INVESTIGATION OF ELECTROCHEMICAL REVERSIBILITY AND REDOX-ACTIVE POLYPYRROLE FILM FORMATION OF AMIDE FERROCENE-PYRROLE DERIVATIVES

Electrochemical oxidation of bis-(N,N'-bisethyl)ferrocene 1,1'-dicarbo xamide (1), N,N'-bis-[2(pyrrole-1 )ethyl]-N,N'-bisethylferrocene)-1,1' -dicarboxamide (2) and pyrrole-1-yl)ethyl]-N-ethylferrocene-1-carboxam ide (3) was investigated in 0.1 M TBAP/CH3CN by cyclic voltammetry (CV ) and chronoamperometry. In the potential range of 0-0.6 V a reversibl e diffusion-controlled process was observed with formal potentials of 0.30, 0.31 and 0.22 V, respectively. The diffusion coefficients of 1, 2, and 3 have been evaluated from both CV and chronoamperometric data. Polypyrrole films of 2 and 3 have been obtained potentiostatically (a t 0.85-1 V) and by CV on platinum and glassy carbon electrodes in 0.1 M TBAP/CH3CN. These films were tested in 0.1 M TBAF(4)/CH3CN, and 0.1 M TMABF(4) or LiClO4/H2O. The immobilized ferrocene is well characteri zed in CH3CN by a symmetrical shape signal and also has a satisfactory electrochemical response in water. The influences of monomer concentr ation and synthesis charge on the modified electrode performances were analysed. The observed linear dependencies of peak current on scan ra te and electropolymerization charge in agreement with the power law we re discussed. (C) 1997 Elsevier Science Ltd.