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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

The reaction of nitrosamines with carboxylic anhydrides ; 1-substituted aziridine nitrosation : structure/reaction path variation /

Zhang, Jingen, January 1996 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. I. precedes first title and II. precedes second title on title page. Vita. Includes bibliographical references. Also available on the Internet.
42

The reaction of nitrosamines with carboxylic anhydrides ; 1-substituted aziridine nitrosation

Zhang, Jingen, January 1996 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. I. precedes first title and II. precedes second title on title page. Vita. Includes bibliographical references. Also available on the Internet.
43

Electrical conduction in carbon-ion implanted diamond and other materials at low temperatures.

Tshepe, Tshakane Frans January 1992 (has links)
A research report submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science / The role of intersite electron correlation effects and the possible occurrence of the metal-insulator transition in carbon-ion implanted type IIa diamond samples have been studied at very low temperatures, using four- and two-point probe contact electrical conductivity measuring techniques. The measurements were extended to ruthenium oxide thin films in the presence and absence of a constant magnetic field of B = 4.0 T down to 100 mK, using a 3He-4He dilution refrigerator. The effect of the Coulomb gap in the variable range hopping regime has been well studied by other workers. The results tend to follow the Efros-Shklovskii behaviour with a trend towards the Mott T- 114 law for diamond samples far removed from the metal insulator transition, on the insulating side at low temperatures. / Andrew Chakane 2019
44

High resolution spectroscopy of sulfur trioxide and carbon suboxide

Masiello, Tony 01 May 2003 (has links)
Graduation date: 2003
45

A computational study of layered and superhard carbon-nitrogen material

Manyali, George Simiyu 04 February 2015 (has links)
A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. August 2014. / The process of the computational discovery of materials for future technologies is a combination of numerical techniques and general scientific intuition to select elements and combine in order to form novel types of materials. Modern ab initio methods based on density functional theory are capable of predicting with a high level of accuracy the most stable ground state atomic configurations of any given material. Once the ground state configurations are established, the electronic, optical and mechanical properties of the novel bulk nitrides may be determined. Electronic properties of C3N4, CN2, SiN2, GeN2, C2N2(NH), Si2N2(NH), Ge2N2(NH) and Sn2N2(NH) are analysed by computing the Kohn-Sham band structures. The optical properties are investigated by calculating the real and the imaginary parts of the frequency-dependent dielectric constant. The mechanical properties are determined by calculating elastic constants, Young’s modulus, Poisson’s ratio, Vickers hardness, shear and bulk moduli.
46

A study of the effects of nanoparticle modification on the thermal, mechanical and hygrothermal performance of carbon/vinyl ester compounds

Unknown Date (has links)
Enhancement of mechanical, thermal and hygrothermal properties of carbon fiber/vinyl ester (CFVE) composites through nanoparticle reinforcement has been investigated. CFVE composites are becoming more and more attractive for marine applications due to two reasons : high specific strength and modulus of carbon fiber and low vulnerability of vinyl ester resin to sea water. However, the problem with this composite system is that the fiber matrix (F/M) interface is inherently weak. This leads to poor mechanical properties and fast ingress of water at the interface further deteriorating the properties. This investigation attempts to address these deficiencies by inclusion of nanoparticles in CFVE composites. Three routes of nanoparticle reinforcement have been considered : nanoparticle coating of the carbon fiber, dispersion of nanoparticles in the vinyl ester matrix, and nanoparticle modification of both the fiber and the matrix. Flexural, short beam shear and tensile testing was conducted after exposure to dry and wet environments. Differential scanning calorimetry and dynamic mechanical analysis were conducted as well. Mechanical and thermal tests show that single inclusion of nanoparticles on the fiber or in the matrix increases carbon/vinyl ester composite properties by 11-35%. However, when both fiber and matrix were modified with nanoparticles, there was a loss of properties. / by Felicia M. Powell. / Thesis (Ph.D.)--Florida Atlantic University, 2012. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2012. Mode of access: World Wide Web.
47

The effects of nitric acid and silane surface treatments on carbon fibers and carbon/vinyl ester composites before and after seawater exposure

