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Carbon-Hydrogen and Carbon-Fluorine Bond Activation Promoted by Adjacent Metal Centres
- Author / Creator
- Slaney, Michael E
The facile cleavage of relatively inert chemical bonds followed by their functionalization into value-added products is an important goal in chemistry. Although monometallic complexes are effective at both the cleavage of inert bonds and the subsequent functionalization of the activated substrates, it is intriguing to consider the influence a second metal can have in promoting reactivity not commonly observed in monometallic systems.
This dissertation explores the roles that metal-metal cooperativity and ancillary diphosphine ligands play in the selective C–H bond activation of α-olefins and C–F bond activation of fluoroolefins. Two unique bimetallic systems, bridged by bis(diphosphine) ligands, are the focal point for this study, with the first system containing the bis(diphenylphosphino)methane (dppm) ligand (Chapters 2 and 3), while the second uses the smaller, more basic bis(diethylphosphino)methane (depm) ligand (Chapters 4 and 5). We compare both ligand systems, emphasizing the steric and electronic factors, and how they influence the C–H bond activation of α-olefins and the C–F bond activation of fluoroolefins.
In Chapter 2, methods for the selective C–F activation of trifluoroethylene when bridging two metal centres are reported under a variety of conditions followed by functionalization of the activated fluorocarbyl fragments through fluorine replacement by either hydrogen or a methyl group. Chapter 3 explores the different methods for fluoride-ion abstraction from bridging 1,1-difluoroethylene and tetrafluoroethylene units and the subsequent functionalization of the fluorocarbyl units produced. The different reactivities of the three fluoroolefins are described.
Chapter 4 outlines the syntheses of depm-bridged complexes of Ir2, Rh2 and IrRh and initial reactivity studies involving these complexes, highlighted by the facile activation of both geminal C–H bonds of α-olefins by one compound. Finally, Chapter 5 describes the reactivity of fluoroolefins (vinyl fluoride, 1,1-difluoro-, trifluoro- and tetrafluoroethylene) with a depm-bridged Ir2 complex, with emphasis on the role of water in the activation processes, the difference in reactivity between the fluoroolefins studied, and the differences of complexes having either dppm or depm as an ancillary ligand.
- Graduation date
- Spring 2012
- Type of Item
- Doctor of Philosophy
- 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.