The electronic structure factors that control Si-H and Ge-H bond activation by transition metals are investigated by means of photoelectron spectroscopy. Molecular orbital calculations are also used to gain additional insight into the orbital interactions involved in bond activation. The complexes studied have the general molecular formula (η⁵-C₅R'₅)Mn(CO)(L)HER₃, where R' is H or CH₃, L is CO or PMe₃, E is Si or Ge and R is Ph or Cl. These compounds are interesting models for catalysts in industrial processes like hydrosilation. The compounds display different stages of interaction and "activation" of the E-H bonds with the metal. One purpose is to measure the degree of Mn, Si, H 3-center-2-electron bonding in these complexes. The three-center interaction can be tuned by changing the substituents on Si, methylating the cyclopentadienyl ring, changing the ligand environment around the metal and substituting Si with Ge. The degree of activation is measured by observing the shifts in the metal and ligand ionizations relative to starting materials and free ligand in the photoelectron spectrum. Changing the substituent on Si extensively changes the degree of activation. Photoelectron spectral studies on (η⁵-C₅H₅)Mn(CO)₂HSiPh₃ show this to be a Mn(I) system. Progressive methylation of the cyclopentadienyl ring increases the electron richness at the metal center with no substantial effect on the degree of activation. Substitution on the metal (PMe₃ for CO) is less able to control the electronic structure factors of activation than the substitution on the Si atom. The magnitude of Ge-H bond activation is found to be of the same order as the Si-H bond activation for analogous compounds as found by studying (η⁵-C₅H₅)Mn(CO)₂HGePh₃, (η⁵-CH₃C₅H₄)Mn(CO)₂HGePh₃ and (η⁵- C₅(CH₃)₅)Mn(CO)₂HGePh₃ complexes by photoelectron spectroscopy. The photoelectron spectra of CpFe(CO)₂SiCl₃ and CpFe(CO)₂SiMe₃ were measured to study the electron charge shift from the metal to the ligand in these complexes as compared to CpMn(CO)₂HSiR₃ complexes. The photoelectron spectroscopic studies include numerous perturbations of the ligand and metal center to observe the extent of bond interaction and remain one of the best techniques to detect activation products.

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Lau Cheuk Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 93-98). / Abstracts in English and Chinese. / Table of Contents --- p.i / Acknowledgements --- p.iii / Abbreviations --- p.iv / Structural Abbreviations for Porphyrin Complexes --- p.v / Abstract --- p.vi / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- General Introduction --- p.1 / Chapter 1.2 --- Activation of Carbon-Hydrogen Bond (CHA) by Transition Metal --- p.2 / Chapter 1.2.1 --- Application of CHA by Transition Metals --- p.3 / Chapter 1.2.2 --- Thermodynamic in CHA by Transition Metals --- p.5 / Chapter 1.2.3 --- Types of Carbon-Hydrogen Activations --- p.6 / Chapter 1.3 --- Carbon-Hydrogen Bond Activation of Aldehydes --- p.14 / Chapter 1.3.1 --- Catalytic Application of CHA of Aldehydes by Transition Metals --- p.14 / Chapter 1.3.2 --- Stability of Intermediate M(COR) --- p.15 / Chapter 1.3.3 --- Issue in Selectivity --- p.16 / Chapter 1.4 --- Structural Features of Rhodium Porphyrins --- p.23 / Chapter 1.5 --- Objective of the work --- p.24 / Chapter Chapter 2 --- Carbon-Hydrogen Activation of Aldehydes by Rh(ttp)Cl and Rh(ttp)Me / Chapter 2.1 --- Introduction --- p.26 / Chapter 2.2 --- CHA of Aldehydes by Rh(ttp)Cl --- p.27 / Chapter 2.2.1 --- Preparation of Rh(ttp)Cl --- p.27 / Chapter 2.2.2 --- Solvents Screening --- p.27 / Chapter 2.2.3 --- Results and Discussion --- p.30 / Chapter 2.3 --- CHA of Aldehydes by Rh(ttp)Me --- p.33 / Chapter 2.3.1 --- Preparation of Rh(ttp)Me --- p.34 / Chapter 2.3.2 --- Results and Discussion --- p.35 / Chapter 2.4 --- Mechanistic Studies --- p.37 / Chapter 2.4.1 --- CHA of Aldehydes by Rh(ttp)Cl --- p.37 / Chapter 2.4.2 --- CHA of Aldehydes by Rh(ttp)R --- p.42 / Chapter 2.5 --- Comparison of the u(C=0) --- p.48 / Chapter 2.6 --- X-ray Data --- p.49 / Chapter 2.7 --- Summary --- p.50 / Chapter Chapter 3 --- CHA of Aldehydes by Rh(ttp)CH2CH2OH and Rh(ttp)+X- / Chapter 3.1 --- Introduction --- p.52 / Chapter 3.2 --- CHA of Aldehydes by Rh(ttp)CH2CH2OH --- p.53 / Chapter 3.2.1 --- Results and Discussion --- p.53 / Chapter 3.2.2 --- Mechanistic Studies --- p.61 / Chapter 3.3 --- CHA of Aldehydes by Rh(ttp)+X- --- p.65 / Chapter 3.4 --- Summary --- p.67 / Conclusion --- p.68 / Experimental --- p.69 / Reference --- p.93 / Appendix I Crystal Data and Processing Parameters --- p.99 / List of Spectra --- p.141 / Spectra --- p.143

