Precise fabrication of ternary ordered covalent organic frameworks for photocatalysis

Despite the great success in the synthesis of binary covalent organic frameworks(COFs)in the past decade,the fabrication of structurally ordered ternary COFs remains a big challenge,due to the inevitable competition and exchange of monomers.Herein,two ternary ordered COFs(2Me-OMe-COF and Me-2OMe-COF)are successfully synthesized by two-step polymerization based on irreversible covalent bonds.In contrast to the ternary random COFs synthesized by one-pot method,ternary ordered COFs possess definite structures at the molecular level.Accordingly,we systematically compare the performance of the two ternary ordered COFs in photocatalytic H_(2)production with two corresponding binary COFs as controlled comparison.Significantly,they exhibit very different photocatalytic performance,highlighting the importance of component and structural order for their properties.This work provides a unique strategy to the targeted polymerization and synthesis of ternary ordered,or even multivariate ordered COFs.

Atomically Precise Imprinting π-Magnetism in Nanographenes via Probe Chemistry

The precise generation and harnessing of carbon magnetism at the single-molecule level have been captivating areas of research in chemistry and nanotechnology.However,the realization of magnetic nanographenes,also known as single-moleculeπ-magnets,through solution-based synthesis has proven challenging because of their high reactivity and insolubility tendency.Recent advancements in on-surface chemistry and scanning probe techniques have significantly propelled the fabrication of carbon-based magnetic nanostructures to offer a rich platform to probe quantumπ-magnetism at the single-molecule level.Atomic manipulation,also referred to as probe chemistry,stands as an exciting and essential approach in the toolbox of on-surface chemistry.This approach enables site-selective chemical reactions,thereby allowing for the atomically precise imprinting and tailoringπ-magnetism in a variety of nanographenes.This review highlights the recent achievements in the precise synthesis of single-moleculeπ-magnets using atomic manipulation.Furthermore,we also provide an outlook on the future of probe chemistry in the fabrication of this intriguing class of magnetic nanographenes,featuring designer quantum magnetism.