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Reticular Synthesis Of Metal-Organic Rotaxane Frameworks, Alexander Joseph Stirk
Reticular Synthesis Of Metal-Organic Rotaxane Frameworks, Alexander Joseph Stirk
Electronic Theses and Dissertations
The work herein, describes the placement of mechanically interlocked molecules (MIMs) into ordered, crystalline metal-organic frameworks (MOFs) to create metal-organic rotaxane frameworks (MORFs). This placement is done through the use of the concepts of reticular synthesis, to create predictable materials based on prior known building blocks and topological nets in order to achieve robust dynamics. The concepts of MIMs, nets, reticular synthesis, robust dynamics are all discussed in detail in Chapter 1. Also outlined in Chapter 1 are six design criteria that act as a blueprint for the creation of robust dynamics using the tenants of reticular synthesis. Chapter 2 …
Solid-State Nmr Spectroscopy Of Unreceptive Nuclei In Inorganic And Organic Systems, Hiyam Hamaed
Solid-State Nmr Spectroscopy Of Unreceptive Nuclei In Inorganic And Organic Systems, Hiyam Hamaed
Electronic Theses and Dissertations
Nuclei are termed unreceptive if they are not amenable to solid-state NMR (SSNMR) experimentation at standard magnetic field strengths due to (i) low natural abundances or dilution; (ii) low gyromagnetic ratios; (iii) inefficient longitudinal relaxation; (iv) large quadrupole moments; or (v) combinations of these factors. This thesis focuses on applying a variety of SSNMR methods to study unreceptive nuclei in a variety of systems. The first portion of this thesis focuses upon ultra-wideline (UW) SSNMR of three main group nuclei: 209Bi, 137Ba and 115In. 209Bi and 137Ba SSNMR were applied to a series of systems with important structural motifs, while …
Hydrogen Storage In Metal Fragments Grafted Silicas And Chromium Hydrazide Gels, Ahmad Hamaed
Hydrogen Storage In Metal Fragments Grafted Silicas And Chromium Hydrazide Gels, Ahmad Hamaed
Electronic Theses and Dissertations
Hexagonally-packed mesoporous silicas (HMS) grafted with low-valent titanium, vanadium, and chromium organometallic fragments possessing oxidation states between (II) and (IV) were synthesized, tested for their hydrogen storage capacities, and characterized by XRD, nitrogen adsorption, XPS, and EA. The effects of the variation in the surface area, pore size, transition metal type, and metal oxidation state, the organometallic loading levels, as well as the ligand environment on the H2 adsorption capacity and the binding enthalpies of these systems were investigated. This study demonstrated that titanium is more effective at hydrogen binding than vanadium and chromium. HMS silica grafted with benzyl titanium …
Characterization Of Inorganic Catalysts And Materials By Solid-State Nmr, Aaron Rossini
Characterization Of Inorganic Catalysts And Materials By Solid-State Nmr, Aaron Rossini
Electronic Theses and Dissertations
This thesis demonstrates the application of solid-state nuclear magnetic resonance (SSNMR) spectroscopy to probe the structure of a variety of inorganic complexes and materials, many of which find applications in catalysis. Particular focus is given to SSNMR spectroscopy of "exotic" and unreceptive NMR nuclei. Complimentary characterization techniques such as quantum chemical calculations and X-ray diffraction experiments are also employed. The initial focus of the thesis is on the characterization of crystalline molecular metallocenes by 35Cl, 47/49Ti and 91Zr SSNMR spectroscopy. All of these nuclei are considered to be unreceptive for NMR experiments due to a combination of low natural abundance, …
The Influence Of Temperature And Chemical Hydrophobicity On Steady And Non-Steady State Polychlorinated Biphenyl Bioaccumulation In Temperate Fish, Michael Burtnyk
The Influence Of Temperature And Chemical Hydrophobicity On Steady And Non-Steady State Polychlorinated Biphenyl Bioaccumulation In Temperate Fish, Michael Burtnyk
Electronic Theses and Dissertations
