Electrochemically formed fullerene-based polymers
|Krzysztof Winkler 1, Wlodzimierz Kutner 2, Alan L. Balch 3|
1. University of Białystok, Institute of Chemistry, Hurtowa 1, Białystok 15-399, Poland
New materials based on electrochemically active polymers are continuously being developed for numerous applications. They can be used in electrotechnology, electrocatalysis and electroanalysis. From this point of view, fullerene-based polymers are very attractive. Up to six, reversible, one-electron steps are observed for the reduction of C60 in solution. Fullerene cages incorporated into polymeric structures are expected to retain this sort of electrochemical activity.
Electrochemical methods were also used for forming fullerene-based polymers and their immobilization on the electrode surfaces. These techniques allow control the amount of polymer deposited, its morphology, and its oxidation state. Electrochemically produced polymeric systems can be divided into four groups: (i) "charm bracelet" polymers formed from the electrochemically active fullerene derivatives, (ii) ionically induced polymers, (iii) fullerene epoxide based polymers, and (iv) "pearl necklace" co-polymers of fullerenes and transition metal complexes. In this presentation, special emphasis is placed on the electrochemically formed fullerene epoxide based polymers and polymers of fullerenes and transition metal complexes.
Polymeric films are formed during electroreduction of epoxide C60O. It has been postulated that the electrochemically formed C60O2- anion initiates the polymerization process. In the polymeric network, C60 cages may be connected through covalent C-O-C linkages although direct C-C linkages are also likely to be involved. Related films are readily prepared by the reduction of C60 and C70 in the presence of limited amounts of dioxygen in a toluene/acetonitrile mixture.
A two-component electroreductive process that involves the reduction of C60 (or a C60 derivative) in the presence of transition metal complexes of Pt, Pd, Ir, and Rh has been also developed. The fullerene/transition metal films that result are particularly interesting. In these systems, the polymeric network is believed to be formed through covalent bonding between transition metal atoms (or complexes) and fullerenes.
Presentation: Keynote lecture at SMCBS'2005 Workshop, by Krzysztof Winkler
See On-line Journal of SMCBS'2005 Workshop
Submitted: 2005-07-27 07:43 Revised: 2009-06-07 00:44