of choice in proteomics and lipidomics due to its high sensitivity, reproducibility and wide dynamic range. FT-ICR MS enables quick assignments of hundreds of peptides and lipids with extreme complexity. Chapter 1 introduces the fundamental of FT ICR phenomena for mass measurement and basic theories of LC-MS based hydrogen deuterium exchange (HDX) technique for high order structure studies. Chapter 1 also introduces the application of mass spectrometry in lipidomics including lipid classification and MS analysis. Chapter 2 described the characterization of the binding interfaces in R2TP complex by hydrogen/deuterium exchange mass spectrometry. The two closely related AAA+ family ATPase Rvb1 and Rvb2 form a tight functional complex with two Hsp90 interactors: Pih1p and Tah1p. The R2TP complex involves in multiple biological processes including apoptosis, PIKK signaling, and RNA polymerase II assembly, and snoRNP biogenesis. The current lack of structural information on R2TP complex prevents a mechanistic understanding of many biological processes. By use of solution-phase HDX MS, we probed the contact surfaces on Pih1p-Tah1p upon Rvb1/2p binding. The present results demonstrate that Pih1p-Tah1p interacts with Rvb1/2p through N-terminal and IDR2 regions of Pih1p. Significantly, HDX also detected a rearrangement of residues 38–60 of Pih1p and 1–44 of Tah1p upon formation of the R2TP complex. Chapter 3 depicts the study of conformations of activated, disease-associated glucokinase variants by a comparative hydrogen/deuterium exchange mass spectrometry. Human glucokinase (GCK) acts as the body’s primary glucose sensor and plays a critical role in glucose homeostatic maintenance. Previous biochemical and biophysical studies suggest the existence of two activated variants. HDX results demonstrate that a disordered active site, which is folds upon binding of glucose, is protected from exchange in α helix variant. Additionally, α helix variant displays an increased level of exchange near enzyme’s hinge region. In contrast, β hairpin variant does not show substantial difference in global or local exchange relative to that of wild type GCK. The work elucidates the structural and dynamics origins of GCK’s unique kinetic cooperativity. Chapter 4 investigated the structure of an antibody with ‘Knob-into-hole’ mutations by HDX MS. Bispecific antibodies (BsAbs) have flourished in the biopharmaceutical industry for targeting two distinct antigens simultaneously. ‘Knob-into-hole’ approach is a way to manufacture bispecific antibodies. The applicability and advantage of ‘Knob-into-hole’ engineered bispecific antibody is vast. However, concerns about the conformational change and immunogenicity risks posed by the new approach has have been raised. To better understand the conformations and dynamics impacted by the ‘knob’ and ‘hole’ mutations, HDX MS is used to characterize peptide-level conformational changes of a ‘Knob-into-hole’ engineered antibody. The study shows that there is no significant structural alternation induced by ‘Knob-into-hole’ framework. In Chapter 5, the applicability of resolving HDX-derived isotopic fine structure by ultrahigh resolving power FT ICR mass spectrometry was discussed. In an HDX experiment, labeling protein with deuterium causes the deuterium incorporation, resulting in distributions of various combinations of 13C1H and 12C2H (Δm = 2.9 mDa). The isotopic fine structure typically cannot be used to evaluate deuteration level due to the difficulty of .resolving fine structures for all proteolytic peptides spanning wide mass range from HDX experiments. The introduction of hexapolar cell triples the observed resolving power on 14.5 tesla FT-ICR mass spectrometer, thus we successfully extend the capability of resolving isotopic fine structure to most of identified peptides. Additionally, a new method of analysis of isotopic fine structure-resolved HDX data was proposed to determine degrees of deuterium incorporation. Another research area I have worked on is characterization of polar lipids by LC coupled with FT-ICR mass spectrometry. Algae lipids contain long-chain saturated and polyunsaturated fatty acids. The lipids may be transesterified to generate biodiesel fuel. In Chapter 6, I compared polar lipid compositions for two microalgae, Nannochloropsis oculata and Haematococcus pluvialis, that are prospective lipid-rich feedstock candidates for an emerging biodiesel industry. Online nano liquid chromatography coupled with negative electrospray ionization 14.5 T Fourier transform ion cyclotron resonance mass spectrometry ((−) ESI FT-ICR MS) with newly modified ion optics provides ultrahigh mass accuracy and resolving power to identify hundreds of unique elemental compositions. Assignments are confirmed by isotopic fine structure for a polar lipid extract. Collision-induced-dissociation (CID) MS/MS provides additional structural information. H. pluvialis exhibits more highly polyunsaturated lipids than does N. oculata.