This thesis investigated the effects of temperature and chemical hydrophobicity on steady and non-steady state bioaccumulation of polychlorinated biphenyls over the lifetime of temperate freshwater fish. In Chapter 2, the elimination of congeners of logKow < 5.7 by yellow perch (Perca flavescens) was regulated by temperature-dependant metabolic rates. Congeners of logKow > 5.7 however, were not significantly eliminated at any temperature commonly encountered by temperate fishes. It was concluded that the bioaccumulation of congeners of logKow > 5.7 is regulated by energetically driven consumption rates. This conclusion was confirmed in Chapter 3, where it was determined that the majority of congeners of logKow > 6.8 did not achieve steady state within the lifetime of bluegill (Lepomis macrochirus) or cisco …
New Liquid Crystalline [2]Rotaxanes, Natalie Suhan
New Liquid Crystalline [2]Rotaxanes, Natalie Suhan
Electronic Theses and Dissertations
This thesis presents design, synthesis and characterization of a range of new liquid crystalline interlocked molecules and to study structure-property relationships between rotaxane design and mesomorphism. Chapter 1 introduces concepts of supramolecular chemistry and liquid crystals and cooperative effect between [2]rotaxane and liquid crystals towards functional molecular machines. In Chapter 2, a systematic approach to introduce liquid crystallinity into the 1,2-bis(pyridinium)ethane/DB24C8 motif is described. The chapter begins with synthesis and purification of dumbbells (without macrocycle) and [2]rotaxanes (with macrocycle) substituted with purely aliphatic extended 3,5-disubstituted stoppers with increasing alkyl chain length. Chapter continues with phase characterization and structure-property relationships between …
Synthesis And Reactivity Of Early Transition Metal "Frustrated Lewis Pairs", Ojisamola Adeseeke Labeodan
Synthesis And Reactivity Of Early Transition Metal "Frustrated Lewis Pairs", Ojisamola Adeseeke Labeodan
Electronic Theses and Dissertations
Our research group recently introduced the new concept of "Frustrated Lewis Pairs" (FLP) wherein sterically demanding Lewis acids and bases do not interact in the expected donor-acceptor fashion, but rather exhibit unique reactivity. To date this concept of FLPs has been limited to main group systems. In this thesis we demonstrate that Lewis acidic early metal cations can activate small molecules in the presence of sterically demanding donors to exhibit unique reactivity. The cationic Lewis acids [Cp2Zr(O't'Bu)] +, [Cp2Zr(OPh)]+, [Cp2Zr(OMes)] + and [Cp2Zr(ODipp)]+ are generated by the reaction between the neutral precursor compound and methyl abstracting reagents [Ph3C][B(C6F5)4] and B(C …
Nonlinear Dynamics In Bromate-Based Chemical Oscillators, Nan Li
Nonlinear Dynamics In Bromate-Based Chemical Oscillators, Nan Li
Electronic Theses and Dissertations
During the course of this work, I discovered that the presence of 1,4-benzoquinone not only could induce various complex behaviors but also significantly enhance the photosensitivity of the BZ system. Mechanistic study suggests that the kinetic influence of 1,4-benzoquinone mainly arises from its interaction with ferriin to form a complex. In the photo-mediated 1,4-benzoquinone-bromate oscillator, dramatic changes in the reaction behavior were achieved upon the initial presence of hydroquinone. Measurements with UV/Vis spectroscopy and MS spectrometry suggest that the formation of hydroquinone-benzoquinone dimer plays a significant kinetic role in the studied system. Further mechanistic investigations on the photo-illuminated Q-bromate reaction …
Studying The Anti-Cancer Potential Of The Natural Compound Pancratistatin., Amanda Mclachlan-Burgess
Studying The Anti-Cancer Potential Of The Natural Compound Pancratistatin., Amanda Mclachlan-Burgess
Electronic Theses and Dissertations
