Redox active surface films produced by electrooxidation of substituted indolysines

The electrochemical oxidation of substituted mono-and 3,3′-biindolysines is studied by methods of cyclic voltammetry and electron spin resonance (ESR) combined with in situ electrolysis. In acetonitrile, there occurs easy irreversible electrochemical oxidation and proceed processes of association of generated radical cations via unsubstituted positions of five-membered cycles. Polymeric products of oxidation of 2-arylindolysines, 3-indolysine-2-yl-quinoxalines, and 2,2′-diaryl-3,3′-biindolysines are obtained when cycling potential in the interval −0.3 V → +0.8 V → −1.3 V → −0.3 V (Fc/Fc + ). The products deposit on the electrode with the formation of redox-active films that are capable of undergoing reversible oxidation with the formation of stable paramagnetic states registered by the ESR method.