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Date Issued: 2018
Identifier: 2018_Su_Liu_fsu_0071E_14651
Format: Thesis

Title: Nano-Biosensors: Probing Intracellular Response to Nanoparticle Therapy.
Creator: Carnevale, Katelyn J. F. (Katelyn Jo Fredrickson), Strouse, Geoffrey F., Levenson, Cathy W., Schlenoff, Joseph B., Yang, Wei, Florida State University, College of Arts and...
Show moreCarnevale, Katelyn J. F. (Katelyn Jo Fredrickson), Strouse, Geoffrey F., Levenson, Cathy W., Schlenoff, Joseph B., Yang, Wei, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Nanoparticle based cellular therapies hold great promise for clinical applications and medicinal use in human patients by allowing for targeted delivery of a personalized medicine payload to specific cells and tissues in a variety of disease states. The large surface to volume ratio of solid inorganic nanoparticles and the availability of facile surface functionalization chemistries with gold, gold-coated, and semi-conductor nanoparticles enables the design of delivery agents which can...
Show moreNanoparticle based cellular therapies hold great promise for clinical applications and medicinal use in human patients by allowing for targeted delivery of a personalized medicine payload to specific cells and tissues in a variety of disease states. The large surface to volume ratio of solid inorganic nanoparticles and the availability of facile surface functionalization chemistries with gold, gold-coated, and semi-conductor nanoparticles enables the design of delivery agents which can simultaneously carry a targeting molecule, such as an antibody or cell penetrating peptide (CPP), a short oligonucleotide for RNA interference or intracellular sensing, and a full gene for genetic therapy to correct aberrant protein function or cause apoptosis of cancer cells. The scope of applicability for nano-therapy technology is incalculable, however current understanding of the intracellular uptake and processing of nanomaterials-based therapeutics is limited and many facets of the cellular response to nanoparticle therapy are still in need of investigation. The goal of this dissertation work has been to elucidate the effects of nanoparticle-based therapeutics to ascertain the intracellular fate and processing of model nanomedicines by designing nanoparticle-bioconjugates capable of spatiotemporally reporting live intracellular uptake and processing events using fluorescence microscopy, and magnetic detection. The first chapter gives an introduction to nanoparticles and their use in biological applications, as well as detailing how they can be used as intracellular sensors. The second chapter investigates the ability to control therapeutic DNA cargo release from a gold nanoparticle in live cells using different appendage chemistries. The third chapter probes the intracellular environment experienced by the nanotherapeutic and discusses nano-induced effects to the intracellular environment. The fourth chapter investigates nanotherapy cellular uptake targeting using cell penetrating peptides, as probed by fluorescent quantum dots, to determine outcomes for a variety of naïve and drug resistant mammalian cell lines, include human lung, skin and brain cancers as well as rodent cancer model cell lines. The fifth chapter combines optical and magnetic analysis techniques to investigate multiplexed sensing with gold shelled iron oxide nanoparticles to investigate cellular uptake. And the last chapter summarizes the work and provides a discussion of the outlook for the work.
