A Zn(ii)-functionalized COF as a recyclable catalyst for the sustainable synthesis of cyclic carbonates and cyclic carbamates from atmospheric CO₂

Abstract

A simple covalent organic framework (COF) bearing β-ketoenamine units as a potential heterogeneous ligand for ZnII-catalyzed fixation and transformation of CO2 into value-added chemicals is reported. Catalytic investigations convincingly demonstrated...

Light-Mediated Sustainable Conversion of Carbon Dioxide to Valuable Methanol by Highly Efficient Covalent Organic Framework g-C3N4 Composites as a Reusable Photocatalyst

“…Furthermore, the primary spectral bands associated with aromatic dialdehydes, located at around 2864 cm –1 (C–H stretching) and 1692 cm –1 (CO stretching), are absent in the spectra of the polymer materials. Such a decrease or absence in the absorption intensities of these bands serves as an indicator of an effective interaction between the amino and aldehyde groups to dehydrate. , Additionally, the characteristic peaks are present due to the CN stretching frequency of an imine group at 1599 and 1576 cm –1 was observed for the TRITER-1@g-C 3 N 4 composite and POP M 2 T 3 @g-C 3 N 4 composite, which is indicative of the effective integration of TAPT and melamine into the framework. In M 2 T 3 @g-C 3 N 4 , two additional peaks of C–H were observed at 2845 and 2731 cm –1 , which indicate the grafting of the g-C 3 N 4 composite onto the surface of POP M 2 T 3 .…”

Covalent Immobilization of Quaternary Ammonium Salts on Covalent Organic Framework: Sustainable Intensification Strategy for the Synthesis of Cyclic Carbonates from CO2

“…Tentative Reaction Mechanism. Based on previous reports, 41,91 a proposed mechanism for the cycloaddition of CO 2 to epoxides using quaternary ammonium salt integrated organocatalyst is depicted in Scheme 2. In order to understand the mechanism clearly, the most probable threestep mechanistic pathway facilitated by the functioning of the COF@CH 2 −CH 2 −Et 3 N + Br − center was proposed for the cycloaddition reaction of epoxides with CO 2 : activation of epoxide, CO 2 incorporation, and a subsequent intramolecular cyclization.…”

Metalated covalent organic frameworks: from synthetic strategies to diverse applications

“…In 2022, Islam et al grafted Zn( ii ) on a N-rich COF to obtain a Zn-metalated COF. 696 The obtained Zn@TpTta exhibits good catalytic activity in the fixation of CO 2 under sustainable conditions. The corresponding cyclic carbonates were generated in 69–99% yields in 1 atm CO 2 under solvent-free conditions.…”