Seeing the Unseen: Spatio-temporal Visualization of Reactive Carbocation Intermediates in Electrolytic Cells

In an electrolytic cell, reactive carbocations often emerge as key intermediates during oxidative electrochemical transformations, particularly near the anode. Owing to their short lifetimes and high electrophilicity, these species are typically challenging to detect directly in situ. This study employed spatial and temporal sampling of some electrochemically driven C–O, C–N, and C–C bond-forming reactions, followed by rapid analysis of the collected aliquots using desorption electrospray ionization mass spectrometry. The captured carbocations were then visualized through a contour plot representing their abundance across the electrolytic cell. This spatio-temporal resolution of reactive intermediates enables transforming electrochemical studies from static end-point analysis to dynamic, mechanistically rich investigations, offering detailed insights into the formation, transformation, and diffusion of key intermediates in spatial and temporal dimensions.