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Date Issued: 2018
Identifier: 2018_Su_Carnevale_fsu_0071E_14533
Format: Thesis

Title: Microwave Effects on Homogeneous Claisen Rearrangement and Heterogeneous Catalyzed Hydroalkoxylation.
Creator: Gagnier, Joshua Paul, Stiegman, Albert E., Telotte, John C., Strouse, Geoffrey F., Zhu, Lei, Florida State University, College of Arts and Sciences, Department of Chemistry and...
Show moreGagnier, Joshua Paul, Stiegman, Albert E., Telotte, John C., Strouse, Geoffrey F., Zhu, Lei, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: The use of microwaves as an alternative heating source has been growing for the past few decades. The utility as a rapid heating tool is known, but the overall impacts on chemistry and synthesis, still needs to be investigated. With growing reports of observed selective microwave effects, further understanding is required. This study investigates the use of additives both homogeneous and heterogeneous, and their impacts on synthetic microwave chemistry compared to traditional convective...
Show moreThe use of microwaves as an alternative heating source has been growing for the past few decades. The utility as a rapid heating tool is known, but the overall impacts on chemistry and synthesis, still needs to be investigated. With growing reports of observed selective microwave effects, further understanding is required. This study investigates the use of additives both homogeneous and heterogeneous, and their impacts on synthetic microwave chemistry compared to traditional convective heating. The aryl-Clasien rearrangement is a well-studied unimolecular [3+3] sigmatropic rearrangement. Its use through out synthetic organic chemistry makes it a good candidate to study selective microwave heating. Here we investigated the addition of a chaperone molecule, in which a non-reactive but highly absorbing additive added the rearrangement under microwave irradiation but showed almost no improvement under conventional heating at comparable temperatures. Hydroalkoxylation is the reaction of an alcohol with either an alkene or alkyne to produce ethers. Recently, our group was studying the heterogeneous catalyzed aryl Claisen rearrangement of allyl phenyl ether, when the use of spinels as a catalyst afforded the 2-methylcoumaran as a byproduct. Under microwave conditions this byproduct was formed in higher yields when compared to that of the oil bath. It was then observed that the hydroalkoxylation of the 2-allylphenol produced the coumaran at a faster rate under microwave heating than conventional heating. In this study we investigated the utility of the spinel catalyzed hydroalkoxylation. Magnetite afforded the greatest conversion to the desired products in moderate to high yields.
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Date Issued: 2018
Identifier: 2018_Su_Gagnier_fsu_0071E_14431
Format: Thesis

Title: Structure and Dynamics of Polyelectrolyte Multilayers and Complexes.
Creator: Fares, Hadi M., Schlenoff, Joseph B., Keller, Thomas C. S., Steinbock, Oliver, Strouse, Geoffrey F., Florida State University, College of Arts and Sciences, Department of...
Show moreFares, Hadi M., Schlenoff, Joseph B., Keller, Thomas C. S., Steinbock, Oliver, Strouse, Geoffrey F., Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Polyelectrolyte complexes (PECs) are made by mixing oppositely charged polymers. In this dissertation, a pair of pH-independent polyelectrolytes was used: a polycation, poly(diallyldimethylammonium), PDADMA, and a polyanion, poly(styrenesulfonate), PSS. Different morphologies of complexes can be obtained depending on the preparation technique. Polyelectrolyte multilayers, PEMUs, are formed by alternately depositing “layers” of oppositely charged polymers on different surfaces, while...
