Multistep redox properties of 2,2 '-bipyridylboronium substituted ferrocenes

A high-yield synthesis and the X-ray crystal structure analysis of the dinu clear complex [FcB(bipy)OC6H4O(bipy)BFc](PF6)(2), 6(PF6)(2), which consists of two ferrocenyl moieties, two 2,2'-bipyridylboronium substituents and a hydroquinone linker, is described. The compound is perfectly stable toward air and moisture. 6(PF6)(2) exhibits a ferrocene-centered two-electron oxid ation wave and two separate bipyridylboronium-centered two-electron reducti on steps. No oxidation of the hydroquinone spacer takes place in the solven t window. 6(PF6)(2) is thus able to accept or deliver up to six electrons. Attempts to connect two [FcB(bipy)] fragments using glycol rather than hydr oquinone as the bridging element gave the mononuclear complex [FcB(bipy)O(C H2)(2)OH]PF6 only. A similar reaction scheme that was applied for the gener ation of [FcB(bipy)O(CH2)(2)OH]PF6 was employed to synthesize the diol {1,1 '-[HO(CH2)(2)OB(bipy)]2fc}(PF6)(2); fc = [(C5H4)(2)Fe]. This compound is ab le to store up to five electrons and may find use as a monomer for the gene ration of cationic, redox-active polyesters and polyurethanes. (C) 2001 Els evier Science B.V. All rights reserved.