A new microporous metal–organic framework with open metal sites and exposed carboxylic acid groups for selective separation of CO 2 /CH 4 and C 2 H 2 /CH 4

A new microporous metal–organic framework Cu6(DDCBA)3 (ZJU-72, H5DDCBA = 3,5-di(3′,5′-dicarboxylpheny)-benozoic acid) with open metal sites and exposed carboxylate groups is rationally designed and synthesized, exhibiting a low binding energy of 9.7 kJ mol−1 for C2H2 and 15.1 kJ mol−1 for CO2 and a high separation selectivity of 39.7 for C2H2/CH4 at 298 K and 8.2 for CO2/CH4 at 273 K.