Show morePolyelectrolyte complexes (PECs) are made by mixing oppositely charged polymers. In this dissertation, a pair of pH-independent polyelectrolytes was used: a polycation, poly(diallyldimethylammonium), PDADMA, and a polyanion, poly(styrenesulfonate), PSS. Different morphologies of complexes can be obtained depending on the preparation technique. Polyelectrolyte multilayers, PEMUs, are formed by alternately depositing “layers” of oppositely charged polymers on different surfaces, while traditional complexes are produced by solution precipitation of the dissolved polyelectrolytes. A plethora of applications have been proposed for these polymeric materials, from antibacterial coatings, to electronic devices, and drug reservoirs. Doping the PEC refers to adding a certain concentration of salt to the material, causing many polymer/polymer interactions, known as intrinsic sites, to turn into polymer/counterion interactions, or extrinsic sites. The doping level is usually determined by the salt type and concentration, as well as the polymer pair. This work can be divided into two large sections. The dilemma at the center of the first one was an excess of one polyelectrolyte in as-made PEMUs – PDADMA in this case. This created an imbalance and brought extra ions in the film rendering it unpredictable for applications. The solution was to cycle the film between 2 M NaCl and PSS, the missing polyanion, in 1 M NaCl to compensate for the excess polycation. The technique turned PEMUs into stoichiometric, ion-free, and exceedingly smooth films. With this homogeneous PEC film at hand, the next steps aimed at understanding the reasons that lead to the properties of the original multilayer. The two main targets were to elucidate the overcompensation or overcharging behavior of polyelectrolytes in these complexes, and their kinetics. Long known as the driving force behind the growth of these layered systems, overcompensation had not been previously extensively explored. Both polyelectrolytes were separately added to the stoichiometric films, and the amount of excess was monitored using radiolabeling and Fourier transform infrared spectroscopy, FTIR. Independently from the polymer nature, concentration, molecular weight (to a certain extent), and the film thickness, the overcompensation limit was around 40%. Calculations showed that this maximum is related to the breakdown of a Donnan equilibrium that forms during the addition of the polyelectrolytes to the PEC. A slight dependence of this value on the salt concentration hinted at the second target of this study: the kinetics of polyelectrolytes. Through the same techniques, and using deuterated polymers in FTIR, the transport of species within the PEC was monitored over time. Site-diffusion, or the movement of counterions from one excess site to another, revealed by radioactive labeling, was around three orders of magnitude faster than polymer diffusion, shown by the deuterated polymer moving throughout a protiated film, or vice versa (protiated polymer in deuterated film). Moreover, site-dominated diffusion was closer to the timescale of the multilayering procedure. The information obtained from reaching these two targets allowed us to tailor PEMU growth to obtain different thicknesses and buildup regimes. In the second main section, the internal structure of the polyelectrolyte complex/coacervate continuum, accessed by the doping of the solid complex with increasing concentrations of KBr, was probed using small-angle neutron scattering, SANS. Deuterated PSS inserted at a proper concentration within the protiated PEC exhibits a detectable contrast in this technique. The chain maintained its radius of gyration in the solid samples, but decreased slightly in size in the phase-separated coacervate and liquid samples. In KBr solutions, the decrease in the macromolecule’s size was sharper, as revealed by light scattering, suggesting that the chain behavior in the PEC is under opposing forces. On one hand, the network volume increase promotes polymer extension. On the other hand, higher salt concentrations induce what is known as the polyelectrolyte effect, shrinking the polymer. The result is a coiled chain throughout the continuum. Pores in the solid regime were also observed and the reason behind their presence was explored. These pores were more thoroughly investigated in a second study that focused on the long-term swelling behavior in extruded PEC fibers. The material exhibited significant swelling, and porosity, in solutions with an NaCl concentration below 0.01 M. Osmotic pressure was quantified inside and outside the polymer network, and exposed as the culprit behind this comportment. PECs were also shown to swell more in a range of polar solvents that have a small molecule size. These investigations of the shape and mobility of charged polymers within their complexes provide a better understanding of their often-puzzling behavior. They also serve as a starting point for studies that can benefit from this knowledge to build better materials.
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Date Issued: 2018
Identifier: 2018_Su_Fares_fsu_0071E_14659
Format: Thesis

Title: Applications of 21 Tesla FT-ICR Top-down Proteomics in Clinical Research and Diagnosis.
