Light assisted nickel(II) grafted-g-carbon nitride molecular hybrid promoted hydrocarboxylation of olefins with CO2 at atmospheric pressure condition

Abstract

An efficient photocatalytic method was developed for the hydrocarboxylation of olefins to corresponding acids using carbon dioxide assisted by a molecular hybrid photocatalyst consisting of nickel phthalocyanine complex grafted to graphitic carbon nitride support (NiPc/g-C3N4) under ambient temperature and pressure conditions. The reaction is found to be regioselective in nature as aromatic olefins i.e. styrenes and its derivatives afforded α-carboxylated products; whereas aliphatic olefins yielded terminal acids selectively in moderate-to-good yields. The DFT calculations suggested the higher efficiency of the hybrid photocatalyst as compared to its individual components. Based on the electrochemical measurements and adsorption behaviour of the CO2 on the catalyst and corresponding bond distances calculated by DFT, a possible mechanism is proposed. Furthermore, triethylamine was used as a sacrificial donor that provided the required electrons to complete the redox cycle of the reaction.