One of the current challenges in the fight against cancer is to find anti-cancer treatments that specifically target cancerous cells, while leaving normal cells unharmed. Apoptosis, or programmed cell death, is a non-traumatic, physiological process by which cells that are no longer needed or are potentially harmful can be removed from the system. Recently, anti-cancer research has focused on targeting the components of biochemical pathways that can induce apoptosis specifically in cancerous cells. The search for cancer-specific drugs has led some researchers to investigate the potential anti-cancer activity of natural compounds. Pancratistatin (PST) is a natural compound that was isolated …
Nickel(0) Catalyzed Carbon-Hydrogen Bond Activation: A Mechanistic Study Of The Formation Of A Nickel(I)-Nickel(I) Complex., Alana Lauren Keen
Nickel(0) Catalyzed Carbon-Hydrogen Bond Activation: A Mechanistic Study Of The Formation Of A Nickel(I)-Nickel(I) Complex., Alana Lauren Keen
Electronic Theses and Dissertations
The first part of this thesis deals with a mechanistic investigation into the conversion of the known benzyne complex, Ni(eta2-C 6H2F2)(PEt3)2, to the novel dinuclear Ni(I)-Ni(I) complex, (PEt3)4Ni2(eta 2-C6H2-4,5-F2)2. The coupling of two molecules of Ni(eta2-C6H2F 2)(PEt3)2 does not result in the formation of (PEt3)4Ni2(eta2-C6 H2-4,5-F2)2. There is a rearrangement in the disposition of the hydrogen atoms from para disposed in Ni(eta 2-C6H2F2)(PEt3)2 to ortho disposed in (PEt3)4Ni2(eta 2-C6H2-4,5-F2)2, which was found to be the result of C-H bond activation catalyzed by Ni(0). Proposed mechanisms involving the isolated reaction intermediates Ni2(mu-eta 2:eta2-C6H2F2)(PEt 3)2 and (PEt3)2(PMe3) 2Ni2(eta2-C6H2-3,4-F 2)2 are given and …
Nonlinear Instabilities In Photochemical Oxidations Of 1,4-Cyclohexanedione And Its Derivatives., Bei Zhao
Nonlinear Instabilities In Photochemical Oxidations Of 1,4-Cyclohexanedione And Its Derivatives., Bei Zhao
Electronic Theses and Dissertations
In the closed 1,4-cyclohexanedione(CHD) bromate oscillatory reaction, we discovered that stirring can induce transitions between simple and period-doubled oscillations. When illumination was employed to characterize the importance of micro fluctuations of concentrations, the threshold stirring rate for inducing a bifurcation was found to increase proportionally to the intensity of the applied light. Numerical simulations with an existing model illustrate that the experimental phenomena could be qualitatively reproduced by considering effects of mixing on diffusion-limited radical reactions, namely, the disproportion reaction of hydroquinone radicals. A novel light-mediated chemical oscillator, i.e. 1,4-benzoquione(Q-bromate oscillator, was uncovered and investigated systematically in a batch reactor. …
Syntheses And Reactivities Of Improved Univalent Indium Salts., Christopher G. Andrews
Syntheses And Reactivities Of Improved Univalent Indium Salts., Christopher G. Andrews
Electronic Theses and Dissertations
Reported herein are the syntheses and characterizations for a number of new families of compounds containing the main group metal indium in its relatively uncommon univalent oxidation state. Starting from the known half-sandwich compound Cp*In, (Cp* = pentamethylcyclopentadienyl) it is possible to effect a clean and facile cleavage of the organic ring from the metal with the addition of a non-oxidizing Bronstead acid. Once removal of the hydrocarbon by-product is accomplished, the metal is left in a binary salt with the conjugate base of the Bronstead acid used. This protonolysis approach is a versatile method allowing for easy selection of …
Anion Interactions Of [2]Pseudorotaxanes And [2]Rotaxanes., Iavor S. Mihalkov
Anion Interactions Of [2]Pseudorotaxanes And [2]Rotaxanes., Iavor S. Mihalkov
Electronic Theses and Dissertations
This thesis describes studies on the interactions of anions with [2]pseudorotaxanes and [2]rotaxanes comprised of 24-membered crown ether wheels and bis(pyridinium)ethane axles which incorporate an amide anion receptor. Eight nicotinamide-based threads containing a bis(pyridinium)ethane recognition motif were synthesized. Their ability to form [2]pseudorotaxane complexes with 24-membered crown ethers was determined by 1H NMR spectroscopy. The effect of anion binding on the stability of the [2]pseudorotaxanes was investigated using 1H NMR titrations. Nine [2]rotaxanes were synthesized from the combination of three threads and three crown ethers---dibenzo-, dinaphtho-, and naphtho-24-crown-8. The selectivity of the amide receptor towards small inorganic anions---halides and dihydrogenphosphate---were …
