Electric-Field-Mediated Molecular Scalpel for Programmable Cleavage and Reconfiguration of Monolayer Covalent Organic...

Monolayer covalent organic frameworks (COFs) featuring reversible linkages have emerged as promising platforms for dynamic structural reconfiguration. However, achieving programmable depolymerization and reconstruction of robust imine COFs remains a significant challenge. Here we present an "electric-field-mediated molecular scalpel" strategy that combines a localized electric field with bias-responsive boronic acid molecules to achieve localized C═N bond cleavage and nanoscale reconstruction, enabling precise patterning of in-plane imine/boroxine COF hybrid framework. In situ STM reveals a gradual depolymerization mechanism. Kinetic analysis, liquid-phase atomic force microscopy (AFM), nuclear magnetic resonance (NMR), and molecular dynamics (MD) simulations collectively validate a new electric-field-mediated interfacial reconfiguration mechanism of "adsorption-activation-transformation". In this process, boronic acid molecules compete for surface sites, destabilizing the imine lattice and promoting its depolymerization. This work provides the first (sub)molecular-level insight into the dynamic depolymerization of imine COFs and, with nanometer precision, enables the construction of in-plane hybrid framework between imine and boroxine COFs, thereby establishing a generalizable framework for electric-field-mediated nanoscale molecular engineering.