Reversible Self‐Assembly of an N‐Heterocyclic Carbene on Metal Surfaces

摘要

Abstract Self‐assembly of cyclohexyl cyclic (alkyl)(amino)carbenes (cyCAAC) can be realized and reversibly switched from a close‐packed trimer phase to a chainlike dimer phase, enabled by the ring‐flip of the cyclohexyl wingtip. Multiple methods including scanning tunneling microscopy (STM), X‐ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations identified a distinct isomer (axial or equatorial chair conformer) in each phase, and consequently support the conclusion regarding the determination of molecular surface geometry on the self‐assembly of cyCAAC. Moreover, various substrates such as Ag (111) and Cu (111) are tested to elucidate the importance of cyCAAC‐surface interactions on cyCAAC based nanopatterns. These investigations of patterned surfaces prompted a deep understanding of cyCAAC binding mode, surface geometry and reversible self‐assembly, which are of paramount significance in the areas of catalysis, biosensor design and surface functionalization.