Synthesis of Novel Allene-Coordinated, Phosphido-Bridged Ru2Pt Clusters Involving Enyne to Allene Transformation

Microwave irradiation of a toluene solution of the diyne FcC2C2Ph and Ru3(CO)12 yields the [Ru­(CO)3(η4-ruthenole)] derivatives 1a–f, which differ in relative positions of the uncoordinated alkyne group. Upon treatment with Pt­(PPh3)2C2H4, the ruthenoles 1a–c, containing a single free CC unit at the α position with respect to the ring Ru metal, yield the novel allene-coordinated, phosphido-bridged Ru2Pt clusters 3a–c along with their phosphine-substituted derivatives 4a–c. Under similar reaction conditions, isomers 1d,e, which are devoid of any free CC unit at the α position, and 1f, having free CC units at both α positions, form only their phosphine-substituted derivatives 4d–f. The formation of Ru2Pt clusters from ruthenole complexes involves cleavage of the P–C bond of the phosphine and migration of the resulting phenyl group onto the free alkyne, which leads to enyne to allene transformation.