Described in this thesis are the investigations into the chemistry of N-heterocyclic carbene (NHC) ligands and transition-metal complexes thereof. Specifically, a variety of N-heterocyclic carbene complexes of nickel were prepared, characterized and used as catalysts in three types of homogeneous catalytic processes. First, nickel(II) complexes of monodentate NHC ligands were successfully used as catalysts in the hydrosilylation of internal alkynes. Second, nickel(II) complexes bearing bidentate N-heterocyclic carbene ligands or functionalized NHC ligands were shown to be highly effective in the Kumada coupling of aryl halides with aryl Grignard reagents. In addition, the nickel-catalyzed Kumada coupling was investigated using quantum-chemical calculations. Finally, all three types of nickel complex were tested for their catalytic activity in the vinyl polymerization of norbornene. Furthermore, a silv er(I) NHC complex was isolated, characterized and used in the preparation of a nickel(II) NHC complex.UBL - phd migration 201