Unknown Date (has links)
This research focuses on carbon fiber treatment by nitric acid and 3- (trimethoxysilyl)propyl methacrylate silane, and how this affects carbon/vinyl ester composites. These composites offer great benefits, but it is difficult to bond the fiber and matrix together, and without a strong interfacial bond, composites fall short of their potential. Silanes work well with glass fiber, but do not bond directly to carbon fiber because its surface is not reactive to liquid silanes. Oxidizing surface treatments are often prescribed for improved wetting and bonding to carbon, but good results are not always achieved. Furthermore, there is the unanswered question of environmental durability. This research aimed to form a better understanding of oxidizing carbon fiber treatments, determine if silanes can be bonded to oxidized surfaces, and how these treatments affect composite strength and durability before and after seawater exposure. Nitric acid treatments on carbon fibers were found to improve their tensile strength to a constant level by smoothing surface defects and chemically modifying their surfaces by increasing carbonyl and carboxylic acid concentrations. Increasing these surface group concentrations raises fiber polar energy and causes them to cohere. This impedes wetting, resulting in poor quality, high void content composites, even though there appeared to be improved adhesion between the fibers and matrix. Silane was found to bond to the oxidized carbon fiber surfaces, as evidenced by changes in both fiber and composite properties. The fibers exhibited low polarity and cohesion, while the composites displayed excellent resin wetting, low void content, and low seawater weight gain and swelling. On the contrary, the oxidized fibers that were not treated with silane exhibited high polarity and fiber cohesion. / Their composites displayed poor wetting, high void content, high seawater weight gain, and low swelling. Both fiber treatment types resulted in great improvements in dry transverse tensile strength over the untreated fibers, but the oxidized fiber composites lost strength as the acid treatment time was extended, due to poor wetting. The acid/silane treated composites lost some transverse tensile strength after seawater exposure, but the nitric acid oxidized fiber composites appeared to be more seawater durable. / by Tye A. Langston. / Thesis (Ph.D.)--Florida Atlantic University, 2008. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2008. Mode of access: World Wide Web.
48

Base-promoted benzylic carbon-hydrogen bond activation and benzlic carbon-carbon bond activation with rhodium (III) porphyrin: scope and mechanism. / CUHK electronic theses & dissertations collection

January 2011 (has links)
Choi, Kwong Shing. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
49

Selective carbon(carbonyl)-carbon(α) bond activation of ketones by group 9 metalloporphyrins. / Selective carbon(carbonyl)-carbon(alpha) bond activation of ketones by group 9 metalloporphyrins / Selective carbon(CO)-carbon(α) bond activation of ketones by group 9 metalloporphyrins / CUHK electronic theses & dissertations collection

