COMPLEXES OF THE PLATINUM METALS .43. N,N'-DIPHENYLAMIDINATO DERIVATIVES OF RUTHENIUM, OSMIUM AND IRIDIUM

N,A'-Diphenylamidines PhN=C(R)-NHPh (R = H, Me, Et or Ph) reacted with the precursors [MH,2-(CO)(PPh3)3], [MH(Cl)(CO)(PPh3)3] and [M(O2CCF3)2(CO)(PPh3)2].nMeOH (M = Ru, n = 0.75; or Os n = 0.33) in boiling benzens to afford the amidinato complexes [MH{PhNC(R)NPh}(CO)(PPh3)2], [MCl{PhNC(R)NPh}(CO)(PPh3)2] and (M(O2CCF3)(PhNC(R)NPh)(CO)(PPh3)2] respectively. The hydrides [MH{PhNC(R)NPh}(CO)(PPh3)2] have also been obtained by oxidative addition of amidines to [Ru(CO)3(PPh3)2] and by treatment of the precursors [MH(Cl)(CO)(PPh3)3] with amidines in the presence of an excess of base (NEt3). The trifluoroacetates [M(O2CCF3)2(CO)(PPh3)2].nMeOH reacted with amidines in the presence of NEt3 to afford the hydrides [MH{PhNC(R)NPh}(CO)(PPh3)2] (M = Ru, R = H; M = Os, R = H, Me, Et or Ph) or the bis(amidinato) complexes [M{PhNC(R)NPh}2(CO)(PPh3)] (M = Ru; R = Me, Et or Ph). Reactions of thedichlorides [MCl2(PPh3)3] with amidinesand base (NEt3) in boiling toluene containing traces of alcohol were accompanied by a carbonyl-abstraction reaction leading to formation of [MH(PhNC(R)NPh)(CO)(PPh3)2] and/or [MCl{PhNC(R)NPh}(CO)(PPh3)2]. The hydrides [MH{PhNC(R)NPh}(CO)(PPh3)2] are also obtained when [RuH2(PPh3)4] or [OsH4(PPh3)3] reacts with amidines in boiling toluene (containing a trace of alcohol) or in 2-methoxyethanol. The carbonyl abstractions are remarkable in that they have no parallel in the corresponding reactions involving the related triazenide (PhNNNPh-) and carboxylate (RCO2-) ligands even when neat alcohols are used as solvents. Reactions of mer-[IrH3(PPh3)3], [IrHCl2(PPh3)3]-NEt3 and [IrHCl2(PPh3)3] with amidines in boiling benzene or toluene afforded [IrH2{PhNC(R)NPh}(PPh3)2], [IrH(Cl){PhNC(R)NPh}(PPh3)3] and [IrCl2{PhNC(Ph)NPh}(PPh3)2] respectively.