Dinuclear ruthenium(II) bipyridine complexes having non-symmetric α,α′-diimine based neutral bridging ligands.

摘要: Abstract A group of three dinuclear ruthenium(II) complexes the type [(bpy)2RuII(L)RuII(bpy)2](ClO4)4·2H2O, 1a–1c [bpy=2,2′-bipyridine, L=bridging ligand, NpC5H4CH=Ni–(R)–Ni=CHC5H4Np; R=none, 1a; R=–C6H4–, 1b; R=–CH2–C6H4–CH2–, 1c] have been synthesized and characterized. The are essentially diamagnetic behave as 1:4 electrolytes in acetonitrile solution. mass molecular ion for complex 1a geometry 1 solution assessed by fast atom bombardment (FAB) spectrometry 1H/13C NMR spectroscopy, respectively. Complexes display metal-to-ligand charge-transfer (MLCT) transitions visible region, where lowest energy MLCT transition is considered to be a dπ(RuII)→π*(L) transition. other two higher believed dπ(RuII)→π*(bpy) transitions. Highly intense ligand-based π→π* observed UV region. In solvent, show one quasi-reversible two-electron oxidation process near 1.5 V vs. Ag/AgCl, due simultaneous one-electron oxidations [ruthenium (III)⇌ruthenium(II)] both ruthenium centers multiple reductions range −0.5–−2.7 successive coordinated bridging L, well bipyridine. chemically electrochemically generated oxidized trivalent congeners unstable at room temperature.