January 2012 (has links)
本文主要探討在有水的條件下,分別以銠卟啉和鈷卟啉絡合物與無張酮反應發生選擇羰基碳及α碳(C(CO)-C(α))鍵活化(下稱碳碳鍵活化)的反應活性和反應機。 / 在200°C,無張芳香和脂肪酮與5, 10, 15, 20-(四甲苯) 銠卟啉絡合物(RhIII(ttp)X,X = Cl 和Me)進反應,生成相對應的碳碳鍵活化產物-銠卟啉酰基絡合物,產最高可達97%。與甲基和乙基酮衍生物相比,丙基酮衍生物有較高的活性,而且丙基酮衍生物的碳碳鍵活化反應甚至能在50°C 的低溫條件下進。 / 根據化學計學,環酮的碳碳鍵開環反應顯示RhIII(ttp)OH 是斷開C(CO)-C(α)鍵的中間體。 / 進一步的反應機研究表明, RhIII(ttp)OH 的羥基是從水中得。RhIII(ttp)X首先進α碳氫鍵活化生成動學產物。經過水解,α碳氫鍵活化產物可以重新形成RhIII(ttp)OH。然後,RhIII(ttp)OH 繼續進碳碳鍵活。 / 另外,經濟的5, 10, 15, 20-(四甲苯) 鈷卟啉絡合物與丙基酮衍生物反應,在室溫下可選擇性進碳碳鍵活化並得到鈷卟啉酰基化合物,產最高達82%。根據化學計學,CoIII(ttp)OH 被認為是碳碳鍵活化的中間體。CoIII(ttp)OH很有可能是通過鈷卟啉與水的歧化反應生成的。 / This thesis focuses on the reactivities and mechanistic studies of the rhodium and cobalt porphyrins (M(por)X) assisted selective carbon(CO)-carbon(α) bond activation (CCA) of unstrained ketones with water. / Unstrained aromatic and aliphatic ketones reacted with 5,10,15,20-tetratolylporphyrinato rhodium(III) complexes, Rh[superscript III](ttp)X (X = Cl and Me), at 200°C to give the corresponding rhodium porphyrin acyls as the CCA products up to 97% yield. Isopropyl ketones exhibit much higher reactivities over methyl and ethyl ketones and the CCA can even occur at a low temperature of 50 °C. / The ring openmg CCA of cyclic ketones suggests the carbon(CO)-carbon(α)bond is cleaved by Rh(ttp )OH according to the reaction stoichiometry. / Further mechanistic investigations suggest that water is the source of hydroxyl group to form Rh[superscript III](ttp)OH. Rh[superscript III](ttp)X first undergoes α-carbon-hydrogen bond activation (α-CHA) to give a kinetic product. Hydrolysis of the α-CHA complex affords Rh[superscript III](ttp)OH for subsequent CCA process. / Alternatively, the economically attractive 5,1 0,15,20-tetratolylporphyrinato cobalt(II) complexes, Co[superscript II](ttp), reacted chemoselectively with isopropyl ketones at the carbon(CO)-carbon(α) bond under room temperature to give high yields of cobalt porphyrin acyls up to 82% yields. Co[superscript III](ttp)OH is identified to be the CCA intermediate as suggested by the reaction stoichiometry. Generation of Co[superscript III](ttp )OH from Co[superscript II](ttp) via the disproportionation with water is proposed. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Fung, Hong Sang. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Abstract --- p.i / Acknowledgements --- p.iv / Table of Contents --- p.v / Abbreviations --- p.ix / Structural Abbreviations for Porphyrins --- p.x / Chapter Chapter 1 --- General Introduction --- p.1 / Chapter 1.1 --- General Introduction to Carbon-Carbon Bond Cleavage --- p.1 / Chapter 1.1.1 --- Organic Examples of Carbon-Carbon Bond Cleavage --- p.1 / Chapter 1.1.2 --- Carbon-Carbon Bond Activation with Transition Metal 2Complexes --- p.2 / Chapter 1.1.2.1 --- Ring Strain Relief --- p.2 / Chapter 1.1.2.2 --- Chelation Assistance --- p.3 / Chapter 1.1.2.3 --- Aromatization --- p.3 / Chapter 1.1.2.4 --- Carbonyl Functionality --- p.4 / Chapter 1.1.2.5 --- β-Alkyl Elimination --- p.4 / Chapter 1.1.2.6 --- Formal Alkane Metathesis --- p.5 / Chapter 1.2 --- Carbon-Carbon Bond Cleavage of Ketones --- p.6 / Chapter 1.2.1 --- Properties of Ketones --- p.6 / Chapter 1.2.2 --- Organic Examples of Carbon-Carbon Bond Cleavage of Ketones --- p.7 / Chapter 1.2.2.1 --- Haloform Reaction --- p.8 / Chapter 1.2.2.2 --- Haller-Bauer Reaction --- p.8 / Chapter 1.2.2.3 --- Baeyer-Villiger & Dakin Oxidation --- p.9 / Chapter 1.2.2.4 --- Beckmann & Schmidt Rearrangement --- p.10 / Chapter 1.2.2.5 --- Favorskii Rearrangement --- p.11 / Chapter 1.2.2.6 --- Norrish Type I Reaction --- p.12 / Chapter 1.2.2.7 --- Hydrolysis with Water --- p.12 / Chapter 1.2.3 --- Carbon(CO)-Carbon(α) Bond Activation of Ketones with Transition Metal Complexes --- p.13 / Chapter 1.2.3.1 --- Stoichiometric C(CO)-C(α) Bond Activation of Ketones --- p.18 / Chapter 1.2.3.1.1 --- Metal Insertion into Strained Ring --- p.18 / Chapter 1.2.3.1.2 --- Decarbonylation --- p.19 / Chapter 1.2.3.1.3 --- Chelation Assisted CCA of Unstrained Ketones --- p.19 / Chapter 1.2.3.1.4 --- Reaction with Benzyne Complex --- p.20 / Chapter 1.2.3.1.5 --- Reaction with Metal Hydroxide --- p.21 / Chapter 1.2.3.2 --- Catalytic C(CO)-C(α) Bond Activation of Ketones --- p.22 / Chapter 1.2.3.2.1 --- Decarbonylation --- p.22 / Chapter 1.2.3.2.2 --- Insertion with Unsaturated Compounds --- p.23 / Chapter 1.2.3.2.3 --- Hydrogenolysis --- p.24 / Chapter 1.2.3.2.4 --- Ring Fusion --- p.25 / Chapter 1.3.3.2.5 --- [4+2+2] Annulation --- p.26 / Chapter 1.2.3.2.6 --- Alcoholysis and Aminolysis --- p.27 / Chapter 1.2.3.2.7 --- Hydroarylation --- p.28 / Chapter 1.2.3.2.8 --- Arylative Ring Expansion with Alkynes --- p.29 / Chapter 1.3 --- Water as An Oxidizing Agent --- p.29 / Chapter 1.3.1 --- Water-Gas Shift Reaction --- p.30 / Chapter 1.3.2 --- Hydration of C-C π-Bond --- p.31 / Chapter 1.3.3 --- Cleavage of C≡C Bond --- p.31 / Chapter 1.3.4 --- Oxidation of C-H Bond --- p.32 / Chapter 1.4 --- Transition Metal Hydroxide Chemistry --- p.33 / Chapter 1.4.1 --- Preparation of Group 9 Metal Hydroxides --- p.34 / Chapter 1.4.1.2 --- Ligand Substitution --- p.34 / Chapter 1.4.1.3 --- Oxidative Addition --- p.34 / Chapter 1.4.1.4 --- Hydrolysis --- p.35 / Chapter 1.4.2 --- Chemistry of Transition Metal Hydroxide --- p.35 / Chapter 1.5 --- Introduction to Porphyrins and Group 9 Metalloporphyrins --- p.37 / Chapter 1.5.1 --- Porphyrin Ligand --- p.37 / Chapter 1.5.2 --- Metalloporphyrins --- p.38 / Chapter 1.5.3 --- Chemistry of Group 9 Metalloporphyrins --- p.39 / Chapter 1.5.3.1 --- M[superscript I](por) Chemistry --- p.40 / Chapter 1.5.3.2 --- M[superscript II](por) Chemistry --- p.41 / Chapter 1.5.3.3 --- M[superscript III](por) Chemistry --- p.44 / Chapter 1.5.4 --- Equilibration of MI(por), MI (por) and MIII(por) --- p.46 / Chapter 1.5.5 --- Chemistry of Group 9 Metalloporphyrin Hydroxide --- p.47 / Chapter 1.5.5.1 --- Metalloether Formation --- p.47 / Chapter 1.5.5.2 --- Reductive Dimerization --- p.48 / Chapter 1.5.5.3 --- Oxidation --- p.49 / Chapter 1.5.5.4 --- Carbon-Hydrogen Bond Activation --- p.50 / Chapter 1.5.5.5 --- Carbon-Carbon Bond Activation --- p.51 / Chapter 1.6 --- Scope of Thesis --- p.52 / Chapter Chapter 2 --- Carbon(CO)-Carbon(α) Bond Activation of Ketones with Rhodium(lII) Porphyrin Complexes --- p.63 / Chapter 2.1 --- Introduction --- p.63 / Chapter 2.2 --- Objectives of the Work --- p.66 / Chapter 2.3 --- Preparation of Starting Materials --- p.66 / Chapter 2.3.1 --- Synthesis of Porphyrin --- p.66 / Chapter 2.3.2 --- Synthesis of Rhodium(III) Porphyrin Chloride --- p.67 / Chapter 2.3.3 --- Synthesis of Rhodium(III) Porphyrin Methyl --- p.67 / Chapter 2.3.4 --- Synthesis of Rh[superscript III](ttp)H --- p.68 / Chapter 2.3.5 --- Synthesis of Rh[superscript II]₂(ttp)₂ --- p.68 / Chapter 2.3.6 --- Synthesis of Rh[superscript