Electrocatalytic C─S Cross-Coupling via Engineered Frustrated Lewis Acid-Base Pairs for High-Efficiency Methanesulfonate Synthesis.

The electrochemical synthesis of sulfonyl compounds under mild conditions remains a significant challenge due to the reliance on harsh reagents, high energy consumption, and low selectivity in conventional methods. Herein, we report a novel strategy for efficient C─S bond formation through in situ modulation of frustrated Lewis acid-base pairs within a copper-based metal-organic framework (CuBDC-XN). By precisely engineering electron-deficient Cu Lewis acid sites and electron-rich XN-functionalized Lewis base sites, this bifunctional catalyst enables the synergistic co-reduction of SO3 2- and CO2 into methanesulfonate (MS) at ambient conditions with a Faradaic efficiency of 13.77% (-0.78 V versus RHE). Mechanistic studies reveal that the frustrated Lewis pairs selectively stabilize key intermediates (*CHO and SO3 2-) via electrostatic interactions, facilitating nucleophilic attack and C─S coupling with a reduced energy barrier (0.48 eV). In situ spectroscopic analyses and DFT calculations further elucidate the dynamic adsorption-configuration regulation and intermediate evolution pathway. This work not only establishes a molecular-level understanding of cooperative Lewis acid-base catalysis but also provides a universal design principle for the sustainable electrosynthesis of value-added organosulfur compounds.