Investigating the chemistry of cationic rhodium bisphosphine complexes: comparing reactivity in the solid state with solution

Pike, SD

Oxford Thesis Collection

Thesis

Investigating the chemistry of cationic rhodium bisphosphine complexes: comparing reactivity in the solid state with solution

Abstract:: This thesis describes the synthesis and characterisation of a series of cationic rhodium bis-phosphine complexes. The reactivity of these new complexes in the solid-state and in solution is reported.

In Chapter 2 the synthesis of a series of rhodium bis-phosphine diene complexes is presented and the reactions of these complexes with hydrogen in the solid-state are investigated. Several examples of zwitterionic complexes coordinating the [BAr^F4]^─ anion are produced by hydrogenation. A rare example of a sigma-alkane complex, [Rh(ⁱBu₂PCH₂CH₂PⁱBu₂)(eta²-_CH-eta²-_CH-NBA][BAr^F4]^─
iBu₂PCH₂CH₂PⁱBu₂)(eta²-_CH-eta²-_CH-NBE][BAr^F4] may form as a short lived intermediate prior to the formation of the sigma-alkane complex. The temporal evolution of the solid-state hydrogenation reactions is monitored by powder X-ray diffraction methods.
In Chapter 3 the C−X activation of various aryl halides using the [Rh(ⁱBu₂PCH₂CH₂PⁱBu₂)]⁺ fragment is reported. The 'ligand innocence' of the phosphine with respect to intramolecular C−H activation is also discussed. A rare example of C−X activation in the solid-state is presented, which shows the formation of an isomer that is not observed by analogous solution routes.

Chapter 4 investigates solid-state ligand exchange reactions using ethene, butadiene, CO and NH3 gases. A solid-state transfer dehydrogenation reaction is reported within single crystals of [Rh(ⁱBu₂PCH₂CH₂PⁱBu₂)(C₂H₄)₂][BAr^F4]. H/D exchange of NH3 can also occur in the solid state in the bis-ammonia complex [Rh(ⁱBu₂PCH₂CH₂PⁱBu₂)(NH₃)₂][BAr^F4]. A variety of rhodium complexes are tested as heterogeneous catalysts for the hydrogenation of ethene and the isomerisation of butene.

In Chapter 5 the binding affinity of a variety of fluorinated arenes to rhodium bis-phosphine fragments is presented using ESI-MS methods. The dependence upon the arene substituents, phosphine substituents and phosphine bite angle are discussed.

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APA Style

Pike, S. D. (2014). Investigating the chemistry of cationic rhodium bisphosphine complexes: comparing reactivity in the solid state with solution [PhD thesis]. University of Oxford.

MLA Style

Pike, SD. Investigating the Chemistry of Cationic Rhodium Bisphosphine Complexes: Comparing Reactivity in the Solid State with Solution. 2014. University of Oxford, PhD thesis.

Chicago Style

Pike, SD. 2014. “Investigating the Chemistry of Cationic Rhodium Bisphosphine Complexes: Comparing Reactivity in the Solid State with Solution.” PhD thesis, University of Oxford.
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