Synthesis and tuning of chemical properties by protonation/deprotonation of novel dinuclear ruthenium complexes containing 2,6,2 ',6 '-tetra(4,5-dimethylbenzimidazol-2-yl)-4,4 '-bipyridine

A novel dinuclear ruthenium complex, [(tpy)Ru(tmbimbpyH(4))Ru(tpy)] (ClO4)( 4), has been synthesized to introduce a new proton-induced molecular switch ing system, where tpy = 2,2':6',2 "-terpyridine and tmbimbpyH(4) = 2,6,2',6 '-tetra( 4,5-dimethylbenzimidazol-2-yl)-4,4'-bipyridine. Both fully protona ted and deprotonated forms of the dinuclear Ru complex were isolated and th e forms were interchangeable by the addition of acid or base. A longer wave length shift and a negative oxidation potential shift were observed when th e protonated Ru complex was fully deprotonated. (C) 2000 Elsevier Science S .A. All rights reserved.