PENTAMETHYLCYCLOPENTADIENYL IRIDIUM COMPLEXES CONTAINING CHALCOGENIDOLIGANDS - REACTIONS OF CP-ASTERISK-IR(CO)(2) WITH ELEMENTAL SULFUR AND SELENIUM

Photolysis or thermolysis of CpIr(CO)(2) (1) in the presence of exces s sulfur (S-8) gives CpIr(CO)(S-4) (2a) which is further S decarbonyl ated to [CpIr(mu-S-4)](2) (4a). The analogous reaction of 1 with exce ss selenium leads to Cp(2)Ir,(mu-Se)(mu-Se-4) (6b). In the case of li mited chalcogen supply, the products are [CpIr(CO)(mu-E](2) [E = S (3 a), Se 3 b)] and [CpIr(mu-E)](4) [E = S (5a), Se (5b)]. A stepwise fo rmation of the pseudocubane clusters 5a,b from dinuclear precursors is assumed. The solid-state structure of 2a has been determined by X-ray crystallography.