N,N′-diphenylthioureido complexes of ruthenium, osmium and iridium

N,N'-Diphenylthiourea reacts with [RuHCl(CO)(PPh3)(3)] and [Ru(H)(2)(CO)(PPh3)(3)] in refluxing benzene to afford the N,N'-diphenylthioureido complexes [RuCl{PhNC(NHPh)S}(CO)(PPh3)(2)] and [RuH{PhNC(NHPh)S}(CO)(PPh3)(2)], respectively. Under more forcing conditions in refluxing toluene the precursors [MHCl(CO)(PPh3)(3)] (M = Ru or Os) and [Os(H)(2)(CO)(PPh3)(3)] afford the thioureido complexes [M{PhNC(NHPh)S}(2)(CO)(PPh3)] and the known N-phenylthioformamidato complex [OsH{PhNC(H)S}(CO)(PPh3)(2)], respectively. The reaction of [RuCl2(PPh3)(3)] with N,N'-diphenylthiourea and triethylamine in boiling toluene yields [Ru{PhNC(NHPh)S}(2)(PPh3)(2)]. Finally the reaction of mer-[Ir(H)(3)(PPh3)(3)] with N,N'-diphenylthiourea in boiling toluene affords [Ir(H)(2){PhNC(NHPh)S}(PPh3)(2)]. Spectroscopic evidence indicates that the N,N'-diphenylthioureido anions are bound as N,S chelates, and this coordination mode has been confirmed for [Ru{PhNC(NHPh)S}(2)(CO)(PPh3)] by an X-ray crystal structure determination. Trends in exocyclic C-NR2 bond lengths for related guanidinato, thioureido and dithiocarbamato complexes are reported. (C) 2000 Elsevier Science S.A. All rights reserved.