Vanadium Phosphinimide Complexes For Ethylene Polymerization And The Chemistry Of Phosphinimines And Phosphine Oxides With Borane Reagents, Sarah Bess Hawkeswood
Vanadium Phosphinimide Complexes For Ethylene Polymerization And The Chemistry Of Phosphinimines And Phosphine Oxides With Borane Reagents, Sarah Bess Hawkeswood
Electronic Theses and Dissertations
A reproducible and high yielding synthesis of the vanadium imide phosphinimide complexes of the general formula V(NAr)(NPR3)Cl2 (Ar = Ph, C6H3-2,6-i-Pr2; R = i-Pr, t-Bu, Ph) has been developed. These complexes upon activation by methylaluminoxane demonstrated low to moderate ethylene polymerization activities comparable to published vanadium imide complexes. The dichloride derivatives react readily with a variety of alkali metal salts and Grignard reagents to produce vanadium imide phosphinimide thiolate, alkyl, aryl, amide and alkoxide complexes. In the presence of Zn, reduction of V(NPh)(NPt-Bu3)Cl2 occurred to afford what is proposed to be a vanadium(IV) imide bridged dimeric species (V(mu-NPh)(NPt-Bu3)Cl)2. The reaction …
Sterically Bulky Nitrogen Based Ligands: New Chelate Complexes And Applications In Dehydrocoupling Catalysis., Jason Douglas Masuda
Sterically Bulky Nitrogen Based Ligands: New Chelate Complexes And Applications In Dehydrocoupling Catalysis., Jason Douglas Masuda
Electronic Theses and Dissertations
Routes to the sterically bulky chelating N,N'-based ligand systems (C 6H3i-Pr2)NC(Me)CH2PPh 2(NC6H3i-Pr2) and i-Pr2C6H3N(C(Me)NC 6H3i-Pr2)2 have been developed and their chemistries with Group 13 metals, specifically aluminum and gallium have been investigated. Highlights from this work include the isolation of neutral ligand-AIR2 species (R = Me, H) which in turn form cationic species when reacted with B(C6F5) 3 or [Ph3C][B(C6F5)4]. In addition, the N-imidoyl amidine ligand i-Pr2C 6H3N(C(Me)NC6H3i-Pr 2)2 reacts with three equivalents of AlMe3 to give the species [(i-Pr2C6H 3N(C(Me)NC6H3i-Pr2) 2)AlMe2][Al2Me7], which upon heating loses CH4 to give the neutral species (i-Pr 2C6H3N(C(=CH2)NC6H 3i-Pr2)(C(Me)NC6H3 i-Pr2)AlMe2. Kinetic studies have provided …
The Localization Of Protein Disulfide Isomerase And Further Evidence Towards Its Role As A Neuroprotective Protein In Sh-Sy5y Cells., Dana Seslija
Electronic Theses and Dissertations
Protein disulfide isomerase (PDI) is a multifunctional protein most well characterized for its ability to form and exchange disulfide bonds (Darby et al., 1996). The localization of PDI in differentiated human neuroblastoma SH-SY5Y cells was probed by the development of a recombinant fusion protein between green fluorescent protein GFP and PDI. SH-SY5Y cells expressing the recombinant reporter protein were also exposed to oxidative and ischemic stress, and examined for characteristics of apoptosis. These cells demonstrated that PDI provides a significant decrease in apoptotic traits as compared to the control cells. It was observed that there was reduced nuclear condensation, and …
Formation Of Cycloheptyne-Dicobalt Hexacarbonyl Complexes Via Nicholas Allylation Reactions And Ring Closing Metathesis: Intramolecular 2+2+2 And Pauson-Khand Reactions On Cycloheptyne Complexes., Ahmed Bashir Mohamed
Formation Of Cycloheptyne-Dicobalt Hexacarbonyl Complexes Via Nicholas Allylation Reactions And Ring Closing Metathesis: Intramolecular 2+2+2 And Pauson-Khand Reactions On Cycloheptyne Complexes., Ahmed Bashir Mohamed
Electronic Theses and Dissertations
