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

Microwave irradiation of a toluene solution of the diyne FcC(2)C(2)Ph and Ru-3(CO)(12) yields the [Ru(CO)(3)(eta(4)-ruthenole)] derivatives 1a-f, which differ in relative positions of the uncoordinated alkyne group. Upon treatment with Pt(PPh3)(2)C2H4, the ruthenoles 1a-c, containing a single free C equivalent to C unit at the a 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 equivalent to C unit at the alpha position, and If, having free C equivalent to C units at both alpha 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.