REACTIONS OF RU-3(MU-DPPM)(CO)(10) WITH UNSATURATED-HYDROCARBONS CYCLOOCTA-1,3,5,7-TETRAENE - X-RAY STRUCTURES OF RU-3(MU-DPPM)(MU-C8H8)(CO)(6), RU-3(MU(3)-PPHCH(2)PPH(2))(MU(3)-C8H8)(PH)(CO)(5), 3(MU(3)-PPHCH(2)PPH(C6H4))(MU-C8H8)(MU-CO)(CO)(4), AND H)(MU(3)-PPH(2)CHPPH(C6H4))(MU-C8H9)(MU-CO)(CO)(4)

Reactions between Ru-3(mu-dppm)(CO)(10) and cycloocta-1,3,5,7-tetraene (cot) in refluxing thf afford the four complexes Ru-3(mu-dppm)(mu-C8H 8)(CO)(6) (2), Ru-3(mu(3)-PPhCH(2)PPh(2))(mu(3)-C8H8)(Ph)(CO)(5) (3), -3{mu(3)-PPhCH(2)PPh(C6H4)}(mu-C8H8)(mu-CO)(CO)(4) (4) and H){mu(3)-PP h(2)CHPPh(C6H4)}(mu-C8H9)(mu-CO)(CO)(4) (5) which have been structural ly characterised by means of X-ray crystallography. Complex 3 is the f irst example of an Ru-3 cluster containing a cot ligand capping the Ru -3 face. In 2 and 4, the cot ligand is found bridging an Ru-Ru edge; i n 2, only one Ru of this edge is bonded to a P atom. In 3, a P-C bond of the dppm ligand has oxidatively added to one Ru atom to give an unu sual example of a cluster-bonded sigma-phenyl group. Complex 5 contain s a C8H9 ligand and dppm unusually dimetallated at the methylene carbo n and at a phenyl group.