Reaction of a (Salen)ruthenium(VI) Nitrido Complex with Isocyanide

The treatment of [Ru-VI(N)(L)(MeOH)]PF6 (1) (L = N,N'-bis(salicylidene)-o-cyclohexyldiamine dianion) with 2 equiv of RNC (R = (a) Bu-t, (b) Cy) in CH2Cl2 affords a mixture of blue cis-beta-[Ru-III(NCNR)(L)(CNR)) (2) and green trans-[Ru-III(L)(CNR)(2)]PF6 (3) products. The reduction of 3 with a stoichiometric amount of Cp2Co in CH3CN gives red trans-[Ru-II(L)(CNR)(2)] (4). Refluxing 4 with 3 equiv of RNC in methanol in the presence of 5 equiv of NH4PF6 affords a yellow complex, mer-[Ru-II(eta(3)-HL)(CNR)(3)](PF6) (5), in which the ligand is in an eta(3)-coordination mode. These complexes are characterized by IR, UV-vis, ESI-MS, CV, magnetic measurements, and CHN elemental analysis. The structures of 2a, 3a, 4a, 4b, and 5a have been determined by X-ray crystallography.