One of the objectives of this thesis was to reduce the formation of vinyl silane side 140a,b,c & 145 products formed in the 4+3 cycloaddition reactions. By employing allyltrimetal nucleophile 149, virtually eliminated or reduced to trace amounts these vinyl silane side products observed earlier. DIBAL reduction and in situ acetylation, followed by exposuere to BF3 afforded cycloheptenyne dicobalt complex 156a,b & 163a, bearing a allyl trimethyl silane functional group and a silyl group at beta-position. The second and major objective of my thesis was to prepare tethered alkenes or alkynes of cycloheptyne dicobalt complexes. Cyloheptyne dicobalt complexes of 187, …
Identification Of Human Yvh1 Substrates And Binding Partners Using Biological Mass Spectrometry., Zareen Butt
Identification Of Human Yvh1 Substrates And Binding Partners Using Biological Mass Spectrometry., Zareen Butt
Electronic Theses and Dissertations
Dual specificity phosphatases belong to the protein tyrosine phosphatase family of enzymes. These members have the ability to dephosphorylate both phosphotyrosine and phosphoserine/-phosphothreonine residues on the substrate proteins and have been found to be the regulators of critical cellular functions such as cell growth and cell cycle progression. The first dual specificity phosphatase was identified from vaccina virus. Later studies found homologues of VH1 in other organisms including yeast and humans. The human homologue, hYVH1, is a 36kDa enzyme containing a novel zinc finger domain. This research project was carried out as a first step towards the physiological characterization of …
Rnai-Related Genes In Toxoplasma Gondii., Ahmad Al Riyahi
Rnai-Related Genes In Toxoplasma Gondii., Ahmad Al Riyahi
Electronic Theses and Dissertations
RNA interference (RNAi) is an evolutionarily conserved mechanism through which double-stranded RNA (dsRNA) triggers degradation of homologous transcripts. Argonaute proteins and small interfering RNAs (siRNAs) are the known signature components of the RNAi effector complex, named RNA-induced silencing complex (RISC). Our group previously reported that dsRNA-induced specific gene silencing is functional in Toxoplasma gondii, an intracellular parasite of humans and other mammals. In the present study, we describe the characterization of the first Argonaute protein (TgAgo) in T. gondii. The cDNA clone has an open reading frame (ORF) of 1575 bp which encodes a putative 524-amino-acid protein with a calculated …
Self-Assembled Platinum(Ii) Complexes For Anion Recognition., Chantelle R. Bondy
Self-Assembled Platinum(Ii) Complexes For Anion Recognition., Chantelle R. Bondy
Electronic Theses and Dissertations
The focus of this thesis is the development of novel anion receptors possessing conformational flexibility through the use of a simple inorganic framework. The complex cation, [PtL4]2+, can adopt four conformations inspired by calix[4]arene-based receptors: 'cone', 'partial cone', '1,2-alternate' or '1,3-alternate'. The first part of the thesis involves the synthesis, characterization and examination of the binding properties of three generations of anion receptors using 1H NMR spectroscopy and X-ray crystallography. The first generation receptor is [PtL4]2+ where L = 3-nbutylnicotinamide. Solution studies show moderate binding constants in polar solvents with preference for 1:2 binding of planar bidentate anions such as …
Chemical, Biochemical, And Physiological Aspects Of Nitric Oxide, S-Nitrosothiols, And Protein Disulfide Isomerase., Paul Root
Electronic Theses and Dissertations
Nitric oxide (NO•), S-nitrosothiols (RSNO), and cell surface protein disulfide isomerase (csPDI) are involved in many cellular processes. In this work, we investigate the participation of NO• and RSNO with respect to csPDI physiology. Omapatrilat (Omap) is developed by Bristol-Meyers Squibb for the treatment of hypertension. The effect of Omap treatment on two aspects of endothelial cell NO• metabolism was examined. Incubation with Omap resulted in an increase in the relative efficiency of L-arginine uptake (Vmax/K m), a precursor for NO• synthesis. Upon nitrosating the free sulthydryl group on Omap, we demonstrated its ability to deliver NO• to the cytosol …
Complex Reaction Dynamics In Bromate-Based Chemical Oscillators., Yu Chen
