On-Surface Synthesis of Na-Porphyrins Using NaCl as a Convenient Na Source

Metallo-porphyrins with different metal centers display unique properties and are essential in various biological and chemical processes. Enormous efforts have been devoted to enriching the family of metallo-porphyrins on surfaces mainly through metalation processes within porphyrins and exogenous pure metals or intrinsic surface adatoms, which have focused on transition elements. However, less attention has been paid to the synthesis of alkali-metal-based porphyrins on a surface. Herein, by a combination of scanning tunneling microscopy (STM) imaging/manipulations and density functional theory (DFT) calculations, we report the fabrication of Na-porphyrins on Au(111) by introducing NaCl, i.e., two double-layered Na-centered porphyrins. Moreover, the interconversion between them was realized by precise STM manipulations. Our results demonstrate the feasibility of metalation by applying inorganic salt, which would serve as a promising strategy to embed intramolecular metal components into porphyrins for further functionalization and modification.