Catalysis and CO2 Capture by Palladium‐Incorporated Covalent Organic Frameworks

Abstract Triazine‐based imine and β‐ketoenamine linked covalent organic frameworks (COFs), TAT‐DHBD ( 1 ) and TAT‐TFP ( 2 ), have been synthesized from 1,3,5‐tris‐(4′‐aminophenyl)triazine (TAT) and 2,5‐dihydroxybenzene‐1,4‐dicarboxaldehyde (DHBD) or 1,3,5‐triformylphloroglucinol (TFP) under solvothermal conditions in dioxane/mesitylene mixture. These COFs exhibit significant surface areas owing to their meso‐ and micropores. The presence of basic nitrogen sites offers excellent affinity towards Pd nanoparticles and carbon dioxide. Post treatment of COFs 1 and 2 with palladium acetate gives Pd II /TAT‐DHBD ( 3 ) and Pd II /TAT‐TFP ( 4 ), which on reduction by NaBH 4 yields Pd 0 /TAT‐DHBD ( 5 ) and Pd 0 /TAT‐TFP ( 6 ), respectively. The new COFs have been characterized by FTIR, solid‐state 13 C NMR spectroscopy, X‐ray photoelectron spectroscopy (XPS), SEM, TEM, and Brunauer–Emmett–Teller (BET) surface area measurements. TEM studies corroborated the uniform distribution of Pd II and Pd 0 sites in the COFs. Compounds 3 – 6 are active towards the Suzuki–Miyaura cross‐coupling of arenes with meager catalyst leaching even after five cycles. In addition, 4 exhibits CO 2 uptake of 11 wt % and 7.5 wt % at 273 and 298 K, respectively, at 1 bar.