Ab Initio Modeling of the Structures and Catalytic Properties of Selected Mononuclear, Dinuclear, Supramolecular, and Periodic Metal-Organic Complexes

Abstract

Numerous varieties of metal-organic compounds have been synthesized to date, ranging in size from complexes containing only one or two metal atoms to supramolecular clusters, cages, and periodic latices. Metal-organic compounds can be tuned for a multitude of applications by modifying organic ligands and metal centers to select for desired size, shape, and electronic properties. Because of the complicated nature of many such systems, characterization of them can be a challenge. Mechanisms of reactivity, too, are notoriously difficult to characterize experimentally; as the saying goes, "If you can isolate the species, it probably isn't important to the mechanism." Theory can be of assistance in both cases. Herein, we investigate the properties of a variety of metal-organic systems, including mononuclear and dinuclear ruthenium water oxidation catalysts, supramolecular Cu(I) and Fe(II) host-guest complexes, and a metal-organic framework modified with single-site Ni(II) and Co(II). In each case, we are able to use \textit{ab initio} methods to provide some valuable insight into the system: for the water oxidation catalysts, we examine the effects on catalytic efficacy of modifications to the ligand systems in order to advise the development of even better catalysts; for the host-guest complexes, we help to explain the binding trends observed between small molecules that incorporate into the internal cavities of the cages; and for the metal-organic framework, we take steps toward elucidating the structure resulting from deposition of Ni(II), as well as giving insight into the mechanisms by which the deposited metals catalyze ethylene hydrogenation and oligomerization.