Redox-active tetra-amino cobalt phthalocyanine electrocatalyst for sustainable electrochemical synthesis of 2-(pyridin-4-yl)-1H-benzo[d]imidazole

An electrocatalyst bearing a cobalt phthalocyanine derivative was developed by modifying carbon fibre paper electrode with polythiophene-3-acetic acid (pTAA) and further immobilizing tetra-amino cobalt phthalocyanine (TACoPc). The electrode was topographically and electrochemically characterized to validate its surface modification and functional suitability. This energy efficient electrocatalyst (CFP-TAA-TACoPc) was explored, for the sustainable synthesis of 2-(pyridin-4-yl)-1 H -benzo[ d ]imidazole at 1.35 V, with 87.6 ± 1.267 % product yield at ambient conditions. o -phenylenediamine and pyridine-4-carboxaldehyde were used as starting materials, with ethanol as solvent, and lithium perchlorate as supporting electrolyte, using a three-electrode system, in a single compartment cell. The benzimidazole derivative was observed to crystallize out after completion of the reaction, negating the need for any further purification and was characterized using 1 HNMR and GC–MS. This work highlights the potential of electrochemical strategies as a sustainable and efficient alternative to conventional methods for heterocyclic synthesis.