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) [Zn-2(L)(2,6-NDC)(2)(H2O)]center dot 1.5DMF center dot 2H(2)O (1) and [Cd-2(L)(2,6-NDC)(2)]center dot 1.5DMF center dot 2H(2)O (2) (L = N-1-(4-(1H-1,2,4-triazole-1-yl)benzyl)-N-1-(2-aminoethyl)ethane-1,2-diamine, 2,6-H2NDC = 2,6-naphthalenedicarboxylic acid, DMF = N,N-dimethylformamide) were achieved under solvothermal conditions. Both 1 and 2 possess high selectivity for adsorption of CO2 over CH4 at room temperature under atmospheric pressure. Moreover, 1 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.