Dinuclear complexes of rhodium(I) containing diisocyanide ligands and some of their phosphine derivatives

Abstract

A series of organic diisocyanides [(1,3-diisocyanopropane, 1,4-diisocyanobutane, 1,5-diisocyanopentane, 1,6-diisocyanohexane, 1,3-bis(isocyanomethyl)benzene and 1,4-bis(isocyanomethyl)cyclohexane)] was found to rapidly react with [RhCl(CO) 2] 2 or [RhCl(C 8H 12)] 2 to give the photosensitive complexes [Rh 2(diisocyanide) 4] 2+ (1–6). Reaction between 1,8-diisocyanooctane and [RhCl(C 8H 12)] 2 produces the monomeric cation [Rh(1,8-diisocyanooctane) 2] +. Photochemical solvolysis reactions of complexes 1–2 are examined. Reaction of 1–7 with bis(disphenylphosphino)methane (DPM) displaces two diisocyanide ligands to give trans-[Rh 2(diisocyanide) 2(DPM) 2] 2+ (8–14), which may also be obtained from the reaction of the diisocyanide and trans-[RhCl(CO)(DPM)] 2. Similarly, [Rh 2(diisocyanide) 2(PPh 3) 4] 2+ (15–19) may be prepared from reaction between [Rh 2(diisocyanide) 4] 2+ and triphenylphosphine or from the reaction of trans-[RhCl(CO)(PPh 3) 2] or [RhCl(PPh 3) 3] with the diisocyanide ligand. Complex 7 also reacts with triphenylphosphine and bis(diphenylphosphino)ethane(diphos) producing the complexes cis-[Rh(1,8-diisocyanooctane)(PPh 3) 2] + (20) and cis-[Rh(1,8-diisocyanooctane)(diphos)] + (21), respectively.