Electric-Field-Induced Covalent Condensation of Boronic Acids in Water Microdroplets

The influence of electric fields (EFs) on chemical reactions has attracted significant interest due to their ability to modulate reaction rates, pathways, and selectivity. Although EFs have been experimentally demonstrated to facilitate various reactions, clearer evidence for their role in covalent condensation has remained limited. Herein, we provide experimental evidence of electric-field-induced covalent condensation of boronic acids, utilizing the strong EFs at the air-liquid interface of microdroplets to induce the reaction. Microdroplet-based chemistry provides interfacial electric field intensities as high as ca. 109 V/m, offering a robust platform for the systematic investigation of boronate linkage formation and subsequent condensation of boronic acids. Our results confirm the role of EFs in facilitating room-temperature condensation of boronic acids, providing direct insights into the electric-field-induced polymerization process and presenting an experimental approach for investigating these processes in solution.