Creator: He, Lidong, Marshall, Alan G., Tang, Hengli, Dorsey, John G., Hu, Yan-yan, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
Abstract/Description: With recent progress in clinical proteomics, mass spectrometry (MS)-based methods have been widely implemented in diagnosis of diseases which offers high specificity that conventional clinical tests lack. The recent development of high resolution high mass accuracy mass spectrometry leads to full characterization of intact proteins (e.g., therapeutic monoclonal antibodies and endogenous protein biomarkers) in a top-down MS/MS fashion. Top-down MS/MS offers “birds’ eye” view of the proteins...
Show moreWith recent progress in clinical proteomics, mass spectrometry (MS)-based methods have been widely implemented in diagnosis of diseases which offers high specificity that conventional clinical tests lack. The recent development of high resolution high mass accuracy mass spectrometry leads to full characterization of intact proteins (e.g., therapeutic monoclonal antibodies and endogenous protein biomarkers) in a top-down MS/MS fashion. Top-down MS/MS offers “birds’ eye” view of the proteins and yields more confident protein sequence assignment and post-translational modifications localization. This dissertation describes the latest top-down applications in disease precision diagnosis that can potentially lead to future personalized treatment. Chapter 2 describes a pilot study for characterization of monoclonal antibodies by top-down and middle-down approaches with the advantages of fast sample preparation with minimal artifacts, ultrahigh mass accuracy, and extensive residue cleavages by use of 21 tesla FT-ICR MS/MS. The ultrahigh mass accuracy yields an rms error of 0.2–0.4 ppm for antibody light chain, heavy chain, heavy chain Fc/2, and Fd subunits. The corresponding sequence coverages are 81%, 38%, 72%, and 65% with MS/MS rms error ~4 ppm. Extension to a monoclonal antibody in human serum as a monoclonal gammopathy model yielded 53% sequence coverage from two nano-LC MS/MS runs. A blind analysis of five therapeutic monoclonal antibodies at clinically relevant concentrations in human serum resulted in correct identification of all five antibodies. Nano-LC 21 T FT-ICR MS/MS provides nonpareil mass resolution, mass accuracy, and sequence coverage for mAbs, and sets a benchmark for MS/MS analysis of multiple mAbs in serum. This is the first time that extensive cleavages for both variable and constant regions have been achieved for mAbs in a human serum background. Chapter 3 describes a novel protein de novo sequencing method given that top-down MS/MS complete sequence coverage is virtually impossible. To characterize the “AA sequence gap” between two adjacent fragments, the number of gap AA sequences with identical masses for di-, tri-, and tetra-AA gaps grows exponentially with increasing number of gap amino acids. If peptide fragment mass could be measured exactly (in practice, to 0.00001 Da), it would then be possible to define the overall atomic composition for the group of amino acids spanning a product ion gap 3-4 amino acids long. I show that de novo top-down/middle-down MS/MS can determine the germline sequence category for a given monoclonal antibody and further serve to identify its novel mutations. Chapter 4 applies my developed top-down protein de novo sequencing in characterization of serum monoclonal immunoglobulins from plasma cell disorders. The current five-year survival rate for systemic AL amyloidosis or multiple myeloma is below 50%, indicating the urgent need for better diagnosis methods and treatment plans. Unlike genomic testing, which requires bone marrow aspiration and may fail to identify all monoclonal immunoglobulins produced by the body, the present method requires only a blood draw. In addition, circulating monoclonal immunoglobulins spanning the entire population are analyzed and reflect the selection of germline sequence by B cells. The monoclonal immunoglobulin light chain FR2-CDR2-FR3 was sequenced by de novo MS/MS and 100% matched the gene sequencing result except for two amino acids with isomeric counterparts, enabling accurate germline sequence classification. This work represents the first application of top/middle-down MS/MS for de novo sequencing of endogenous monoclonal immunoglobulins with polyclonal immunoglobulins background. Chapter 5 is focused on top-down MS/MS diagnosis of hemoglobin disorders. Hemoglobinopathies and thalassemias are the most common genetically determined disorders. Current diagnosis methods include cation exchange high performance liquid chromatography and electrophoresis for screening whose results can be ambiguous because of limited resolving power, and expensive and laborious genetic testing is needed for confirmation. I developed a top-down MS/MS approach with the advantages of fast data acquisition (3 min), ultrahigh mass accuracy, and extensive residue cleavages by use of 21 tesla FT-ICR MS/MS for hemoglobin variant sequence de novo characterization and thalassemia diagnosis. With my developed generic approach for hemoglobin variant de novo sequencing, all eighteen hemoglobin variants were correctly identified in blind analysis which include the first characterization of homozygous hemoglobin Himeji variant. It is the first time that the abundance ratio between intact δ and β subunits (δ/β) is used for beta thalassemia (including beta thalassemia trait/major) screening. Therefore, 21 T FT-ICR MS sets the benchmark for top-down MS/MS analysis of hemoglobin variants and thalassemia.
