Carbon-Carbon Bond Formation and Unexpected Carbon-Hydrogen Bond Activation at Adjacent Metal Centres

• Author / Creator

  MacDougall, Tiffany J

• The formation of carbon–carbon (C–C) bonds is central to the transformation of small, readily available hydrocarbons into value-added products with useful chemical and physical properties. An important industrial process involving C–C bond formation is the Fischer-Tropsch (FT) process which converts carbon monoxide and hydrogen into a range of useful hydrocarbons. Although this heterogeneous process is not well understood, the importance of surface-bound, bridging methylene groups in this process is recognized.
  This dissertion seeks to gain a further understanding of the chemistry of bridging methylene groups. Chapter 2 of this thesis explores the formation of C–C bonds by a methylene-bridged Ir/Ru system through the coupling of methylene groups with cumulene substrates. Although C–C bond formation is observed in these complexes, we also observe unexpected multiple C–H bond activations, including the unusual activation of geminal C–H bonds in olefins. In Chapter 3, we report the C–H activation of cumulenes, conjugated dienes, and monoolefins, by the tetracarbonyl Ir/Ru complex and a mechanism is presented for these activations.
  The original goal of C–C bond formation is revisited in Chapters 4 and 5 as we report the reactivity of the methylene-bridged Ir/Os complex with unsaturated substrates towards hydrocarbyl-bridged complexes. This metal combination appears to be a better model for FT chemistry, owing to the strong metal–carbon bonds. The reactivity of the tetracarbonyl Ir/Os complex is also reported with unsaturated substrates (Chapter 5), as a comparison to the Ir/Ru analogue.
  The reactivity of the Ir/M (M = Ru, Os) systems are compared to the analogous Rh/M (M = Ru, Os) systems, describing the effects of changing the group 8 metal, the group 9 metal, or both. Throughout this thesis, we attempt to elucidate the roles of the adjacent metals in C–C bond formation and C–H bond activation.

• Subjects / Keywords

  • Adjacent metal centres
  • Carbon-carbon bond formation
  • Carbon-hydrogen bond activation
  • Bimetallic complexes

• Graduation date

  Spring 2012

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3BM4P

• 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.