Synthesis, characterization and photophysical studies of β-triazolomethyl-bridged porphyrin-benzo-α-pyrone dyads

Abstract

A new series of zinc(II) β-triazolomethyl-bridged porphyrin-benzo-α-pyrone dyads have been synthesized in appreciable yields through a copper(I)-catalyzed "click" reaction of zinc(II) 2-azidomethyl-5,10,15,20-tetraphenylporphyrin with various benzo- a-pyronoalkynes. These novel zinc(II) porphyrin-benzo-α-pyrone dyads successfully underwent demetallation in the presence of concentrated hydrochloric acid in chloroform at 25°C to form the corresponding free-base porphyrin analogues in good yields. The newly synthesized products were characterized on the basis of spectral data and evaluated for their electronic absorption and fluorescence properties. Some of these molecules have shown a significant intramolecular energy transfer between the benzo-α-pyrone and porphyrin subunits.