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

Author: Del Ciello, Sarah Anne

Year: 2020

Degree: Dissertation (Ph.D.)

Advisor: Gray, Harry B.

Committee Members: Reisman, Sarah E.; Gray, Harry B.; Peters, Jonas C.; See, Kimberly

Option: Chemistry

DOI: 10.7907/6QTC-G360

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 RuII/III couple can be tuned without drastic modification of the diimine0/- 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.

Files