Reductive polymerization of Para-cyanobenzaldehyde in dimethyl sulfoxide solutions using the rotating ring-disk electrode technique

The rotating ring-disk electrode (RRDE) technique has been employed to study the reductive polymerization mechanism of para-cyanobenzaldehyde (CBA) in dimethyl sulfoxide (DMSO) solutions. The radical anion of CBA underwent polymerization through two different reaction routes. They were found to be the successive parent molecule addition to the radical anion reactions and the dimerization of the radical anion followed by parent molecule additions. Digital simulation methods were employed to simulate the mechanism and to obtain the second-order reaction rate constants of the radical anions from collection efficiency measurements. The reaction rate constants were found to be 1.45 M^?1 s^?1 for reactions of the radical anion with the parent molecules, and 28.6 M^?1 s^?1 for dimerization of the radical anion followed by trapping a parent molecule immediately after the dimeric dianion is generated.