On-liquid surface synthesis of diyne-linked two-dimensional polymer crystals.

The synthesis of thin crystalline two-dimensional polymers (2DPs) typically relies on reversible dynamic covalent reactions. While substantial progress has been made in solution-based and interfacial syntheses, achieving 2DPs through irreversible carbon-carbon coupling reactions remains a formidable challenge. Herein, we present an on-liquid surface (a mixture of N,N-dimethylacetamide and water, DMAc-H2O) synthesis method for constructing diyne-linked 2DP (DY2DP) crystals via Glaser coupling, assisted by a perfluoro-surfactant (PFS) monolayer. In-situ spectroscopic and diffraction techniques reveal that the well-ordered PFS monolayer facilitates the accumulation of Cu+ ions and subsequent vertical coupling of acetylenic monomers on the DMAc-H2O surface. Building on these findings, we successfully synthesized micro-scale rod-shaped DY2DP-Por or graphdiyne (GDY) crystals through the polymerization of porphyrin- or benzene-based monomers, respectively. Our study represents a significant advancement in the field of on-liquid surface chemistry and opens up enormous opportunities for constructing C-C bond linked 2DP crystals with unique functionalities.