High Nuclearity Heterometallic Gold(I)-Containing Derivatives from Manganese(I) and Ruthenium(II) dppm Complexes via Diphosphinomethanide Intermediates

Abstract

The cationic complexes trans-[RuCl(L)(dppm)2]+ (1a, L = CO; 1b, L = CNtBu; 1c, L = CNPh), trans-[Ru(CNR)2(dppm)2]2+ (1d, R = tBu; 1e, R = Ph), and trans-[Mn(CO)2(dppm)2]+ (1f) are selectively deprotonated with KOH or NaMeO affording the mixed ligand dppm/dppm-H complexes (dppm-H = [(PPh2)2CH]-) trans-[RuCl(L)(dppm)(dppm-H)] (2a−c), trans-[Ru(CNR)2(dppm)(dppm-H)]+ (2d,e), and trans-[Mn(CO)2(dppm)(dppm-H)] (2f), respectively. Under more forcing conditions, 2d and 2e undergo a second deprotonation reaction to give trans-[Ru(CNR)2(dppm-H)2] (3d,e). The treatment of 1f with [AuCl(PPh3)] in the adequate stoichiometric ratio, in the presence of an excess of KOH, affords the heterometallic complexes trans-[Mn(CO)2(dppm){(PPh2)2CH(AuPPh3)}]+ (4f), trans-[Mn(CO)2{(PPh2)2CH(AuPPh3)}2]+ (5f), trans-[Mn(CO)2{(PPh2)2CH(AuPPh3)}{(PPh2)2C(AuPPh3)2}]+ (6f), and trans-[Mn(CO)2{(PPh2)2C(AuPPh3)2}2]+ (7f) as a result of the stepwise double metalation of the two dppm ligands. 4f is more conveniently prepared by reaction of 2f with an excess of [AuCl(PPh3)], although a good purification of the complex is not achieved. For 5f, two isomers are present, in the same proportion, corresponding to the mutually syn or anti disposition of the two Au(PPh3) fragments. By contrast, in the treatment of the ruthenium derivatives 1d and 1e with [AuCl(PPh3)] in the presence of KOH, the products of partial metalation of the dppm ligands were not obtained and only the fully metalated pentametallic species trans-[Ru(CNR)2{(PPh2)2C(AuPPh3)2}2]2+ (7d and 7e) were isolated. For 2a and 7e, an X-ray diffraction study was undertaken.