Mononuclear and dinuclear iridium and heterodinuclear iridium–rhodium complexes derived from 1,4-C6H4(CCSiMe3)2 as precursor

The labile iridium(I) precursor trans-[IrCl(C8H14)(PiPr3)2] (2), prepared in situ from [IrCl(C8H14)2]2 (1) and PiPr3, reacted with equimolar amounts of 1,4-C6H4(CCSiMe3)2 (3) at 60 °C to give the mononuclear vinylidene complex trans-[IrCl(CC(SiMe3)C6H4CCSiMe3)(PiPr3)2] (4). From 2 and 3 in the molar ratio of 2:1, the dinuclear compound trans,trans-[(PiPr3)2ClIr(CC(SiMe3)C6H4C(SiMe3)C)IrCl(PiPr3)2] (5) was obtained. Reaction of 4 with [RhCl(PiPr3)2]2 (6) at room temperature afforded the heterodinuclear alkyne(vinylidene) complex trans,trans-[(PiPr3)2ClIr(CC(SiMe3)C6H4CCSiMe3)RhCl(PiPr3)2] (7), which on heating at 45 °C was converted to the bis(vinylidene) isomer trans,trans-[(PiPr3)2ClIr(CC(SiMe3)C6H4C(SiMe3)C)RhCl(PiPr3)2] (8).