Covalent organic frameworks are an emerging class of porous crystalline organic materials that can be designed and synthesized from the bottom up. Despite progress made in synthesizing COFs of diverse topologies, the synthesis methods are often tedious and unscalable, hampering practical applications. Herein, we demonstrate a scalable, robust method of producing highly crystalline acylhydrazone two-dimensional (2D) COFs with diversified structures (six examples) under open and stirred conditions, with growth typically completed in only 30 min. Our strategy involves selecting molecular building blocks that have bond dipole moments with spatial orientations that favor antiparallel stacking and whose structure allows the restriction of intramolecular bond rotation (RIR) via intra-and interlayer hydrogen bonding. This method is widely applicable for hydrazide linkers containing various side-chain functionalities and topicities. By this strategy, the gram-scale synthesis of two highly crystalline COFs (up to 1.4 g yield) was obtained in a one-pot reaction within 30 min.

Porphyrin-based isostructural porous organic networks have been synthesized by varying the central metal atoms to cobalt, nickel and copper. Their selectivities for CO2 capture over N2 and Ar are found to be enhanced as the heats of adsorption for CO2 are increased in the order of Co, Ni and Cu, while the pore structures are well maintained.

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We report the quadruple metals-based layered structure giving a high selectivity close to 100% and a significantly improved efficiency for photocatalytic conversion of CO2 to CO compared to bi or tri metals-based layered ones.