Controlling the Selectivity of Reaction Products by Transmetalation on a Ag(111) Substrate.

On-surface synthesis has shown great promise in the precise bottom-up preparation of molecular nanostructures. Apart from the direct C-C coupling reaction pathway, an alternative strategy is to exploit the metal-organic interactions provided by integrated metals for preassembly, which exhibit high reversibility and can anchor specific conformations of molecular precursors, thus allowing the precise construction of nanostructures with improved reaction selectivity. Previous studies have mainly been devoted to the construction of target reaction products through the incorporation of metal atoms, ranging from intrinsic to extrinsic atoms on metal substrates and, more recently, to their cooperative effects. However, the formation of different covalent nanostructures by competitive interactions between intrinsic and extrinsic adatoms remains elusive. Herein, we controlled the selectivity of covalent reaction products from isomerically specific -chains to -rings, resulting from the transmetalation of intrinsic Ag adatoms to extrinsic Na atoms on a Ag(111) substrate. Our results exhibit the competitive interactions between intrinsic and extrinsic metal atoms in real space and demonstrate their influence on the selectivity of reaction products, which should broaden the regulatory strategies for on-surface synthesis that shed light on the controllable and selective synthesis of target covalent nanostructures.