Chiral modified electrodes. Part 2. Marcus behaviour and high enantioselectivity in the photoelectrochemistry at a polymeric [Ru(4-methyl-4'-vinyl-2,2'-bipyridine)3]2+electrode

Publication Type
Journal contribution
Authors
Felcmann, Ch.; Greiner, G.; Rau, H.; Wörner, M.
Year of publication
2000
Published in
Phys. Chem. Chem. Phys.
Band/Volume
2/15
ISBN / ISSN / eISSN
1463-9076
Page (from - to)
3491-3497
Abstract

Indium-tin-dioxide (ITO) and Pt electrodes can be modified with films of the photo- and redox-active polymer of [Ru(4-methyl-4'-vinyl-2,2'-bipyridine)3]2+ ([Ru(vbpy)3]2+). These modified electrodes show photocurrents when K3[Co(ox)3] is reduced in a photoelectrochem. reaction.These photocurrents are, inter alia, dependent on the potential applied to the electrode assembly. The photocurrent vs. voltage plots have maxima. Changing the potential means changing the driving force of the electrode reaction and the authors can interpret the max. plots by Marcus' theory for reactions in the normal and inverted region. For the study of a chem. reaction, electrodes with larger surfaces are necessary. In the photo-assisted redn. of K3[Co(ox)3] by a reticulated Ni-foam electrode modified by a chiral redox active polymer of [Ru(vbpy)3]2+ the authors found enantio-selectivity with .kappa.=k.LAMBDA./k.DELTA. of up to 12, one of the highest values of asymmetry reported for photochem. reactions. Modified electrodes, where the optically excited electron transferring species in the polymer is the chiral element, represent a new type of chiral inductor.

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