Chapter 2: Chalcogenocarbonyl and Chalcogenonitrosyl Metal Complexes

Compared to the well-known chemistry of carbonyl (CO) and thiocarbonyl (CS) as well as nitrosyl (NO) complexes of transition-metals, the chemistry of their heavier chalcogen isologues, i.e., selenocarbonyl (CSe) and tellurocarbonyl (CTe) as well as thionitrosyl (NS) and selenonitrosyl (NSe) complexes, still remain in the early stages of development. The limited availability of these heavier carbonyl and nitrosyl compounds has hampered our understanding of a series of chalcogenocarbonyl (CE; E = O, S, Se, Te) and chalcogenonitrosyl (NE; E = O, S, Se, Te) ligands. In this chapter, a comparative analysis of the chemistry of transition-metal complexes that contains a CE and an NE ligand is described with particular attention to synthetic methods and structural aspects.