Mori, A; Suzuki, T; Sunatsuki, Y; Kojima, M; Nakajima, K
Reactions of a ruthenium(II) complex containing quinoline-2-carbaldehyde (pyridine-2-carbonyl)hydrazone (HL), trans(P,P)-[RuCl2(PPh3)(2)(HL)] (1), and 3d-metal(II) chlorides resulted in heterodimetallic complexes, [RuCl2(PPh3)(2)-(mu-L)MCl2] (2M, M = Mn, Fe, Co, Ni, Cu, and Zn), in which the deprotonated hydrazonate (L-) bridged two metal ions in the mu-1(Ru)kappa N-2,O:2(M)kappa N-3',N '',N''' mode. The coordination bond lengths around the Ru and M centers suggested that the oxidation states in the complexes 2M could be assigned as Ru-III and M-II; this was also supported by magnetic, electrochemical, and spectroscopic measurements. In addition, oxidation of complex 1 by (NH4)(2)[Ce(NO3)(6)] gave the corresponding mononuclear Ru-III complex with the deprotonated hydrazonate, trans(P,P)-[RuCl2(PPh3)(2)(L)] (3). It is suggested that oxidation of the Ru center lead to the concerted deprotonation from the hydrazone ligand. Addition of excess HClO4 to complex 3 gave a doubly protonated Ru-III complex, 4(ClO4)(2); in this complex the hydrazonate moiety was not protonated, but both the quinolyl and pyridyl N atoms were protonated. Complexes 3 and 4(2+) could be interconverted by the addition of acid or base without changing the oxidation state of the Ru center.