Construction of C═N/C─N Bonds From N₂ Driven by Sheath Electric Field at Nonaqueous Microdroplet Interfaces

Conventional imine synthesis relies on amine feedstocks as the nitrogen source, often requiring specific functional groups and harsh reaction conditions. Herein, we report a synergistic plasma-nonaqueous-microdroplet platform for the one-step, catalyst-free synthesis of imines directly from N₂ and hydrocarbons. Reaction kinetics are significantly enhanced by a sheath electric field generated at the interface between the plasma and the neutral nonaqueous microdroplets. This interfacial electric field facilitates the activation of alkane C─H bonds and insertion of nitrogen cations. C═N bond formation proceeds with exceptional selectivity, yielding primary ketimines (>99% in pure N₂ and 80% in air). Subsequently, the C(sp³)─H bonds of alkylbenzenes are selectively activated to form C(sp³)─N═C(sp²) linkages, controllably yielding valuable platform molecules of Schiff bases/secondary ketimines. Combined experimental and theoretical investigations elucidate the mechanism of this N-cation-mediated C─H activation at the molecular level. This work establishes an atom-efficient and sustainable route for imine synthesis, demonstrating a broadly applicable pathway for N₂ fixation and C─H bond activation under mild conditions across a diverse substrate scope.