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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 …
Titanium Phosphinimide Complexes For Ethylene Polymerization Catalysis: Synthetic, Computational And Polymerization Testing Investigations., Chad Lee Beddie
Titanium Phosphinimide Complexes For Ethylene Polymerization Catalysis: Synthetic, Computational And Polymerization Testing Investigations., Chad Lee Beddie
Electronic Theses and Dissertations
The influences of the steric and electronic properties of phosphinimide ligands on the ethylene polymerization activity of cyclopentadienyl titanium phosphinimide complexes have been investigated. These efforts resulted in a new family of very high activity ethylene polymerization catalysts and have defined the principles required for future improvements in related catalyst systems. A reliable polymerization testing method that allows control of variables which affect polymerization activity has been established. For example, a series of experiments employing the Cp*TiMe2[NP(N(Et)(Ph)) 3]/B(C6F5)3 catalyst system resulted in polymerization activities ranging from 0 to 5500 g mmol-1 hr-1 atm-1, thus illustrating the sensitivity of the catalyst …
Discotic Liquid Crystalline Star-Shaped Hetero Heptamers For Organic Photovoltaic Devices., Anupama Jale
Discotic Liquid Crystalline Star-Shaped Hetero Heptamers For Organic Photovoltaic Devices., Anupama Jale
Electronic Theses and Dissertations
This thesis describes synthetic approaches to heteroheptamers of discotic liquid crystals, which should be ideal building blocks for organic photovoltaic devices. Hexaazatriphenylene-hexacarboxylic acid [HAT(CO2H) 6] and its derivatives were chosen as n-type semi-conducting central discotic monomer that has six p-type semi-conducting hexaalkoxytriphenylene discogens covalently attached to it. HAT derivatives were successfully synthesized and their conversions with alkyl alcohols and amines to hexaesters and hexa-amides are discussed. A complete conversion of all acid or ester groups with low molecular weight alcohols and amines was not achieved but transesterification of the hexa-methylester with alkyl alcohols catalyzed by titanium (IV) isopropoxide gave 80--90% …
Role Of Mitochondria In Neuronal Cell Death Induced By Oxidative Stress: Neuroprotection By Coenzyme Q(10)., Mallika Somayajulu
Role Of Mitochondria In Neuronal Cell Death Induced By Oxidative Stress: Neuroprotection By Coenzyme Q(10)., Mallika Somayajulu
Electronic Theses and Dissertations
In past research, oxidative stress has been implicated in aging and age related disorders. Cell death caused by oxidative stress has been shown to play an important role in neuro-degenerative diseases. We used differentiated Human Neuroblastoma (SH-SY5Y) and Teratocarcinoma (NT2N) cells as models to study the mechanism of cell death induced by oxidative stress. We observed that differentiated NT2N AND SH-SY5Y cells underwent apoptosis following oxidative stress induced by direct hydrogen peroxide treatment. Morphological, apoptotic features including nuclear condensation and membrane blebbing and biochemical changes including DNA fragmentation and caspase and proteasome activation were evident following oxidative stress. We further …
Annulation Reactions Toward Bicyclic And Tricyclic Cycloheptyne Dicobalt Complexes., Yu Ding
Annulation Reactions Toward Bicyclic And Tricyclic Cycloheptyne Dicobalt Complexes., Yu Ding
Electronic Theses and Dissertations
Cycloheptane containing molecules widely occur in nature; however, the methods for rapid synthesis of those type compounds are limited. This thesis focused on the annulation reactions toward fused ring systems bearing a cycloheptyne dicobalt complex. A series of benzocycloheptyne dicobalt complexes 58 have been synthesized from conjugated (Z) enyne acetate dicobalt complexes 59 by intramolecular Nicholas reactions. Fused [7,6,5] system 101 has also been obtained in a one-pot reaction via [4+3] cycloadditionlintramolecular trapping reaction. In addition, the progress in intramolecular [4+2] cycloaddition of complex 80 is discussed.
