Stepwise Activation of E–H (E = Si, Ge) Bonds at Adjacent Rhodium and Iridium Centres

• Author / Creator

  Mobarok, Md Hosnay

• Transition metal-mediated E–H (E = Si, Ge) bond activation plays a pivotal role in industrially important processes, such as hydrosilylation and dehydrogenative coupling of organosilanes. Activation of these bonds by mono-metallic complexes is well studied, however, E–H bond activations in bimetallic complexes, especially complexes containing two different metals, and their subsequent reactivities, have been less well studied. This thesis probes the activation of Si–H and Ge–H bonds in a variety of organosilanes and organogermanes by bimetallic complexes involving Rh/Ir metal combination.
  The second and third Chapters of this thesis explore the reactivity and mechanistic details of incorporation of multiple units of silicon- (Chapter 2) and germanium-containing (Chapter 3) functionalities in dppm-bridged (dppm = Ph2PCH2PPh2) complexes of Rh/Ir via stepwise activation of Si–H and Ge–H bonds. A number of intermediates are characterized either in situ (by low-temperature NMR spectroscopy) or isolated during these transformations. The subsequent reactivity of one cationic germylene-bridged complex has also been demonstrated in Chapter 3.
  A synthetic protocol is outlined in Chapter 4 for the selective incorporation of two different μ-silylene units, and the influence of the substituents and π-stacking interactions on the Si---Si distance (determined by X-ray crystallography) in this series and the implications related to the nature of the Si---Si interactions are discussed. By using a similar synthetic strategy a series of (μ-silylene)/(μ-germylene) complexes have also been synthesized.
  Finally in Chapter 5, Si–H bond activations of silanes have been studied in a Rh/Ir complex bridged by an electronically rich and less-sterically hindered bridging ligand, depm (depm = Et2PCH2PEt2).

• Subjects / Keywords

  • Bimetallic Activation
  • Bridging-silylene
  • Bridging-germylene

• Graduation date

  Fall 2012

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3B122

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.