Keggin type heteropolyacid-mediated novel green protocol for the synthesis of porphyrins

Abstract

The unique and highly tunable photophysical, photochemical and photoredox properties of porphyrins contribute to their versatile applications in alternate energy generation, sensing, and therapeutic fields. The synthetic route for meso substituted porphyrins involves acid-catalysed condensation of aldehyde and pyrrole followed by oxidation. Herein, we report an environmentally benign novel approach for the synthesis of substituted tetraaryl porphyrins using acetonitrile as the solvent and Keggin type phosphovanadotungstic acid as the catalyst. The simple one-pot strategy completely avoids the usage of acidic/chlorinated solvents and expensive oxidising agents. A reasonable spectroscopic yield of around 12–39% could be obtained for various derivatives under the optimised conditions.