Preparation of cobalt polyporphine and its catalytic properties in oxygen electroreduction

Abstract

International audienceA new member of the polyporphine series-cobalt polyporphine of type I (pCoP-I)-was prepared from the starting magnesium polyporphine of type I (pMgP-I) by ion exchange, i.e. by sequential processing of the pMgP-I polymer film on the electrode surface with solutions of trifluoroacetic acid (forming metalfree polyporphine of type I, pH(2)P-I) and cobalt(II) acetate in organic solvents. The completeness of each stage of ion exchange can be judged from the change in the electrochemical and spectral characteristics of the obtained polymer films of unsubstituted porphine (?H2P-I) and cobalt porphine (pCoP-I) of type I. Oxidative transformation of this polyporphine pCoP-I was performed, which led to the formation of additional bonds between the neighboring porphine units in the polymer film (transition of polymer of type I into polymer of type II, pCoP-II). The behavior of the polymer films of cobalt polyporphine of types I and II in oxygen electroreduction was studied. The films showed catalytic activity in this process

A glassy carbon electrode modified by a triply-fused-like Co(ii) polyporphine and its ability for sulphite oxidation and detection

“…In our previous contribution in this field 34,39 we demonstrated that the magnesium(II) centers in pMgP-I could be exchanged with a cobalt(II) ion thus providing an easy, quick and repeatable way to obtain a cobalt(II) polyporphine of type I pCoP-I. Since this time we experienced that this material was unstable in aqueous matrix over potential cycling although it was designed for a use in electrochemical sensing in this medium.…”

Electrochemical quartz crystal microbalance study of magnesium porphine electropolymerization process

“…1), represents a homopolymer possessing original optical and electric properties [28]. It also serves as the starting compound for synthesis of the Mg polyporphine of type II (pMgP-II) [29] as well as freebase polyporphines and polymetalloporphines of various metals [30][31][32][33][34]. These reasons have led to a detailed study of the mechanism of this polymer (pMgP-I) deposition since it is the stage which largely determines characteristics of all subsequent poly(metallo)porphines.…”