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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.
11

Carbon-carbon bond activation of nitroxides and nitriles by rhodium(II) porphyrin. / CUHK electronic theses & dissertations collection

January 2006 (has links)
Mechanistic investigation has been carried out for the reaction between Rh(tmp) and the nitroxide, 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO). Mechanistically, Rh(tmp) at first coordinated with one molecule of TEMPO to produce a 1:1 adduct. Through this complex, parallel major carbon-carbon bond activation (CCA) and minor carbon-hydrogen bond activation (CHA) occurred. CCA was more favorable at higher reaction temperatures. The CHA product Rh(tmp)H further reacted with excess TEMPO to produce Rh(tmp) again for further CCA and CHA. The overall activation reaction was found to follow second order kinetics, rate = k [Rh(tmp)] [TEMPO]. / Rhodium(II) meso-tetramesitylporphyrin (Rh(tmp)) has been prepared successfully by photolysis of Rh(tmp)Me under anaerobic conditions at low temperature. / The activation of carbon-carbon bond with high reactivity and selectivity has attracted many organometallic chemists due to its fundamental importance in basic chemical research and potential utility in organic synthesis. / The aliphatic, unstrained carbon-carbon bonds of a series of nitroxides 1,1,3,3-tetraalkylisoindolin-2-oxyl have been activated by Rh(tmp). In long chain alkyl substituted nitroxides, regioselective carbon-carbon bond activations were observed. This was attributed to the cooperative effects of the bond dissociation energy and the steric hindrance of alkyl groups in nitroxides. While PPh3 was used as the fifth ligand, the yields of regioselective CCA changed. For sterically less hindered nitroxides, the total yield of CCA increased. For sterically more hindered nitroxides, the total yield of CCA decreased. These can be attributed to the cooperation of steric and electronic effects in the rhodium porphyrin complexes and nitroxides. / The C(sp3)-C(sp3) bonds of a series of alpha-alkylphenylacetonitriles have been activated by Rh(tmp) using PPh3 as the optimized fifth ligand. The activation was not regioselective. The CCA yield was affected by bond energy and steric hindrance of the nitriles. The optimal reaction temperature was 130 °C. / Under same reaction conditions, CCA between Rh(tmp) and 2-alkylbenzonitriles also was carried out. Only C(sp3)-C( sp3) bond was activated. CCA yield depended on the BDE of C-C bond in alkyl substituents. / by Li Xinzhu. / "June 2006." / Adviser: Kin Shing Chan. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6396. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 197-210). / 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, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
12

Competitive aromatic carbon fluorine and carbon hydrogen bond activation by iridium(iii) porphyrins.

