The Interplay Between Anions And Radicals In Synthesis, Spectroscopy, And Catalysis

Grace Banks Panetti, University of Pennsylvania

Abstract

This dissertation describes studies in the fields of lanthanide-containing heterobimetallic complexes, organic super-electron donors, CeIV–C bonds, and titanium photocatalysts. In all cases, reactive species were isolated and studied via a combination of single crystal X-ray diffractometry, electrochemistry, NMR spectroscopy, and reactivity. These studies were developed to understand new fundamental bonding between new types of bonds or to understand these species role in reactivity. Either the presence of CuI cations in the secondary coordination sphere or the use of sulfur donor atoms in the primary coordination sphere resulted in unusual architectures in the Shibasaki rare earth alkali metal BINOLate (REMB) framework. In CuI containing REMBs an atypical 2 coordinate cation was detected in the secondary coordination sphere. Isolation of an unprecedented anionic REMB species was observed in the case of sulfur-based ligands. Isolation of 2-azaallyl anions enabled electrochemical studies and the isolation of an elusive 2-azaallyl radical. Investigations of single-electron mechanisms related to alkylation and arylation appear to follow the previously proposed mechanisms; however, the mechanism of vinylation was evidently more complicated than previously proposed. Next, our successful synthesis and isolation of a compound containing a CeIV–Caryl bond enabled the investigation of the complex by 13C NMR and computation. These studies determined that the CeIV–Caryl bond displayed significant covalency. The use of the TiCl62- dianion towards photolytic C–H functionalization of hydrocarbons is also described. The photo-reactivity of TiCl62- allows for the activation of hydrocarbons, including methane. Mechanistic investigations, including the isolation and characterization of relevant TiIII species, revealed how a broader substrate scope than the related CeCl62- system was achieved. We expect that these studies will have impact on many different fields of chemistry including both organic and inorganic synthesis, catalysis, and spectroscopy.