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.