Synthesis and Characterization of Ru2(DMBA)4X2 (X = CN, N3, N(CN)2, I): Controlling Structural, Redox, and Magnetic Properties with Axial Ligands

Metathesis reactions between Ru2(DMBA)4Cl2 (DMBA = N,Nʹ-dimethylbenzamidinate) and MX (M = Na and K) yielded bis-adduct derivatives Ru2(DMBA)4X2 (X = CN (1), N3 (2), N(CN)2 (3)). Metathesis reactions between Ru2(DMBA)4(NO3)2 and KI resulted in Ru2 (DMBA)4I2 (4). Compound 1 is diamagnetic, while compounds 2-4 are paramagnetic (S = 1). Both compounds 1 and 2 undergo two reversible one-electron processes, an oxidation and a reduction, while compound 3 features a quasireversible reduction. Single-crystal X-ray diffraction studies revealed that the Ru-Ru bond lengths are 2.4508(9), 2.3166(7), 2.304[1], and 2.328(1) (angstrom) for compounds 1-4, respectively. Structural and electrochemical data clearly indicate that the axial ligands impart a significant influence on the electronic structures of diruthenium species.