Quantum Chemistry Modeling of Homogeneous First-Row Transition Metal Catalysis

by Yaqun Zhu

Institution: University of Pittsburgh
Year: 2015
Posted: 02/05/2017
Record ID: 2117167
Full text PDF: http://d-scholarship.pitt.edu/25726/1/Yaqun_Thesis.pdf


Catalysts accelerate rates of chemical reactions, and there is great interest in identifying catalysts that are effective, stable, and economical. This thesis reports two homogeneous chemical reaction mechanism studies using first principles quantum chemistry. The goal of this work is to understand the fundamental reaction pathways that reactions occur, so that one might eventually make improved catalysts. A cobalt-based catalyst system was recently reported for CO2 hydrogenation to form formate.1 It was hypothesized that a cooperative bifunctional catalyst involving an N-heterocyclic carbene (NHC) and this cobalt-based catalyst might further improve this chemistry. We investigated the likelihood that the NHC could function either as a Brønsted base to deprotonate a metal hydride or dihydrogen intermediate, or as a Lewis base to activate carbon dioxide towards nucleophilic attack. We also investigated fundamental catalysis involving heterobimetallic catalysts. We elucidated a complete mechanistic pathway for C−H boralytion with Cu−Fe catalysts to explain experimental observations and suggest improvements to the catalyst. This thesis aims to provide useful insight into canonical organometallic reaction mechanisms involved in bimetallic catalysts.