Photoelectrochemical-induced heterogeneous catalytic selective dehalogenation coupling of alkyl halides with thiophenols via interfacial charge transfer†

Abstract

Electrophotocatalytic synergistic systems offer novel mechanisms for redox transformations, yet conventional approaches face challenges in sustainability and scalability. Existing electrophotocatalytic reductive dehalogenation coupling methods suffer from homogeneous dye dependency, complex divided-cell setups, and limited substrate compatibility. Herein, we present a green and energy-efficient photoelectrochemical strategy for selective dehalogenation coupling of alkyl halides with thiophenols via interfacial charge transfer (ICT), employing a recyclable poly(heptazineimide)/In₂S₃ (PHI/In₂S₃) heterojunction photocatalyst. By applying an external bias potential, we effectively suppress photoelectron–hole recombination, achieving up to 84% yield under mild conditions (room temperature, ambient air, undivided cell) with a turnover number (TON) of up to 14 090. This approach eliminates the need for sacrificial reagents, toxic solvents, or energy-intensive setups, while enabling efficient cleavage of C–F/C–Cl/C–Br bonds. Key green chemistry advantages include: (1) heterogeneous catalyst design allowing facile recovery and reuse (76% yield retention after 5 cycles); (2) simplified operation in undivided cells to minimize energy and material waste; (3) broad substrate scope under ambient conditions, reducing hazardous byproduct formation; and (4) atom-economical synthesis of pharmaceutically relevant dithioacetals. This work establishes a sustainable paradigm for dehalogenation chemistry by integrating photoelectrochemical activation with heterogeneous catalysis.