I](ttp)-Na⁺ --- p.68 / Chapter 2.4 --- Optimization of Reaction Conditions with Acetophenone --- p.68 / Chapter 2.4.1 --- Reaction with Rh[superscript III](ttp )OTf, Rh[superscript III](ttp)Cl and Rh[superscript III](ttp)Me --- p.68 / Chapter 2.4.2 --- Temperature Effect --- p.70 / Chapter 2.4.3 --- Porphyrin Ligand Effect --- p.70 / Chapter 2.5 --- Substrate Scope of the CCAReaction --- p.71 / Chapter 2.5.1 --- CCA of Acetophenones --- p.71 / Chapter 2.5.2 --- CCA of Aromatic and Aliphatic Ketones --- p.72 / Chapter 2.6 --- Low Temperature CCA with Isopropyl Ketones --- p.76 / Chapter 2.7 --- Oxidation of the C(CO)-C(α) Bond --- p.77 / Chapter 2.8 --- Water as a Source of Oxidant --- p.80 / Chapter 2.9 --- Regioselectivity of CCA --- p.81 / Chapter 2.1 --- 0 X-ray Structure Determination --- p.83 / Chapter 2.11 --- Mechanistic Studies --- p.92 / Chapter 2.11.1 --- Proposed Mechanism --- p.92 / Chapter 2.11.2 --- Aldol Condensation Catalyzed by Rh(ttp)X (X = Me or Cl) --- p.93 / Chapter 2.11.3 --- Carbon-Hydrogen Bond Activation with Rh(ttp)X (X = Me or Cl) --- p.94 / Chapter 2.11.4 --- Hydrolysis of the α-CHA Product 100 --- p.100 / Chapter 2.11.5 --- Carbon(CO)-Carbon(α) Bond Oxidation with Rh(ttp)OH --- p.102 / Chapter 2.11.6 --- Dehydrogenation of Alcohol --- p.108 / Chapter 2.11.7 --- Thermodynamic Consideration --- p.109 / Chapter 2.12 --- Conclusion --- p.110 / Chapter Chapter 3 --- Carbon(CO)-Carbon(α) Bond Activation of Ketones with Cobalt(II)Porphyrin Complexes --- p.114 / Chapter 3.1 --- Introduction --- p.114 / Chapter 3.2 --- Objectives of the Work --- p.115 / Chapter 3.3 --- Preparation of Starting Materials --- p.115 / Chapter 3.3.1 --- Synthesis of H₂(tp-clPP) --- p.115 / Chapter 3.3.2 --- Synthesis of Co[superscript II] (por) --- p.116 / Chapter 3.4 --- Strategies of C(CO)-C(α) Bond Activation with Cobalt(II) Porphyrins --- p.116 / Chapter 3.5 --- Optimization of Reaction Conditions with Diisopropyl Ketone --- p.118 / Chapter 3.5.1 --- Solvent Effect --- p.118 / Chapter 3.5.2 --- Water Effect --- p.119 / Chapter 3.5.3 --- PPh3 Effect --- p.120 / Chapter 3.5.4 --- Porphyrin Ligand Effect --- p.121 / Chapter 3.5.5 --- Temperature Effect --- p.122 / Chapter 3.6 --- CCA of Isopropyl Ketones --- p.123 / Chapter 3.7 --- X-ray Structure Determination --- p.126 / Chapter 3.8 --- Mechanistic Studies --- p.131 / Chapter 3.8.1 --- Proposed Mechanism --- p.131 / Chapter 3.8.2 --- Disproportionation of Co[superscript II](ttp) with Water --- p.132 / Chapter 3.8.3 --- Dehydrogenation of Co[superscript III](ttp)H --- p.132 / Chapter 3.8.4 --- C(CO)-C(α) Bond Activation --- p.134 / Chapter 3.8.5 --- Dehydrogenation of the Alcohol --- p.134 / Chapter 3.8.6 --- Overall Enthalpy Change --- p.134 / Chapter 3.9 --- Stoichiometric Functionalization --- p.135 / Chapter 3.10 --- Conclusion --- p.138 / Chapter Chapter 4 --- Comparison on Carbon-Carbon Bond Activation by Cobalt, Rhodium and Iridium Porphyrin --- p.142 / Chapter 4.1 --- Introduction --- p.142 / Chapter 4.2 --- Reactivities of Metalloporphyrins --- p.143 / Chapter 4.3 --- Thermodynamic of CCA --- p.144 / Chapter 4.4 --- Rate of CCA --- p.147 / Chapter 4.5 --- Scope and Reactivities of Ketones --- p.147 / Chapter 4.6 --- Regioselectivities --- p.149 / Chapter 4.7 --- Chemoselectivity --- p.150 / Chapter 4.8 --- Conclusion --- p.152 / Chapter Chapter 5 --- Experimental Section --- p.153 / Appendices --- p.181
50

