Construction of stable MOFs integrated with open metal sites and amine groups for CO2 capture and conversion

CO 2 is deemed as the major greenhouse gas causing global warming over the past several decades. Developing porous solid materials to achieve the capture and utilization of CO 2 , in this work, two metal–organic frameworks (MOFs), [Ni 2 (5H-Ade)(TCPE)(H 2 O) 3 ]∙3DMF∙6H 2 O (Ni-Ade-TCPE), and [Co 4.5 (HCOO) 3 (4H-Ade) 2 (TCPE)(H 2 O) 5 ]·5DMF·7H 2 O (Co-Ade-TCPE) have been synthesized by employing mixed adenine and tetrakis(4-carboxyphenyl)ethylene (H 4 TCPE). The structural analysis demonstrates they are 3D frameworks possessing 1D open channels with –NH 2 groups and open metal sites modified surfaces. They display impressive chemical stability in acidic and basic water solutions and high adsorption capacity for CO 2 . At 70 °C and 1 bar, Ni-Ade-TCPE exhibits outstanding activity, selectivity, and recyclability in the cycloaddition reaction of epoxides with CO 2 due to Lewis acid–base bifunctional sites. Moreover, a reasonable catalytic reaction mechanism has been proposed. Two stable MOFs, Ni-Ade-TCPE and Co-Ade-TCPE, based on a mixed-ligand strategy were synthesized, which are 3D microporous structures with 1D open channels decorated by –NH 2 sites. They show good chemical stability in water, acidic and alkaline solutions, and high CO 2 uptake. Ni-Ade-TCPE exhibits high performances in catalyzing cycloaddition of CO 2 with epoxides under mild conditions. • Two MOFs with multiple functional sites have been synthesized based mixed ligands. • They display high chemical stabilities in acidic and basic aqueous solutions. • Ni-Ade-TCPE can efficiently catalyze the conversion of CO 2 with different epoxide.