Decavanadate Supported on Carbon Nitride Nanosheets as Photocatalysts for Selective C–H Bromination of Arenes Using KBr

Abstract

The photocatalytic bromination of arene C−H bonds is a crucial and sustainable transformation in organic synthesis chemistry. However, traditional methods suffer from low efficiency, poor selectivity, and environmental concerns of bromine sources. Herein, we report a decavanadate-modified graphite nitride carbon catalyst (V 10 -g-C 3 N 4 ) that exhibits remarkable performance in the bromination of arene, utilizing nontoxic KBr as a bromine source under visible-light irradiation. The "electron sponge" property of decavanadate in catalysts not only enhances catalytic activity by suppressing the recombination of photogenerated carriers (electrons and holes) but also improves the activation of molecular oxygen via single-electron transfer (SET), further enhancing catalytic efficiency. In addition, the electrostatic interaction between decavanadate and graphite nitride carbon exhibited high stability and activity after five cycles, without a significant decrease. g-C 3 N 4 primarily absorbs substrates through π−π interactions, while decavanadate offers Lewis-acid-type anchoring sites for O 2 , enabling the activation of both substrates and O 2 through the SET process. Fluorescence quenching, radical trapping, and electron paramagnetic resonance (EPR) experiments highlight the pivotal importance of holes in enhancing substrate activation, while underscoring the crucial role of electrons in activating O 2 to • O 2 − . This work provides insights into the interaction between the decavanadate and organic semiconductor, enabling light-induced molecular transfer in green and sustainable chemistry.