Silicon-Hydrogen (Si-H), Aryl-Fluorine (Aryl-F) and Carbon-Carbon (C-C) bond activations by Iridium Porphyrin complexes. / CUHK electronic theses & dissertations collection

January 2010 (has links)
*Please refer to dissertation for diagrams. / Part I describes the silicon-hydrogen bond activation (SiHA) of silanes with both electron-deficient iridium porphyrin carbonyl chloride (Ir(ttp)Cl(CO)) and electron-rich iridium porphyrin methyl (Ir(ttp)Me) to give iridium(III) porphyrin silyls (Ir(ttp)SiR3). Firstly, Ir(ttp)SiR3 were synthesized in moderate to good yields conveniently from the reactions of Ir(ttp)Cl(CO) and Ir(ttp)Me with silanes, via SiHA in solvent-free conditions and non-polar solvents at 200°C. Base facilitated the SiHA reaction even at lower temperature of 140°C. Specifically, K3PO4 accelerated the SiHA with Ir(ttp)Cl(CO), while KOAc promoted the SiHA by Ir(ttp)Me. Mechanistic experiments suggest that Ir(ttp)Cl(CO) initially forms iridium porphyin cation (Ir(ttp)+), which then reacts with silanes likely via heterolysis to give iridium porphyrin hydride (Ir(ttp)H). Ir(ttp)H further reacts with silanes to yield Ir(ttp)SiR3. On the other hand, Ir(ttp)Me and Ir(ttp)SiR3 undergo either oxidative addition (OA) or sigma-bond metathesis (SBM) to form the products. In the presence of base, a penta-coordinated silicon hydride species likely forms and reacts with Ir(ttp)Me to form iridium porphyrin anion (Ir(ttp) -) that can further react with silane to yield Ir(ttp)H after protonation. Ir(ttp)H finally reacts with excess silane to give Ir(ttp)SiR 3.* / Part II describes successful base promoted aromatic carbon-fluorine (C-F) and carbon-hydrogen (C-H) bond activation of fluorobenzenes in neat conditions to give the corresponding iridium(III) porphyrin aryls (Ir(ttp)Ar) at 200°C in up to 95% yield. Mechanistic studies suggested that Ir(ttp)SiEt3 is firstly converted to Ir(ttp)- in the presence of KOH. Ir(ttp)- cleaves the aromatic C-F bond via an S NAr process. As the reaction proceeds, a hydroxide anion can coordinate to the iridium center of Ir(ttp)Ar to form an iridium porphyrin trans aryl hydroxyl anion (trans-[ArIr(ttp)OH]-). In the presence of water, trans-[ArIr(ttp)OH]- can give Ir(ttp)OH and ArH. Ir(ttp)OH then undergoes aromatic C-H bond activation reaction to give Ir(ttp)Ar'. Furthermore, the aromatic C-F bond activation products were found as the kinetic products, and aromatic C-H bond activation products were the thermodynamic ones.* / Part III describes the successful C(C=O)-C(alpha) bond activation of acetophenones by high-valent iridium porphyrin complexes (Ir(ttp)X, X = Cl(CO), (BF4)(CO), Me) in solvent-free conditions at 200°C to give the corresponding iridium porphyrin benzoyls (Ir(ttp)COAr) in up to 92% yield. Mechanistic studies suggest that Ir(ttp)X reacts with acetophenones to give alpha-CHA product as the primary product, which can re-convert back to the active intermediate Ir(ttp)OH or Ir(ttp)H in the presence of water formed from the concurrent iridium-catalyzed aldol condensation of acetophenones. Then Ir(ttp)OH cleaves the aromatic C-H bonds to produce the aromatic CHA products, which are more thermally stable than the alpha-CHA product. Both Ir(ttp)H and Ir(ttp)OH were the possible intermediates to cleave the C(C=O)-C(alpha) bond to give thermodynamic products of Ir(ttp)COAr. On the other hand, only Ir(ttp)(BF 4)(CO) can react with the aliphatic ketones, likely due to the stronger Lewis acidity and the HBF4 generated in catalyzing the aldol condensation of aliphatic ketones to facilitate the formation of Ir(ttp)OH and Ir(ttp)H.* / The objectives of the research focus on the bond activation chemistry by iridium porphyrin complexes with three organic substrates, (1) hydrosilanes (HSiR3), (2) fluorobenzenes (C6HnF6-n , n = 0--6), and (3) aromatic or aliphatic ketones (RCOR, R = alkyl or aryl). / Li, Baozhu. / Adviser: Kin Shing Chan. / Source: Dissertation Abstracts International, Volume: 72-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese.

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