Synthesis Of Octa-Acids And -Amines Of Phthalocyanines And Tetraazaporphyrins., Hui Sheng Li
Synthesis Of Octa-Acids And -Amines Of Phthalocyanines And Tetraazaporphyrins., Hui Sheng Li
Electronic Theses and Dissertations
Several synthetic pathways towards octa-alkyl acid phthalocyanines and octa-alkyl amine phthalocyanines and their precursors have been developed. The preparation of three octa-acids with different aliphatic spacer chains has been completed successfully and the proposed structures Pc-C n-COOH (n = 3, 5, 10) agree with the obtained spectroscopic data (UV-VIS, IR, and MS). As an alternative route to octa-acid and -amine discotic liquid crystals we wanted to demonstrated that octa-alcohol precursors, such as previously synthesized octa-hydroxyalkylthiotetraazaporphyrins (TAPS-Cn-OH , n = 3, 6, 8, 11), can be converted to the acids or amines by esterification with cyclic anhydrides (maleic anhydride) or amino-protected …
Metal-Based [2] And [3]Rotaxanes., Gregory J. E. Davidson
Metal-Based [2] And [3]Rotaxanes., Gregory J. E. Davidson
Electronic Theses and Dissertations
The focus of this thesis is to synthesize, characterize and investigate the properties of [2]rotaxanes and [3]rotaxanes for the purposes of developing molecular level machines. In the first part of the thesis the coordination chemistry of the [2]rotaxane 1,2-bis(4,4'-dipyridinium)ethane/dibenzo-24-crown-8 is investigated. The production of zwitterionic and dizwitterionic [2]rotaxanes produced upon capping with an anionic metal complex is described. The complexes are studied in solution using UV/vis spectroscopy and characterized by X-ray crystallography. The same system, 1,2-bis(4,4'-dipyridinium)ethane/dibenzo-24-crown-8, is then used for the development of 1- and 2-dimensional infinite networks. The networks are characterized by X-ray crystallography and their stability is studied …
Regiochemical Studies For Nucleophilic Addition On Allylic Acetate Cycloheptyne Cobalt Complexes And The Progression Towards The Synthesis Of 7,5-Bicyclic Ring Systems Containing The Cobalt Complex., Joseph Dimartino
Electronic Theses and Dissertations
There are several naturally occurring compounds that have fused 7,5-bicyclic ring systems. This thesis will focus on approaches to synthesizing 7,5-bicyclic systems containing a dicobalt hexacarbonyl complex. In this context, the allylic acetate cycloheptenyne complex (66) was reacted with various carbon- and hetero-based nucleophiles to determine the regiochemistry of the substitution. The gamma to alpha ratio for carbon-based nucleophiles were approximately 4:1, while hetero-based nucleophiles were 100% gamma. Once the ratios were established, several of these product compounds, which contained an electrophilic site, were investigated for further reaction to form the additional ring (Scheme 28). Formation of a 7,5-bicyclic ketone …
Supramolecular Complexes Containing Pyridine N-Oxides., Dennis J. Hoffart
Supramolecular Complexes Containing Pyridine N-Oxides., Dennis J. Hoffart
Electronic Theses and Dissertations
In the first section, the coordination chemistry of a new, divergent, N,O ligand was investigated. Several metal complexes of 4,4 '-bipyridine N-monoxide, 2a, were characterised by X-ray crystallography, including CuI, Cu II, PdII, CdII, HgII, and EuIII. The observed non-covalent interactions and coordinative preferences of 2a were contrasted with those of 4,4' -bipyridine and 4,4'-bipyridine N,N '-dioxide. Each of the compounds has a unique molecular topology that can be applied to the generation of ordered, pre-designed solids. Examples of this methodology are given with respect to the CuI, Cu II, and HgII metal complexes. Chapter three is concerned with the …
Synthesis And Systematic Studies Of The Electronic And Magnetic Properties Of Alkali Fulleride Intercalates In Mesoporous Tantalum Oxide., Boris O. Skadtchenko
Synthesis And Systematic Studies Of The Electronic And Magnetic Properties Of Alkali Fulleride Intercalates In Mesoporous Tantalum Oxide., Boris O. Skadtchenko
Electronic Theses and Dissertations
Herein we report the synthesis and systematic study of a new family of alkali fulleride A3C60 (A = Na, Li, Rb) doped mesoporous tantalum oxide nanocomposites. This study allowed us to chart the dependency of conductivity and electromagnetic properties on the oxidation state of one-dimensional fullerides and elucidate the role of absolute carbon loading level in the pores of mesostructure. The role of alkali metal in the conducting properties of these composite materials and possible mechanisms of electron transfer upon reduction of fulleride is also discussed. Results presented in this work indicated that in case of Na and Rb fullerides …