Application of single-sweep polarography to the investigations of cyanopyridine redaction

The anomalous minima on the current-voltage curves of 4-cyano- and 2-cyanopyridine in the medium pH range in classical d.c. polarography can be elucidated by means of single-sweep polarography and controlled-potential electrolysis. The mechanism of the electrode reaction changes with potential. The fission of the C-C bond between the heterocyclic nucleus and the nitrilo group is predominant at more negative potentials, whilst picolylamine is the main product of the electro-reduction at the beginning of the limiting current.

Observations with single-sweep polarography indicate the participation of a short-lived radical in the electroreduction of 3-cyanopyridine.