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

• Published in: Journal of organometallic chemistry Vol. 637; pp. 390 - 397
• Main Authors: Ding, Li, Ma, Kuangbiao, Bolte, Michael, Fabrizi de Biani, Fabrizia, Zanello, Piero, Wagner, Matthias
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 03.12.2001
• Subjects: 2,2′-Bipyridylboronium cations; Cyclic voltammetry; Ferrocene; Oligonuclear complexes; X-ray crystal structure analysis; Cyclic voltammetry; X-ray crystal structure analysis; 2,2′-Bipyridylboronium cations; Oligonuclear complexes; Ferrocene
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/S0022-328X(01)00942-1

A high-yield synthesis and the X-ray crystal structure analysis of the dinuclear complex [FcB(bipy)OC 6H 4O(bipy)BFc](PF 6) 2, 6(PF 6) 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(PF 6) 2 exhibits a ferrocene-centered two-electron oxidation wave and two separate bipyridylboronium-centered two-electron reduction steps. No oxidation of the hydroquinone spacer takes place in the solvent window. 6(PF 6) 2 is thus able to accept or deliver up to six electrons. Attempts to connect two [FcB(bipy)] fragments using glycol rather than hydroquinone as the bridging element gave the mononuclear complex [FcB(bipy)O(CH 2) 2OH]PF 6 only. A similar reaction scheme that was applied for the generation of [FcB(bipy)O(CH 2) 2OH]PF 6 was employed to synthesize the diol {1,1′-[HO(CH 2) 2OB(bipy)]2fc}(PF 6) 2; fc=[(C 5H 4) 2Fe]. This compound is able to store up to five electrons and may find use as a monomer for the generation of cationic, redox-active polyesters and polyurethanes. The synthesis and X-ray crystal structure analysis of the three-step redox system 6(PF 6) 2 is described. The compound, which consists of three different redox-active fragments (i.e. ferrocene, bipyridylboronium cations, hydroquinone) can accept or deliver up to six electrons. Related ferrocene-based diols have been developed as monomers for the generation of cationic, redox-active polyesters and polyurethanes.