Base-promoted CHA of unstrained alkanes with 5,10,15,20-tetratolylporphyrinatorhodium complexes, Rh(ttp)X (X = Cl, H, Rh(ttp)), has been achieved. Rh(ttp)Cl, reacted with n-pentane, n-hexane, n-heptane, c-pentane and c-hexane in the presence of potassium carbonate at 120 °C in 6 to 24 h to give rhodium porphyrin alkyls, Rh(ttp)R, in 29--76% yields. Mechanistic investigations suggested that Rh 2(ttp)2 and Rh(ttp)H are key intermediates for the parallel CHA step. The roles of base are (i) to facilitate the formation of Rh(ttp)Y (Y- = OH-, KCO3 -), (ii) to enhance the CHA rate with alkane and generate Rh(ttp)H by a Rh(ttp)Y species which is more reactive than Rh(ttp)Cl, and (iii) to provide a parallel CHA pathway by Rh2(ttp)2. / c-Octane reacted with Rh(ttp)Cl at 120 °C in 7.5 h in the presence of K2CO3 to yield Rh(ttp)( n-octyl) and Rh(ttp)H in 33% and 58% yields, respectively. Mechanistic investigations indicate that the CCA product is generated from the Rh II(ttp)-catalyzed 1,2-addition of c-octane with Rh(ttp)H. Reaction of c-octane and Rh(ttp)H/Rh2(ttp) 2 (10:1) selectively yielded Rh(ttp)(n-octyl) in 73% at 120 °C in 15 h. The catalyst RhII(ttp) radical cleaves the C-C bond of c-octane to form to a Rh(ttp)-alkyl radical, which then abstracts a hydrogen atom from Rh(ttp)H to generate the Rh(ttp)( n-octyl), and subsequently leading to regeneration of the Rh II(ttp) radical. (Abstract shortened by UMI.) / K2CO3-promoted CHA of the ring-strained cycloheptane with Rh(ttp)Cl at 120 °C in 6 h gave the CHA product Rh(ttp)( c-heptyl) and together with, unexpectedly, the CCA product Rh(ttp)Bn, in 30% and 24% yields, respectively. Mechanistic studies revealed that Rh(ttp)( c-heptyl) undergoes beta-hydride elimination in neutral condition or beta-proton elimination in basic condition followed by reprotonation to give rhodium(III) porphyrin hydride, Rh(ttp)H, and c-heptene. Successive base-promoted CHA of c-heptene with Rh(ttp)H, followed by beta-proton elimination, generates cycloheptatriene. The CHA of cycloheptatriene with Rh(ttp)H formed Rh(ttp)(c-heptatrienyl), which underwent rearrangement with carbon-carbon cleavage at 120 °C in 16 d to yield Rh(ttp)Bn in 96% yield. / The objectives of this research focus on the investigation of carbon-hydrogen bond activation (CHA) and carbon-carbon bond activation (CCA) of alkanes by rhodium porphyrin complexes as well as the mechanistic understanding. / Chan, Yun Wai. / Adviser: Kin Shing Chan. / Source: Dissertation Abstracts International, Volume: 73-02, 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, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Lo, Kwok Cheung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 114-118). / Abstracts in English and Chinese. / Thesis / Assessment Committee --- p.ii / ABSTRACT --- p.iii / ACKNOWLEDGEMENTS --- p.v / TABLE OF CONTENT --- p.vi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Theoretical Background --- p.5 / Chapter Chapter 3 --- Results --- p.38 / Chapter Chapter 4 --- Discussion and Concluding Remarks --- p.85 / LIST OF TABLES / Table / Table la Electronic energies and geometrical parameters of scandium dicarbide by B3LYP/LANL2DZ and B3LYP/LANL2DZ-d --- p.41 / Table lb Comparison of literature results with current computational results of cyclic scandium dicarbide at equilibrium state by B3LYP/LANL2DZ and B3LYP/LANL2DZ-d --- p.42 / Table lc Comparison of literature results with current computational results of linear scandium dicarbide at equilibrium state by B3LYP/LANL2DZ and B3LYP/LANL2DZ-d --- p.43 / Table 2a Electronic energies and geometrical parameters of titanium --- p.46

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Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 189-196).

This thesis has involved an attempt to form a germanium-carbon bond through the reaction of germanium compounds with dilithium phthalocyanine, metal-free phthalocyanine, methyl magnesium iodide, phenyl magnesium bromide, and 1,3-diiminoisoindoline. The reaction products were examined in several ways to help establish their identity. Chemical and spectroscopic analyses were used to determine the nature of the two trans groups in the phthalocyanine compounds. Infrared spectra implied the formation of the germanium-carbon bond.Ball State UniversityMuncie, IN 47306

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