Bifunctional catalyst based on functionalization of metal-organic frameworks for the chemical fixation of CO2 under Co-catalyst and solvent free conditions

•Nucleophilic functional groups were successfully constructed on unsaturated indium- based frameworks for highly effective CO2 cycloaddition reactions.•This is the first report utilizing the novel modified CPM-6 with nucleophilic groups as catalyst for fixation of CO2 into cyclic carbonates.•The modified CPM-6 has a good catalytic activity in the aspect of CO2 cycloaddition reactions without co-catalyst and solvent.•The bifunctional synthesized 3D porous indium frameworks demonstrate remarkable conversion and high TON. Catalyst design for carbon dioxide (CO2) cycloaddition reaction and epoxides requires an efficient approach toward synergetic cooperation acid-base sites effect. This study introduces a new series of bifunctional heterogeneous catalysts based on indium framework known as crystalline porous materials (CPM)-6 with various nucleophilic groups, featuring high CO2 conversion and selective for cyclocarbonates synthesis. CPM-6 was solvothermally synthesized and subsequently post-synthetically modified with three nucleophilic groups of 2-bromoaniline, 2-aminophenol, and 2-nitroaniline. CPM-6-Br framework revealed the highest catalytic activity and selectivity (100 % conversion and 100 % selectivity) upon the cycloaddition of CO2 under mild conditions (70 °C, 1 Mpa CO2 pressure, and 12 h) and co-catalyst, solvent free which is related to the coexistence and bifunctional synergistic action of the acid sites and basic sites in the catalyst. [Display omitted]