Density functional theory investigations of the ground- and excited-state chemistry of dinuclear organometallic carbonyls

In this dissertation, various dinuclear organometallic carbonyls (DOCs)---that is, compounds containing two metal atom centers, each bonded to one or more CO ligands---are used to evaluate, both qualitatively and quantitatively, the strengths, weaknesses, possibilities, and limitations of density functional theory (DFT). This evaluation largely concerns itself with the ability of DFT to provide insight and data of relevance to inorganic chemists. The accuracy of DFT as applied to both ground-state and electronically excited-state systems is explored. The first chapter primarily concerns the ability of DFT to distinguish between different isomers of a given molecule, based on both relative stabilities as calculated by DFT and through comparisons between experimentally observed and computationally simulated vibrational absorption spectra. It is shown that calculations of this sort can aid experimental inorganic chemists in a number of ways, including verification of proposed structures, discernment between likely possible structures, and even identification of previously undetermined structures. The accuracy is such that it is even possible to assign the individual infrared peaks of multicomponent systems to their sources. In the second chapter, the precision of DFT is rigorously quantified, using these DOC compounds, and a procedure ideally suited for computational inorganic chemistry is recommended. The following chapter provides similar recommendations for investigations into excited-state chemistry, using the recent methodology of time-dependent density functional theory (TD-DFT). Finally, the procedures are applied to another common DOC, known colloquially as Fp dimer. For this compound, as well as for certain analogues, insight into the complicated solution-phase behavior and photochemistry is afforded through the use of the accurate DFT and TD-DFT approaches explored in the previous chapters. It is expected that the results and recommendations presented herein will be of great use to any inorganic chemist who would seek to address problems that are not easily amenable to experimental study, that show contradictory experimental results, or that are merely in need of verification. The accuracy demonstrated for DFT in this work shows that this computational technique is more than adequate for the task of addressing these concerns.