New architectures in imidazol-2-ylidene chemistry

This dissertation consists of three chapters. The first chapter details the history that led to the isolation of first stable carbene, the methods of producing stable carbenes, and their metal complexes. This chapter also contains a comparative study of di- and tetrasubstituted imidazol-2-ylidenes.; Chapter 2 deals with the synthesis of a hexafluoroalcoholate functionalized imidazol-2-ylidene and its corresponding metal complexes. A series of metal complexes derived from the targeted carbene was synthesized and fully characterized. The applications of these complexes in catalysis were also investigated.; Chapter 3 details the synthesis toward the novel cyclopentadienyl annulated imidazol-2-ylidenes and their metal complexes. Metallocenes fused imidazol-2-thiones and imidazolium salts, the carbene precursors, were synthesized and characterized. A variety of conditions for production of free metallocenes fused carbenes were not successful. These carbenes may be too electron rich to allow easy isolation. However, mercury and palladium complexes of a ruthenocene fused carbene were synthesized and characterized. Preliminary catalytic studies shows that a mixed palladium-ruthenium complex is an active catalyst for Suzuki-coupling reactions in aqueous medium.