Tetrametallic clusters (Ir2Rh2) through an ancillary ortho-carborane-1,2-dichalcogenolato ligands

The tetrametallic cluster complexes{Cp*Ir[E2C2(B10H9)]}Rh-2(cod){Cp*Ir[E2C2(B10H10)]} (E = S (3a); Se (3b)) have been synthesized by reactions of the 16-electron half-sandwich iridium complexes [Cp*Ir{E2C2(B10H10)}] [Cp*= eta(5)-C5Me5, E = S (1a), Se (1b)] with [Rh(cod)(mu-OEt)(2)] at room temperature in toluene solution. In the solid state, this tetrametallic cluster exhibits an irregular nearly planar metal skeleton with the two carborane dichalcogenolato ligands bridging the four metal centers from both sides of the tetrametallic plane. Even though all metal atoms coordinate bridging chalcogen atoms, they show different electronic and coordination environments. The molecular structures of 3a and 3b have been determined by X-ray crystallography.