Benzene-1,2-dithiolate-induced assembly of reactive iridium fragments into tetranuclear octahydride complexes

The tetrametallic compound [Ir4(μ-1,2-S2C6H4)2(μ-H)2H6(PiPr3)4(NCMe)] (1) has been obtained by treatment of the reactive cationic complex [IrH2(PiPr3)(NCMe)3]BF4 with the benzene-1,2-dithiolate anion. In the solid state, this tetrametallic compound exhibits an irregular nearly planar metal skeleton with the two dithiolate anions bridging the four metal centres from the same side of the tetrametallic plane. Even though all iridium atoms coordinate one PiPr3 ligand, two bridging S atoms and, at least, two hydrides, they show different electronic and coordination environments. This unusual structure is maintained in solution, even after substitution of the labile acetonitrile ligand by other Lewis bases such as ethylene or carbon monoxide.