January 2011 (has links)
Chan, Chung Yin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 77-80). / Abstracts in English and Chinese. / Table of Contents --- p.i / Acknowledgements --- p.iii / Abbreviations --- p.V / Abstract --- p.vi / Chapter Chapter 1 - --- Introduction --- p.1 / Chapter 1.1 --- Definition of Aromatic Bond Activation --- p.1 / Chapter 1.2 --- History of Carbon-Fluorine Bond Activation --- p.1 / Chapter 2.2.1 --- Examples of Aromatic Carbon-Fluorine Bond Activation in 1970s --- p.1 / Chapter 2.2.2 --- Examples of Aromatic Carbon-Fluorine Bond Activation in 1980s --- p.2 / Chapter 2.2.3 --- Examples of Aromatic Carbon-Fluorine Bond Activation in 1990s --- p.3 / Chapter 2.2.4 --- Examples of Aromatic Carbon-Fluorine Bond Activation in 2000s --- p.6 / Chapter 1.3 --- Difficulties and Challenges in Aromatic Bond Activation Applications of Aromatic Carbon Fluorine Bond Activation --- p.6 / Chapter 2.2.1 --- Thermodynamic Estimations --- p.7 / Chapter 2.2.2 --- Competitive Aromatic Bond Activation --- p.9 / Chapter 1.3.2.1 --- Competitive Aromatic Carbon-Hydrogen and Carbon-Halogen Bond Activation --- p.10 / Chapter 1.3.2.2 --- Competitive Aromatic Carbon-Hydrogen and Carbon-Fluorine Bond Activation --- p.15 / Chapter 1.4 --- Mechanistic Investigations of Aromatic CFA --- p.17 / Chapter 2.2.1 --- Oxidative Addition --- p.17 / Chapter 2.2.2 --- Nucleophilic Aromatic Substitution --- p.18 / Chapter 2.2.3 --- Fluorine Atom Abstraction --- p.19 / Chapter 2.2.4 --- "1,2-Addition" --- p.19 / Chapter 1.5 --- Mechanistic Investigations of Aromatic Carbon-Hydrogen Bond Activation --- p.20 / Chapter 2.2.1 --- Oxidative Addition --- p.20 / Chapter 2.2.2 --- Electrophilic Aromatic Substitution --- p.21 / Chapter 2.2.3 --- "1,2-Addition" --- p.21 / Chapter 1.6 --- Applications of Aromatic Carbon-Fluorine Bond Activation --- p.22 / Chapter 1.7 --- Applications of Aromatic Carbon-Hydrogen Bond Activation --- p.23 / Chapter 1.8 --- Structural Features of Iridium Porphyrins --- p.23 / Chapter 1.9 --- Obj ectives of the Work --- p.25 / Chapter Chapter 2 - --- Competitive Aromatic Carbon Fluorine and Carbon Hydrogen Bond Activation by Iridium(III) Porphyrins --- p.26 / Chapter 2.1 --- C-F Activation of Fluorobenzene by Rhodium(III) Porphyrins --- p.26 / Chapter 2.2 --- Preparation of Starting Materials --- p.26 / Chapter 2.2.1 --- Preparation of Tetratolylporphyrin --- p.26 / Chapter 2.2.2 --- Preparation of Iridium(III) Porphyrin Carbonyl Chloride --- p.27 / Chapter 2.3 --- Base Effect of Carbon-Fluorine Bond Activation --- p.27 / Chapter 2.4 --- Solvent Effect of Carbon-Fluorine Bond Activation --- p.30 / Chapter 2.5 --- Temperature Effect --- p.31 / Chapter 2.6 --- Concentration Effect of Carbon-Fluorine Bond Activation --- p.33 / Chapter 2.7 --- Activations of Fluorobenzenes --- p.33 / Chapter 2.8 --- Electronic Effect --- p.36 / Chapter 2.9 --- Mechanistic Studies --- p.38 / Chapter 2.9.1 --- Activation of Fluorobenzene --- p.38 / Chapter 2.9.2 --- Reaction between Ir(ttp)H and Fluorobenzene --- p.40 / Chapter 2.9.3 --- Reaction between Ir2(ttp)2 and Fluorobenzene --- p.41 / Chapter 2.9.4 --- "Reaction between Ir(ttp)""K+ and Fluorobenzene" --- p.42 / Chapter 2.9.5 --- Reaction between Ir(ttp)Me and Fluorobenzene --- p.44 / Chapter 2.10 --- Proposed Mechanism for CFA --- p.45 / Chapter 2.11 --- Proposed Mechanism for CHA --- p.47 / Chapter 2.12 --- Kinetic and Thermodynamic CFA and CHA Products --- p.47 / Chapter 2.13 --- Summary --- p.48 / Chapter Chapter 3 - --- Experimental Section --- p.49 / Reference --- p.77 / Chapter Appendix I - --- Spectra --- p.81
13

Activation of carbon-carbon bonds of nitroxides and metalloporphyrin alkyls by rhodium porphyrin radical.

