REACTIONS OF THE TRINUCLEAR CLUSTER (MU(2)-H)RU-3(CO)(9)(MU(3),ETA(2)-SCNHPHNPH) - SYNTHESIS AND MOLECULAR-STRUCTURE OF PH(3))(MU(2),ETA(2)-C6H5)-(MU(2)-PPH(2))(MU(3)-S), A COMPLEX CONTAINING A PHENYL LIGAND WITH A RARE SIGMA,PI-COORDINATION MODE

Reactions of the previously isolated trinuclear cluster (mu(2)-H)Ru-3( CO)(9)(mu(3) eta(2)-SCNHPhNPh) (1) with excess diphenylthiourea result in cluster fragmentation to produce the mononuclear complex Ru(CO)(2) (eta(2)-SCNHPhNPh)(2) (2) containing two bidentate diphenylthioureato ligands, Room-temperature reactions of 1 with 1 or 2 equiv of tripheny lphosphine result in substitution of one or two carbonyl groups, respe ctively, to give the clusters (2)-H)Ru-3(CO)(8)-(PPh(3))(mu(3),eta(2)- SCNHPhNPh) (3) and )-H)Ru-3(CO)(7)(PPh(3))(2)(mu(3),eta(2)-SCNHPhNPh) (4). An X-ray crystal structure analysis shows 3 to represent a monosu bstituted derivative of 1 with the PPh(3) ligand occupying an equatori al position on one of the two bridgehead ruthenium atoms; the crystal belongs to the triclinic space group <P(1)over bar>; Z = 2, a = 10.014 (2) Angstrom, b = 14.449(4) Angstrom, c = 14.573(4) Angstrom, alpha = 100.38(2)degrees, beta = 98.70(2)degrees, and gamma = 107.20(2)degrees . Thermolysis of either 1 in the presence of 2 equiv of PPh(3), or of 4 alone, gives the sulfur-capped, trinuclear cluster (PPh(3))(mu(2),et a(2)-C6H5)(mu(2)-PPh(2))(mu(3)-S) (5). X-ray structural analysis of 5 shows a diphenylphosphido bridge and a phenyl bridge resulting from P- C bond activation of a PPh(3) group and C-H activation of the aryl gro up; crystals of 5 are monoclinic, space group P2(1)/n; Z = 4, a 10.824 (1) Angstrom, b = 19.193(5) Angstrom, c = 20.953(2) Angstrom, and beta = 97.44(1)degrees. Diphenylphosphinoethane (dppe) is found to replace two carbonyl ligands on two adjacent Ru atoms to give the cluster (mu (2)-H)Ru-3(CO)(7)(Ph(2)PCH(2)CH(2)PPh(2))- (mu(3),eta(2)-SCNHPhNPh) (6 ) whose X-ray structural analysis shows a dppe ligand bound cis to the mu(2)-S of the diphenylthioureato ligand and cis to the mu(2)-H ligan d. Crystals of 6 are monoclinic, space group P2(1)/n; Z = 4, a17.667(7 ) Angstrom, b = 17.681(5) Angstrom, c 18.049(4) Angstrom, and beta = 1 08.06(2)degrees.