Kinetic Studies of Hydrogen Oxidation by Cobaloximes and Synthesis, Spectroscopy and Boronation of a New Heteroleptic Ruthenium Cyanide Complex

Citation

Del Ciello, Sarah Anne (2020) Kinetic Studies of Hydrogen Oxidation by Cobaloximes and Synthesis, Spectroscopy and Boronation of a New Heteroleptic Ruthenium Cyanide Complex. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/6QTC-G360. https://resolver.caltech.edu/CaltechTHESIS:11152019-095230239

Abstract

Cobaloximes are macrocyclic complexes well-studied as homogeneous catalysts for hydrogen evolution, but they are also competent at the microscopic reverse reaction, hydrogen oxidation. Kinetic studies of Co(dmgBF₂)₂L₂ reacting with hydrogen and base reveal a rate law that is second-order in cobalt and first-order in H₂, indicating that the mechanism of H-H bond breaking is homolytic.

The reduction potentials of metal cyanide complexes can be tuned by appending boranes to the N-terminus. By boronating ruthenium cyanide complexes containing diimine ligands, the Ru^II/III couple can be tuned without drastic modification of the diimine^0/- couple. A new member of the [Ru(dimmine)(CN)4]^2- family is synthesized with the ligand 4,4’-bis(trifluoromethyl)-2,2’-bipyridine (^CF3bpy) and boronated, resulting in a molecule with two reversible redox events separated by 3.2 V.

Thesis Files