Complex Reaction Dynamics In Bromate-Based Chemical Oscillators., Yu Chen
Electronic Theses and Dissertations
In this study new oscillations system have been constructed by introducing 1,4-cyclohexanedion (CHD) into the ferroin- or cerium-catalyzed classic BZ reaction as a second organic substrate further. Since 1,4-CHD alone is capable of forming a chemical oscillator with bromate in an acidic environment, the presence of 1,4-CHD actually implements new autocatalytic nonlinear feedbacks. As a result the mixed BZ reaction actually consists of two bromate oscillators that are coupled together through such reagents as bromine dioxide, metal catalysts (ferroin/ferriin or Ce3+/Ce4+) etc. This is unique difference from existing studies of the BZ reactions using mixed organic substrates. Various complex oscillatory …
Computational Investigations On S-Nitrosothiols., Cristina Baciu
Computational Investigations On S-Nitrosothiols., Cristina Baciu
Electronic Theses and Dissertations
Several computational investigations on the properties of S-nitrosothiols (RSNOs) and other interactions with the biochemically important Cu + ions are described. In Chapter 3, the ability of conventional electron correlation (MP2 and QCISD) and DFT (B3LYP and B3P86) methods to provide accurate and reliable structures and homolytic S--N BDEs, for a range of RSNOs is considered. With a suitable large basis set, i.e., 6-311+G(2df,p) or larger, the different methods generally give optimized structures in close agreement with each other; the B3LYP method consistently overestimates r(S--N). The trends observed are due in part to the fact that the RS--NO bond does …
Functional Elucidation Of Lactate Dehydrogenase In Toxoplasma Gondii By Double-Stranded Rna Gene Suppression Mediation., Fatme Al-Anouti
Functional Elucidation Of Lactate Dehydrogenase In Toxoplasma Gondii By Double-Stranded Rna Gene Suppression Mediation., Fatme Al-Anouti
Electronic Theses and Dissertations
Toxoplasma gondii is an intracellular parasite of humans and other mammals which can differentiate between an active and a dormant form. Our primary interest was to modulate gene expression in T. gondii in order to investigate a putative gene function. The capability of double-stranded RNA to down-regulate gene expression has been demonstrated in various organisms but has yet to be demonstrated in intracellular organisms such as T. gondii. Therefore, the effect of in vitro synthesized double-stranded RNA was first investigated for the down-regulation effect of the homologous gene in T. gondii. Three non-essential marker genes which encode the green fluorescent …
Some Aspects Of The Cell Biology Of Lipid S-Nitrosothiols., Jiyun Wang
Some Aspects Of The Cell Biology Of Lipid S-Nitrosothiols., Jiyun Wang
Electronic Theses and Dissertations
Nitric Oxide is an important messenger and mediator in biological systems. Due to its short half life, S-nitrosothiols (RSNOs) have been suggested to be one of the important biomolecules for the storage and transport of NO. RSNOs also exhibit NO-like bioactivities. In the present study, we focus on the study of some aspects of cell biology of lipid S-nitrosothiols. In the first part of the study, we focus on the comparison of the cellular uptake of native LDL and chemically modified (homocysteinylation and S-nitrosation) LDL by Normal Human Fibroblasts (NHFs). Here, S-nitroso homocysteinylated LDL (LDL-SNO) was synthesized through the reaction …
Dendrimeric And Polymeric Rotaxanes Incorporating The Loeb Recognition Motif., David A, Tramontozzi
Dendrimeric And Polymeric Rotaxanes Incorporating The Loeb Recognition Motif., David A, Tramontozzi
Electronic Theses and Dissertations
Traditionally, dendrimeric and polymeric macromolecules have been pieced together using the strength of covalent and metal coordinative bonds. The incorporation of non-covalent interactions within these polymers may prove interesting in the fundamental role that interlocked components play in entanglements, rheology, elasticity and mechanical properties of the polymers in which they will be incorporated. The focus of this thesis is to explore the incorporation of the 1,2-bis(pyridinium)ethane (Loeb) rotaxane motif into various polymeric and dendrimeric architectures and study how these new interpenetrated and interlocked components affect the properties of the resulting systems. A series of molecules possessing both recognition elements covalently …
