Preparation of viologen polymers with carbon chain spacers and their application to the electron-transfer reaction in heterophases

Viologen polymers (PV2+) with carbon chain spacers were prepared by the pol ymeric reaction with poly(4-vinyl pyridine). These polymers were used as an electron-transfer catalyst (ETC) for the reduction of azobenzene, either i n a Zn-PV2+ system (reductant: Zn, in CH3CN/ H2O) or in a Na2S2O4-PV2+ syst em (reductant: Na2S2O4, in CH2Cl2/H2O). It was found that viologen polymers had the ability to mediate the reduction of azobenzene and the length of s pacers linking viologen groups to polymeric chains also affected the electr on-transfer catalytic reactions. (C) 1999 John Wiley & Sons, Ltd.