Porous Metal–Organic Frameworks with Chelating Multiamine Sites for Selective Adsorption and Chemical Conversion of Carbon Dioxide

A combination of carbon dioxide (CO₂) capture and chemical fixation in a one-step process is attractive for chemists and environmentalists. In this work, by incorporating chelating multiamine sites to enhance the binding affinity toward CO₂, two novel metal–organic frameworks (MOFs) [Zn₂(L)­(2,6-NDC)₂(­H₂O)]­·1.5DMF­·2H₂O (<b>1</b>) and [Cd₂(L)­(2,6-NDC)₂]·1.5DMF·2H₂O (<b>2</b>) (L = <i>N</i>¹-(4-(1<i>H</i>-1,2,4-triazole-1-yl)­benzyl)-<i>N</i>¹-(2-aminoethyl)­ethane-1,2-diamine, 2,6-H₂NDC = 2,6-naphthalenedicarboxylic acid, DMF = <i>N</i>,<i>N</i>-dimethylformamide) were achieved under solvothermal conditions. Both <b>1</b> and <b>2</b> possess high selectivity for adsorption of CO₂ over CH₄ at room temperature under atmospheric pressure. Moreover, <b>1</b> has one-dimensional tubular channels decorated with multiactive sites including NH₂ groups and coordination unsaturated Lewis acid metal sites, leading to efficient catalytic activity for chemical fixation of CO₂ by reaction with epoxides to give cyclic carbonates under mild conditions