CYCLOMETALATION OF BIS(DIPHENYLPHOSPHINO)METHANE LIGANDS ON A BINUCLEAR RUTHENIUM(0) CARBONYL COMPLEX

The first example of simple orthometallation of a bis(diphenylphosphin o)methane ligand at a binuclear centre is reported. Both dppm ligands of the binuclear ruthenium(0) complex [Ru-2(CO)(5)(mu-dppm)(2)], 1, ar e orthometallated when the complex is heated in benzene solution to yi eld the unusual complex [Ru-2(CO)(4)(Ph(2)PCH(2)PPhC(6)H(4))(2)], 2. T he structure of 2 was determined crystallographically (monoclinic, P2( 1)/n, a = 21.349(4), b = 12.209(5), c = 22.457(5) Angstrom, beta = 104 .34(2)degrees, Z = 4, R, R(W) = 0.0658, 0.0561) and the unusual cyclom etallated complex was also characterized spectroscopically. The cyclom etallation occurs in such a way that each ligand gives rise to two fus ed five-membered rings, RuRuPCP and RuRuPCC, fused at the Ru-Ru and Ru -P bonds.