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Date Issued: 2018
Identifier: 2018_Su_He_fsu_0071E_14616
Format: Thesis

Title: Developing Trapped Ion Mobility Spectrometry as a Tool for the Structural Elucidation of Biological Compounds.
Creator: Kirk, Samuel Robert, Bleiholder, Christian, Landing, William M., Marshall, Alan G., Shatruk, Mykhailo, Florida State University, College of Arts and Sciences, Department of...
Show moreKirk, Samuel Robert, Bleiholder, Christian, Landing, William M., Marshall, Alan G., Shatruk, Mykhailo, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: One of the grand challenges in the field of human health is to understand the structure-function relationship of biological molecules. To date, there exist many types of low and high resolution methods for interrogating the structure of biological monomeric and assembly systems. No one structural technique is up to the challenge in elucidating the detailed three dimensional structure of every analyte of interest. A culmination of structural data collected by an assortment of methods is the...
Show moreOne of the grand challenges in the field of human health is to understand the structure-function relationship of biological molecules. To date, there exist many types of low and high resolution methods for interrogating the structure of biological monomeric and assembly systems. No one structural technique is up to the challenge in elucidating the detailed three dimensional structure of every analyte of interest. A culmination of structural data collected by an assortment of methods is the only approach in overcoming the diverse limitations that inevitably plague each technique. Ion mobility mass spectrometry (IMS-MS) certainly occupies an area in the spectrum of structural elucidation platforms. IMS-MS has certain advantages other techniques that make it a powerful tool for studying the structure of biological complexes. Trapped ion mobility spectrometry (TIMS) is a recently developed and commercialized high resolution ion mobility technique. TIMS as a new method must be validated in its ability to probe the biologically relevant structures of biological molecules and their assemblies. My work in the Bleiholder lab began with working on a project that showed for the first time that native like conformers of the protein ubiquitin could be retained during the course of a TIMS analysis. The remainder of this document seeks to continue to develop TIMS as a useful tool for structural biology. Chapter one gives a brief and general overview of some of the structural methods available to date, and presents some of the details related to ion mobility and TIMS. Chapter two shift from preserving monomeric to multimeric systems in TIMS. We show there that inadvertent fragmentation leading to structural artefacts can be overcome. Chapter three shows as a proof of concept that tandem-TIMS can perform CID of proteins up to ~18 kDa. We show that TIMS-CID-TIMS can not only provide sequence coverage similar to other mass spectrometry platforms, but that it also can sample conformational differences between fragments of the same m/z ratio. Chapter four exhibits the ability of tandem-TIMS to thermally unfold the protein ubiquitin in the electrospray source. Chapter 5 seeks to characterize the trapping efficiency of the TIMS analyzer and shows ions can be retained for upwards of 15 seconds. Finally chapter six provides a conclusion and future direction. Additional details in the aforementioned chapters are found in the appendices.
