SYNTHESIS OF TRIRUTHENIUM-RHODIUM TETRANUCLEAR CLUSTERS DERIVED FROM [RU3H3(CO)9(MU-3-COME)] - CRYSTAL-STRUCTURE OF [N(PPH3)2][RU3RHH2(CO)11(PPH3)] 0.6C5H12

Reaction of K[Ru3H2(CO)9(mu-3-COMe)] with [Rh(CO)3(PPh3)2][PF6] affords [Ru3H2(CO)9(mu-3-COMe)-{Rh(CO)2(PPh3)}] 3 in 80% yield, with [Ru3H(CO)9(PPh3)(mu-COMe)], [Ru3H(CO)8(PPh3)2(mu-COMe)] and [Ru3RhH2(CO)8(PPh3)3(mu-COMe)] as minor products; [Ru3RhH2(CO)9(PPh3)2(mu-COMe)] 8 was isolated from the corresponding reaction with [Rh(CO)(PPh3)2Cl] and exists as five interconverting isomers in solution. At room temperature 3 loses one CO group to form the tetrahedral cluster [Ru3RhH2(CO)10(PPh3)(mu-COMe)] 7. This consists of two isomers in solution, with the major one being the molecular structure observed in the crystal. On reaction with K[BHBu(s)3], complex 7 undergoes a demethylation reaction to form [N(PPh3)2][Ru3RhH2(CO)11(PPh3)] 9. A single-crystal X-ray diffraction study of [N(PPh3)2][Ru3RhH2(CO)11(PPh3)].0.6C5H12 was carried out: triclinic, space group P1 (no. 1), a = 12.244(2), b = 13.453(3), c = 11.926(3) angstrom, alpha = 111.40(2), beta = 101.30(2), gamma = 70.02(1)-degrees, Z = 1, R = 0.053 from 4349 observations [F > 3-sigma(F)]. This showed a structure derived from [Rh4(CO)12], with an apical Ru(CO)2(PPh3) unit, and the Rh atom in the basal plane. The two hydrides were not located directly, but are considered to bridge apical-basal Ru-Ru edges.