| Metal complexes are involved in a wide variety of chemical transformations and processes vital to both industry and life. The study of the mechanisms of these transformations as well as the intermediate species involved is crucial to understanding and improving today's catalysts. However, the study of these species and their reactions is often complicated by the transient nature of the reactive intermediates involved. Furthermore, the nature of the solution phase means that there are typically several species present in a reaction mixture, further complicating the study of these species. In this work gas phase vibrational spectroscopy techniques are used to isolate and investigate catalytically relevant complexes.;In the first part of this work the behavior of hydrated MOH+ clusters is investigated. These clusters, which serve to model interactions present in water oxidation intermediates, display a surprising dependence of the OH- vibrational frequency on the identity of the metal center. This effect is attributed to a vibrational stark effect which is modulated by charge transfer between the OH- moiety and metal center. Further solvation of the complexes is found to further modulate this shift.;In the second section we investigate the interactions present in a series of deprotonated glycine polypeptides as well as the behavior of two copper-glycine polypeptide complexes, one of which, [CuGly4-4H]2- , has been shown to have catalytic activity in water oxidation reactions. In the case of the polypeptides the chain length is shown to have a significant influence on the interactions observed between the NH2, COO -, and amide N-H moieties. Surprisingly, the interaction between amide NH groups and the terminal NH2 group is shown to have a profound effect on the stability and structure of the 3 and 4 residue peptides. In the case of the Cu-polypeptide complexes the peptide species bind to the copper in a planar fashion. Furthermore, the structure we observe for [CuGly 4-4H]2- is significantly different than that observed in previous solution phase studies.;Finally, we investigate the reaction of a platinum complex with methane. This reaction, which is an important step in the activation of alkane C-H bonds, is performed using our new cryogenic reaction trap. The resulting vibrational characterization shows that we have isolated the elusive sigma-CH intermediate. This intermediate, which has been implicated in the selectivity of the C-H activation reaction, has never been directly observed in a reaction until now. The other postulated intermediate species, however, are not observed under these conditions. |