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Date Issued: 2018
Identifier: 2018_Su_Kirk_fsu_0071E_14754
Format: Thesis

Title: Nanoparticle-Electromagnetic Radiation Interaction: Implications and Applications.
Creator: Vakil, Parth Nalin, Strouse, Geoffrey F., Ramakrishnan, Subramanian, Schlenoff, Joseph B., Zhu, Lei, Florida State University, College of Arts and Sciences, Department of...
Show moreVakil, Parth Nalin, Strouse, Geoffrey F., Ramakrishnan, Subramanian, Schlenoff, Joseph B., Zhu, Lei, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Nanotechnology is a new frontier for the advancement of science and technology. Nanomaterials are playing a crucial role and that they will continue to do so is beyond doubt. They are being used in electronic, magnetic, optical and catalytic applications where the unique interactions of nanostructured materials with electromagnetic radiation is of great benefit. While significant progress in understanding fundamental nanoparticle - electromagnetic radiation interactions has been made, and has...
Show moreNanotechnology is a new frontier for the advancement of science and technology. Nanomaterials are playing a crucial role and that they will continue to do so is beyond doubt. They are being used in electronic, magnetic, optical and catalytic applications where the unique interactions of nanostructured materials with electromagnetic radiation is of great benefit. While significant progress in understanding fundamental nanoparticle - electromagnetic radiation interactions has been made, and has improved practical technology applications, there is plenty left to be fully understood. This dissertation aims to further probe nanoparticle - electromagnetic radiation interactions and unveil details previously not known. More specifically, this dissertation looks at how microwaves can aid in the synthesis of anisotropic magnetic nickel nanoparticles, how small sized nanoparticles can be used in tuning the dielectric properties of polymer-nanocomposites, and how core-shell nanoparticles can be used for high quenching of fluorescence red dyes. An overview of chapters section that provides a more detailed content summary for each chapter is found at the end of the introduction chapter.
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Date Issued: 2018
Identifier: 2018_Su_Vakil_fsu_0071E_14743
Format: Thesis

Title: Magnetic and Spectroscopic Properties of Fe³⁺ and Mn²⁺ Doped in Model Quantum Dots.
Creator: Bindra, Jasleen Kaur, Dalal, Naresh S., Chiorescu, Irinel, Strouse, Geoffrey F., Steinbock, Oliver, Florida State University, College of Arts and Sciences, Department of...
Show moreBindra, Jasleen Kaur, Dalal, Naresh S., Chiorescu, Irinel, Strouse, Geoffrey F., Steinbock, Oliver, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: This dissertation is focused on the study of a series of paramagnetic materials from molecular to nanoscale with increasing number of transition metal ions. We have successfully used techniques like SQUID magnetometry, high frequency electron paramagnetic resonance (HFEPR) and magic angle spinning nuclear magnetic resonance (MAS NMR) to characterize series of samples. Initial work of this dissertation was focused on the molecular systems and its major part is dedicated to the study of...
