First successful synthesis of polypyridines in ionic liquid: Role of 1‐butyl-3-methylimidazolium tetrafluoroborate as electrolyte

- For the first time a scheme mechanism of electrooligomerisation of pyridine in ionic liquid is proposed.
- The mechanism is based on electrochemical characterization reduction of pyridine on rhenium and platinum electrodes to an anion- radical.
- The formation of the oligomeric product doped with cations of the ionic liquid is proposed.

Electrochemical reactions of pyridine in the 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid (IL) were investigated by cyclic voltammetry. The electrochemical characterization provides evidence that pyridine can be reduced on rhenium and platinum electrodes into an anion-radical in the ionic liquid based on the imidazolium cation. The comparative study of Re and Pt electrodes was done for the first time. Under anodic potential sweep, the product of cathodic reduction of pyridine is further transformed into an oligomeric product that is soluble in the ionic liquid. A scheme of formation of the conductive oligomer is proposed. SEM pictures of the rhenium and platinum surfaces after 100 cycles in the IL with dissolved pyridine are presented. Conjugated polymers can be doped with cations or anions of the electrolyte. The formation of the oligomeric product doped with cations of the ionic liquid is proposed.