Group 5 Metal-Metal Bonds

Metal-metal bonds are found in wide varieties of dinuclear and polynuclear species with or without bridging ligands. This chapter reviews the synthesis, structure, and reactivity of distinct group 5 metal-metal bonded dinuclear and coordinatively unsaturated organodimetallic complexes. In spite of a large amount of work in the area of divanadium compounds-preparation, nonorganometallic metal-metal bonded divanadium complexes are limited due to the absence of suitable metal-metal bonded divanadium precursors. The area of niobium hydride chemistry continues to be an extremely important area. It has been observed that hydrides, supported by bulky aryloxo ligands, catalyze homogenous hydrogenation of arenes. The field of hydride complexes of Ta is a prosperous area in organometallic chemistry. Recent progress has shown that electrophilic mono-and binuclear tantalum hydride complexes are capable of reducing CO and N2, whereas the alkyl/aryl complexes are important in organic and organometallic chemistry.