Catechol‐Functionalized Covalent Organic Framework: Synthesis, Characterization and Metal‐Free Organocatalyst for CO₂ Fixation Under Mild Conditions

Covalent organic frameworks (COFs) incorporating hydrogen bond donor (HBD) moieties show great promise for heterogeneous catalyst for CO 2 cycloaddition. In this work, a catechol‐functionalized COF ( BL‐TF‐COF ) was constructed via Schiff‐base condensation under solvothermal conditions, which was characterized using powder X‐ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT‐IR), solid‐state 13 C nuclear magnetic resonance (NMR), scanning electron microscope (SEM), high resolution transmission electron microscope (HR‐TEM), diffuse reflection spectroscopy (DRS) and cyclic voltammetry (CV). BL‐TF‐COF presents high crystallinity, large surface area (523 m 2 g −1 ) and remarkable chemical stability, along with abundant hydroxyl functional groups distributed on the pore wall. This framework shows a CO 2 adsorption capacity up to 88 mg g −1 at 273 K and 1 bar. The binding locations of the adsorption of CO 2 over BL‐TF‐COF was studied by grand canonical Monte Carlo (GCMC) simulations. BL‐TF‐COF displays remarkable catalytic performance for the cycloaddition of CO 2 with epoxides under mild conditions. Under the condition of the epichlorohydrin/tetrabutylammonium bromide/ BL‐TF‐COF molar ratio of 10210:630:4, the system achieved 62.5% substrate conversion at 25 °C under atmospheric CO 2 pressure (1 bar) within 48 h. Mechanistic insights into epoxide adsorption and activation processes were investigated through density functional theory (DFT) calculations.