Coupling of (Salen)ruthenium(VI) Nitrides

Reaction of [RuVI(N)(L1)(MeOH)]+ (L1 ) N,N′-bis(salicylidene)-o-cyclohexylenediamine dianion) with excess pyridine in CH3CN produces [Ru(L)(py)2] and N2. The proposed mechanism involves initial equilibrium formation of [RuVI(N)(L1)(py)]+, which undergoes rapid N · · · N coupling to produce [(py)(L1)RuIIINtN-RuIII(L1)(py)]2+; this is followed by pyridine substituion to give the final product. This ligand-induced N · · · N coupling of RuVItN is utilized in the preparation of a series of new ruthenium(III) salen complexes, [Ru(L)(X)2] ( (L ) salen ligand; X ) H2O, 1-MeIm, py, Me2SO, PhNH2, BuNH2, Clor CN-). The structures of [Ru(L)(NH2Ph)2](PF6) (6), K[Ru(L)(CN)2] (9), [Ru(L)(NCCH3)2][Au(CN)2] (11) (L2 ) N,N′-bis(salicylidene)-o-phenylenediamine dianion) and [NBu4][Ru(L)Cl2] (12) (L3 ) N,N′-bis(salicylidene)ethylenediamine dianion) have been determined by X-ray crystallography.