January 2001 (has links)
by Tam Tin Lok Timothy. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 75-81). / Abstracts in English and Chinese. / Table of Contents --- p.i / Acknowledgments --- p.iv / Abbreviations --- p.vi / Structural Abbreviations for Porphyrin Complexes --- p.vii / Abstract --- p.viii / Chapter Chapter 1 --- GENERAL INTRODUCTION --- p.1 / Chapter 1.1 --- Carbon-Carbon Bonds Activation by Transition Metal Complexes --- p.1 / Chapter 1.1.1 --- Kinetic and Thermodynamic Considerations in CCA --- p.2 / Chapter 1.1.2 --- C-C Bond Activation in Strained System --- p.3 / Chapter 1.1.3 --- C-C Bond Activation Driven by Aromatization --- p.4 / Chapter 1.1.4 --- C-C Bond Activation of Carbonyl Compounds --- p.5 / Chapter 1.1.5 --- Intramolecular sp2-sp3 C-C Bond Activation in PCP system --- p.8 / Chapter 1.1.6 --- C-C Bond Activation in Homoallylic Alcohol by β-Allyl Elimination --- p.10 / Chapter 1.1.7 --- C-C Bond Activation by Metathesis of Alkanes --- p.11 / Chapter 1.1.8 --- C-C Bond Activation by Nucleophilic Attack of Rhodium Porphyrin Anion --- p.14 / Chapter 1.2 --- Objective of the work --- p.14 / Chapter CHAPTER 2 --- CARBON-CARBON BONDS ACTIVATION (CCA) BY RHODIUM PORPHYRIN RADICAL --- p.16 / Chapter 2.1 --- Serendipitous Discovery of CCA --- p.16 / Chapter 2.1.1 --- Proposed Mechanism of CCA --- p.16 / Chapter 2.2 --- CCA of Rhodium Porphyrin Radical witn Nitroxides --- p.17 / Chapter 2.2.1 --- Synthesis of Rhodium Porphyrins --- p.18 / Chapter 2.2.2 --- Synthesis of Rhodium(II) Porphyrin Radical --- p.19 / Chapter 2.2.3 --- "Synthesis of 1,1,3,3-Tetraalkylisoindolin-2-oxyls" --- p.19 / Chapter 2.2.4 --- Reactions between Rhodium(II) Porphyrin Radical and Nitroxides --- p.21 / Chapter 2.2.5 --- Independent Synthesis of Alkyl Rhodium(III) Porphyrins --- p.24 / Chapter 2.3 --- CCA of Rhodium Porphyrin Radical with Other Substrates --- p.26 / Chapter 2.3.1 --- Reactions between Rhodium(II) Porphyrin Radical and Non-enolizable Ketones --- p.26 / Chapter 2.3.2 --- Reactions between Rhodium(II) Porphyrin Radical and Diketones --- p.27 / Chapter 2.4 --- Ligand Effects on Carbon-Carbon Bonds Activation --- p.28 / Chapter 2.4.1 --- Ligand Coordination between Rhodium(II) Porphyrin Radical --- p.29 / Chapter 2.4.2 --- Phosphine Effects on CCA between Rhodium(II) Porphyrin Radical and Nitroxides --- p.31 / Chapter 2.5 --- Summary --- p.32 / Chapter CHAPTER 3 --- PRELIMINARY MECHANISTIC STUDIES OF CARBON- CARBON BONDS ACTIVATION (CCA) --- p.33 / Chapter 3.1 --- Attempted Mechanistic Studies of CCA --- p.33 / Chapter 3.1.1 --- Proposed Mechanism of CCA via SH2 Pathway --- p.33 / Chapter 3.1.2 --- Homolytic Bimolecular Substitution (Sr2) --- p.33 / Chapter 3.1.3 --- Literature Review on Sh2 Reaction --- p.34 / Chapter 3.1.4 --- Prerequisities on SH2 reactions at Carbon Center --- p.36 / Chapter 3.1.5 --- Kinetic Studies of CCA between Rh(tmp) and TEMPO…… --- p.37 / Chapter 3.2 --- Stereochemical Test for CCA --- p.39 / Chapter 3.2.1 --- Objective of the Stereochemical Test --- p.39 / Chapter 3.2.2 --- Synthesis of Alkyl Rhodium(III) Porphyrins --- p.42 / Chapter 3.2.3 --- Alkyl Exchange Reactions with Rh(por)R --- p.42 / Chapter 3.3 --- Summary --- p.43 / Chapter CHAPTER 4 --- EXPERIMENTAL SECTION --- p.45 / CONCLUSION --- p.74 / REFRENCES --- p.75 / LIST OF SPECTRA --- p.82 / SPECTRA --- p.83
14

Competitive aromatic carbon fluorine bond activation and carbon hydrogen bond activation of fluorobenzenes by rhodium (III) porphyrins.

