Aromatic bromination with hydrogen production on organic-inorganic hybrid perovskite-based photocatalysts under visible light irradiation

Aromatic bromides are important chemicals in nature and chemical industries. However, their traditional synthesis routes suffer from low atomic economy and pollutant formation. Herein, we show that organic–inorganic hybrid perovskite methylammonium lead bromide (MAPbBr3) nanocrystals stabilized in aqueous HBr solution can achieve simultaneous aromatic bromination and hydrogen evolution using HBr as the bromine source under visible light irradiation. By hybridizing MAPbBr3 with Pt/Ta2O5 and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate as electron- and hole-transporting motifs, aromatic bromides were achieved from aromatic compounds with high yield (up to 99%) and selectivity (up to 99%) with the addition of N,N-dimethylformamide or its analogs. The mechanistic studies revealed that the bromination proceeds via an electrophilic attack pathway and that HOBr may be the key intermediate in the bromination reaction.