Sulfur quantum dots-assisted functionalization of aryl radicals towards metal-free cross-coupling

Abstract

Sulfur quantum dots (SQDs) exhibit size-dependent optical properties and redox potentials, and their surfaces can be easily modified with a variety of ligands, making them promising candidates for photocatalysis. In this study, ethanolamine-functionalized sulfur quantum dots (ETA-SQDs) with short-chain ligands were synthesized for biaryl cross-coupling reactions under air atmosphere. The Auger effect of the quantum dots also facilitates electron transfer to aryl bromides, resulting in highly efficient dehalogenation. Mechanistic studies highlight the critical role of surface ligands in the catalytic process. These ETA-SQDs demonstrate excellent photocatalytic performance, capable of forming charge transfer complexes with substrates to oxidize N-methylpyrrole, eliminating the need for additional reducing agents. These findings suggest that functionalized SQDs offer significant potential for a wide range of photocatalytic applications.