CYCLOPENTADIENYL-RUTHENIUM AND PENTAMETHY LCYCLOPENTADIENYL-RUTHENIUMCOMPLEXES WITH CARBOXYLATE, VINYL-ESTER AND CARBENE LIGANDS

Monomeric carboxylatoruthenium(II) complexes [C5R5Ru(eta(2)-O2CR')(PPh 3)] (R = H, Me; R' = Me, Bu-t, CF3) were prepared by ligand displaceme nt from [(C5R5)Ru(eta(3)-2-MeC3H4)(PPh3)] and R'CO2H. From a similar r oute, the tosylato and pentachlorphenolato derivatives [C5H5Ru{O2SO(p- C6H4Me)}(PPh3)](n) and [C5H5Ru(eta(2)-OC6Cl5)(PPh3)] were obtained. On treatment with PhNH2, CO, PPh3 and O-2, they reacted to give the comp lexes [C5H5Ru{O2SO(p-C6H4Me)}(L)(PPh3)] and [C5H5Ru(OC6Cl5(CO)(PPh3)] respectively. The reaction of [C5R5Ru(eta(2)-O2CRt)(PPh3)] (R' = Me, B u-t) with terminal alkynes HC=CR (R = CO2Me, Ph) yielded the vinyleste rruthenium(II) compounds [C5H5Ru(kappa(2)(C,O)-C(=CHR)OC(R')=O}(PPh3)] for which a resonance structure involving a carboxylato(vinylidene) s pecies is postulated. The carbene half-sandwich type complexes [C5H5Ru Cl(=CRR')(PPh3)] (R and R' = C6H4X) were prepared in two steps from [C 5H5Ru(eta(2)-O2CMe)(PPh3)], N2CRR' and either Al2O3/Cl- or Et3NHCl. Th e molecular structure of [C5Me5Ru(eta(2)-(O2CBu)-Bu-t)(PPh3)] and [C5H 5RuCl(=CPh2)(PPh3)] have been determined by X-ray single-crystal struc tural investigations.