January 2009 (has links)
Lee, Man Ho. / Thesis submitted in: October 2008. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 78-83). / Abstracts in English and Chinese. / Table of Contents --- p.ii / Acknowledgements --- p.iv / Abbreviations --- p.v / Abstract --- p.vi / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Definition of Aromatic Bond Activation --- p.1 / Chapter 1.2 --- Application of Aromatic Carbon Fluorine Bond Activation --- p.1 / Chapter 1.3 --- Mechanistic Schemes Involved in Aromatic Bond Activation --- p.2 / Chapter 1.4 --- Difficulties in Aromatic Bond Activation --- p.7 / Chapter 1.5 --- Competitive Bond Activations --- p.20 / Chapter 1.6 --- Structural Features of Rhodium Porphyrins --- p.27 / Chapter 1.7 --- Objective of the Work --- p.28 / Chapter Chapter 2 --- Competitive C-F and C-H Activation of Fluorobenzenes by Rhodium(III) Porphyrins / Chapter 2.1 --- C-F Activation of Fluorobenzene by Rhodium(III) Porphyrins --- p.29 / Chapter 2.2 --- Preparation of Starting Materials --- p.29 / Chapter 2.3 --- Base Effect of CFA --- p.30 / Chapter 2.4 --- Solvent Effect of CFA --- p.32 / Chapter 2.5 --- Temperature Effect of CFA Reaction --- p.34 / Chapter 2.6 --- Activations of Fluorobenzene --- p.35 / Chapter 2.7 --- Electronic Effect of Carbon-Fluorine Bond Activations --- p.38 / Chapter 2.8 --- Preliminary Mechanistic Studies --- p.39 / Chapter 2.9 --- Proposed C-F Activation Mechanism --- p.44 / Chapter 2.10 --- Proposed C-H Activation Mechanism --- p.48 / Chapter 2.11 --- Summary --- p.51 / Chapter Chapter 3 --- Experimental Section --- p.56 / References --- p.78 / Table of Content of Appendix --- p.83 / Appendix I Crystal Data and Processing Parameters --- p.85 / Appendix II Spectra --- p.91
15

Noble and transition metal aromatic frameworks synthesis, properties, and stability /

Carson, Cantwell G. January 2009 (has links)
Thesis (Ph. D.)--Materials Science and Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Rina Tannenbaum; Committee Co-Chair: Rosario A. Gerhardt; Committee Member: E. Kent Barefield; Committee Member: Karl I. Jacob; Committee Member: Preet Singh; Committee Member: R. Bruce King. Part of the SMARTech Electronic Thesis and Dissertation Collection.
16

Noble and transition metal aromatic frameworks: synthesis, properties, and stability

Carson, Cantwell G. 14 May 2009 (has links)
In the first section, the electrical conductivity of rhodium phenylene-diisocyanide polymer is reported to be 3.4E-11 S/cm. However, the conductivity also exhibits an inverse exponential decay in air with t = 8 days. This change is attributed to the oxidation of the isocyanide functional group to an isocyanate, leading to degradation in the long-range metal-metal bonding, the dominant conductivity mechanism. Using a more stable carboxylate ligand, the Cu terephthalate (TPA) system is studied and compared against the Mg, Co, Ni, and Zn terephthalates. A synthesis in N,N-dimethylformamide (DMF) is developed and large quantities of the Cu(TPA)DMF can be synthesized in air. The crystal structure of the Cu(TPA) DMF is shown to be in the C2/m spacegroup. Upon desolvation, the Cu(TPA) is shown to have a large surface area of 625 m2/g. The magnetic susceptibility of the Cu(TPA) indicates anti-ferromagnetic coupling between adjacent Cu centers in the same dimer. The thermal stability of the Zn, Ni, Co, and Mg terephthalates is shown to increase with decreasing symmetric carboxylate stretch in the IR. The magnetic susceptibilities of the Co and Ni terephthalates have paramagnetic behavior, with a Weiss temperature of T = -12.9 K and T = 8.8 for Co(TPA) DMF and Ni(TPA)DMF respectively. A heterometallic Zn-Cu terephthalate is synthesized with Cu concentrations ranging from 0 to 100%. Upon the addition of Cu, Zn-rich frameworks increase in surface area, change in thermal stability, and increase their solvent retention from 16% to 25%. Zn is shown to couple with Cu in the same dimer at a high rate, changing the behavior of the dimer from anti-ferromagnetic to paramagnetic. The Weiss temperature suggests weak ferromagnetic interaction.

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