Tuning the Catalytic Activity of Covalent Metal-Organic Frameworks for CO 2 Cycloaddition Reactions.

The development of efficient, recyclable and low-cost heterogeneous catalysts for conversion of carbon dioxide (CO 2 ) into epoxides is highly desired, yet remain a challenge. Herein, we have prepared three two-dimensional (2D) copper(I) cyclic trinuclear units (Cu(I)-CTUs) based covalent metal-organic frameworks (CMOFs), namely JNM-13, JNM-14, and JNM-15, via a one-pot reaction by combination of coordination and dynamic covalent chemistry. Among them, JNM-15 contained the highest density of copper catalytic sites, and exhibited the highest capacity for adsorption of CO 2 . More interestingly, JNM-15 delivered the highest catalytic activity for cycloaddition of CO 2 to epoxides with good yields (up to 99 %), good substrate compatibility (11 examples) and reusability (four catalytic cycles) under mild condition.