|dc.description.abstract||The synthesis and characterization of the first series of tetra-NHC-Ag(I)-X cubane clusters are reported. The clusters were characterized with 1H and 13C NMR spectroscopy, ESI-TOF MS, and single crystal X-ray diffraction. Crossover experimental data were consistent with intramolecular exchange, which can be visualized by a molecular rotating type mechanism.
Additionally, CCC-NHC Zr(IV) pincer type complexes were synthesized and characterized with 1H and 13C NMR spectroscopy, CHN combustion analysis, and X-ray crystallography. A large rate effect was observed based on the halogen and metal center for the hydroamination/cyclization of unactivated aminoalkenes. Zirconium based pincers provided faster reaction rates than their hafnium counterparts (Zr>Hf). Precatalysts with iodide ligands provided faster reaction rates than their bromide and chloride counterparts (I>Br>Cl). The mechanism of hydroamination for Zr(IV) CCC-NHC complexes was also investigated for bis(iodide) and bis(amido) ligand classes. A full kinetic analysis of substrate and precatalyst have been identified along with the formation of small amounts of an oxidized product. The proposed mechanism contains an imido-type intermediate whose formation depends greatly on which set of ligand class is used.||