Interaction of some Lewis acids with the oxide-bridge of (mu-oxo)di( mu-acetato)diruthenium (III, III) complexes and its electrochemical consequence

Interaction of some Lewis acids to the oxide bridge of [Ru-2(mu-O)(mu-CH3CO O)(2)(2,2'-bipyridine)(2)(L)(2)](2+) (L = 1-methylimidazole (1), pyridine ( 2)) and its electrochemical consequence were examined. The complexes themse lves show reversible Ru-2(III, III / III, IV) and Ru-2(II, III / III, III) processes and an irreversible Ru-2(II, II / II, III) process in acetonitril e (0.1 M n-Bu4NPF6) at 0.78 (0.95) (E-1/2), -0.55 (-0.39) (E-1/2) and -1.16 (-1.09) V (Epa) vs. Ag/AgCl, respectively, for 1 (data in parentheses are for 2). On addition of BF3 and Al3+, all the redox potentials shift to the positive direction. Addition of Li+ and Na+ causes the shift of only the mo st negative E-1/2 to overlap with the middle one to show an apparent one-st ep two-electron process Ru-2(II, II / III, III) at -0.55 V. BF3 and Al3+ in teract with the oxide bridge of the complexes at the oxidation states Ru-2( III, III), (II, III) and (II, II) while the alkali metal ions do only at th e Ru-2(II, II) state.