Show moreThis dissertation is focused on the study of a series of paramagnetic materials from molecular to nanoscale with increasing number of transition metal ions. We have successfully used techniques like SQUID magnetometry, high frequency electron paramagnetic resonance (HFEPR) and magic angle spinning nuclear magnetic resonance (MAS NMR) to characterize series of samples. Initial work of this dissertation was focused on the molecular systems and its major part is dedicated to the study of transition ion doped Quantum Dots (QDs). The molecular systems discussed here are as follows: Vanadyl Phthalocyanine (VOPc), [H3M3+2(As3+W6O23)2(As3+O3)2]11- (M = Cr3+, Fe3+) and [H3Mn2+2(As3+W6O21)2(As3+O3)4]11-, X2Cr(dpa)4Cl2, (X = Cr, Mo and W), [M4(OH)2(H2O)2(α-SiW10O37)2]14- (M = Co2+, Ni2+, Zn2+). Following are the QDs samples: Fe3+ Doped ZnSe QDs, (Fe:ZnSe), Fe3+ Doped CdSe QDs, (Fe:CdSe), Mn2+ Doped ZnSe QDs, (Mn:ZnSe) and Al3+ Doped ZnSe QDs, (Al:ZnSe). Chapter 1 gives the motivation, overview and organization of this dissertation. Chapter 2 describes the techniques used in this undertaking. Chapter 3 is focused on molecular systems: Vanadyl Phthalocyanine (VOPc), [H3M3+2(As3+W6O23)2(As3+O3)2]11- (M = Cr3+, Fe3+) and [H3Mn2+2(As3+W6O21)2(As3+O3)4]11-, X2Cr(dpa)4Cl2, (X = Cr, Mo and W), [M4(OH)2(H2O)2(α-SiW10O37)2]14- (M = Co2+, Ni2+, Zn2+). Chapter 4-7 are focused on the nanoscale quantum dots samples. Chapter 4 describes correlation of structure and observed magnetic properties of local inclusions formed upon doping Fe3+ in ZnSe QDs. Chapter 5 reports probing dynamics of Mn2+ in ZnSe QDs using high frequency pulsed EPR spectroscopy. Origin of ferromagnetic and antiferromagnetic interactions in Fe3+ doped CdSe QDs is discussed in Chapter 6. Chapter 7 describes the use of MAS NMR in probing local sites Al3+ dopant in ZnSe QDs. Finally, Chapter 8 summarizes the major results and conclusions of this dissertation.
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Date Issued: 2018
Identifier: 2018_Fall_Bindra_fsu_0071E_14968
Format: Thesis

Title: Radical Reactions to Form Expanded Polyaromatics: Electronic and Steric Control.
Creator: Hughes, Audrey Marie, Alabugin, Igor V., Locke, Bruce R., Hanson, Kenneth G., Yang, Wei, Florida State University, College of Arts and Sciences, Department of Chemistry and...
Show moreHughes, Audrey Marie, Alabugin, Igor V., Locke, Bruce R., Hanson, Kenneth G., Yang, Wei, Florida State University, College of Arts and Sciences, Department of Chemistry and Biochemistry
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Abstract/Description: Cascade radical transformations of acyclic precursors that incorporate alkynes open efficient, convenient, and atom-economical access to functionalized compounds. The selective sequence of cyclizations followed by controlled termination offer products of increased structural complexity. First, selectivity of initiation can be guided either by steric and geometric constraints, a tethered initiator, or through a directing group, such as an alkoxy group, placed near the desired point of attack....
Show moreCascade radical transformations of acyclic precursors that incorporate alkynes open efficient, convenient, and atom-economical access to functionalized compounds. The selective sequence of cyclizations followed by controlled termination offer products of increased structural complexity. First, selectivity of initiation can be guided either by steric and geometric constraints, a tethered initiator, or through a directing group, such as an alkoxy group, placed near the desired point of attack. These methods ensure attack at the correct carbon of the central alkyne, the necessary point of initiation to result in a fully cyclized alkyne substrate. Second, reduction of geometric "defects" has been previously achieved by introducing a skipped carbon in the oligoalkyne starting material. By designing a directing group that also fragments upon the completion of the cascade, the alkyl loop left over from tethered initiation has been eliminated. Third, termination cyclizations are further optimized by the use of peri- attack at the zigzag edge of a strategically placed polyaromatic unit. When the vinyl radical present after initiation of the reaction is produced, a hexagon is will be formed as a result of the next step rather than a previously present pentagon from attack at a pendant phenyl group. However, such peri- attack approaches introduce additional complexity in that there is now stereoelectronic interactions between the directing group and Sn that were not previously necessary to consider.
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Date Issued: 2018
Identifier: 2018_Fall_Hughes_fsu_0071E_14878
Format: Thesis

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