On The Understanding Of Metallocene Structure And Dynamics Via Solid-State Nmr., Ivan Hung
On The Understanding Of Metallocene Structure And Dynamics Via Solid-State Nmr., Ivan Hung
Electronic Theses and Dissertations
This thesis focuses on the use of solid-state NMR spectroscopy to study the metal nuclei in various metallocenes and metallocenium cations, including, Cp*2Al+, Cp*2B+, Cp* 2BMe, Cp2Be, Cp*2Be, (C5Me4H) 2Be, CP2Mg, Cp2ZrCl2, Cp*2ZrCl 2, Cp2ZrBr2, (C5Me3H 2)2ZrBr2, (Me3Si-C5H 4)2ZrBr2, O(Me2SiC5H 4)2ZrBr2, (O(Me2Si) 2C5H3)2ZrBr2, (Me2 ClSi-C5H4)ZrCl3, and Cp2ZrMe 2. Since few studies of this nature have been reported, much of the initial material involves examining the correlation between anisotropic quadrupolar and chemical shielding interaction tensors with structural and/or dynamic features of the metallocenes. Detailed quantum mechanical calculations are also employed in order to strengthen our understanding of these correlations and the …
Mesoporous Tantalum Oxide Catalysts For Nitrogen Fixation., Chaoyang Yue
Mesoporous Tantalum Oxide Catalysts For Nitrogen Fixation., Chaoyang Yue
Electronic Theses and Dissertations
A variety of mesoporous tantalum oxide supported catalytic systems were synthesized and investigated for their activities in nitrogen activation, including the Schrauzer-type photocatalytic process and the Haber-Bosch type thermocatalytic process. Mesoporous Ta oxide possesses a high thermal stability, high surface area, tunable wall composition and, most interestingly, variable oxidation states of the transitional metal sites. For this reason it represents a unique support for heterogeneous catalysis. Modification of the surface properties by doping active metal agents and various thermal treatments can further improve the activity. Results obtained in this work showed that for the photocatalytic process pure Ta oxide, with …
Lewis Acid-Base Interactions In The Synthesis Of Titanium Phosphinimide Cations., Lourdes Isabel Cabrera Lara
Lewis Acid-Base Interactions In The Synthesis Of Titanium Phosphinimide Cations., Lourdes Isabel Cabrera Lara
Electronic Theses and Dissertations
The active species Cp(NPtBu3)TiMe(mu-MeB(C 6F5)4) and [Cp(NPtBu3)TiMe] [B(C6F5)4], generated by the reaction of Cp(NPtBu3)TiMe2 with the activators B(C 6F5)3 and [C(C6H5) 3][B(C6F5)4], are thought to be the active species in olefin polymerization processes. Both species have been stabilized by the coordination of Lewis bases, pyridines (Py, 4-EtPy, 4- tBuPy, and 4-DMAP) and tertiary phosphines (PMe3, PnBu 3, P(C6H5)3, P(p-CH 3C6H4)3). The use of such Lewis bases allowed for the isolation and characterization of ion pair complexes of the general formula [Cp(NPtBu3)TiMe·LB] [RB(C 6F5)3] (LB = Lewis base; R = Me, C6F 5). These reactions show a dependency on the steric …
Phosphonium Stoppered [2]Rotaxanes And Molecular Shuttles., Norma Georges
Phosphonium Stoppered [2]Rotaxanes And Molecular Shuttles., Norma Georges
Electronic Theses and Dissertations
This thesis deals with the synthesis of [2]rotaxanes with single and double sites of recognition, containing pyridinium ethane units in their linear components. In the first part, one pyridinium ethane axle with a triethylphosphonium group on one end was synthesized and the possibility of its complexation with 24C8 derivatives was investigated. Although [2]pseudorotaxane formation was limited due to the bulk of the PR4+ stopper, [2]rotaxanes were formed utilising 24-crown-8 ether, benzo-24-crown-8 ether and naphtho-24-crown-8 ether. The crystal structure of the [2]rotaxane containing 24C8 was determined. The dynamic "flip-switch" activity of the asymmetric crown ethers was analysed by variable temperature NMR …