SYNTHESIS AND CRYSTAL-STRUCTURE OF [RU3PT(MU-PPH2)(MU-4-ETA-2-C=CBUT)(CO)7(DPPE)] (DPPE = PH2PCH2CH2PPH2), A BUTTERFLY CLUSTER CONTAINING AN UNUSUALLY BONDED ALKYNYL LIGAND - A MODEL FOR AN INTERMEDIATE MOLECULAR-GEOMETRY IN A CLUSTER LIGAND REARRANGEMENT

Reaction of [Ru3Pt(mu-H)(mu-4-eta-2-C = CBu(t)(CO)9(L2)] 1a (L2 = dppe) with Ph2PC = CPPh2 affords the butterfly cluster [Ru3Pt(mu-PPh2)(mu-4-eta-2-C = CBu(t)(CO)7(dppe)] 3; the metal skeleton and mu-4-eta-2 alkynyl coordination mode in 3 represent a likely model for a transition geometry in the interconversion of 1 and its vinylidene tautomer [Ru3Pt{mu-4-eta-2-C = C(H)Bu(t)}(CO)9(L2)] 2.