BINUCLEAR RUTHENIUM CLUSTERS WITH MU-2-ETA-2-SULFONATO LIGANDS - SYNTHESIS AND MOLECULAR-STRUCTURE OF RU2(CO)4[MU-2-ETA-2-OOS(O)TOL]2(PPH3)2

Dodecacarbonyltriruthenium reacts with sulphonic acids to give dinuclear ruthenium complexes containing mu2-eta2-sulphonato bridges. The triphenylphosphine derivatives Ru2(CO)4[mu2-eta2-OOS(O)R]2(PPh3)2 (1: R = CF3; 2: R = Me; 3: R = Et; 4: R = (+)-Camph; 5: R = Ph; 6: R = Tol) have been isolated and characterized: the molecular structure of 6 has been established by a single-crystal X-ray structure analysis. Compound 6 crystallizes in two different space groups: in the space group A2/n (a 17.602(2), b 16.659(2), c 20.5234(2) angstrom, beta 106.57(1)-degrees Z = 4) with crystallographic C2 symmetry, and in the space group P2(1)/n (a 17.506(1), b 15.539(1), c 37.889(4) angstrom, beta 93.84(1)-degrees, Z = 8) with two independent molecules (I and II) per asymmetric unit. The two ruthenium atoms are bridged by the two sulphonato ligands, the average Ru-Ru distance being 2.776(1) angstrom for the three conformers. The CO groups are trans with respect to the bridging ligands, giving rise to a sawhorse-like structure.