One-pot synthesis of β-carboxy tetra aryl porphyrins: potential applications to dye-sensitized solar cells

Abstract

A facile one-pot mild reaction condition for the conversion of 2-formyl-5,10,15,20-tetra aryl-substituted porphyrins and their zinc derivatives to the corresponding 2-carboxy-5,10,15,20-tetra aryl-substituted porphyrins was achieved for the first time by using hydroxylamine hydrochloride and phthalic anhydride. A facile one-pot conversion of 2-formyl-5,10,15,20-tetra aryl-substituted porphyrins and their zinc derivatives to the corresponding 2-carboxy-5,10,15,20-tetra aryl-substituted porphyrins was achieved for the first time by using hydroxylamine hydrochloride and phthalic anhydride. All these substituted carboxy porphyrins were completely characterized by using mass, CHN analysis, 1 H NMR, UV–vis, Fluorescence spectroscopies, and cyclic voltammetry. Both the absorption maxima and emission maxima were red shifted by 5–7 nm. The LUMO of these porphyrins are above the TiO 2 conduction band and HOMO was below the redox electrolytes. These carboxy porphyrins are potential applications as sensitizers to dye-sensitized solar cell.