Two isomeric Zn(ii)-based metal–organic frameworks constructed from a bifunctional triazolate–carboxylate tecton exhibiting distinct gas sorption behaviors

Two isomeric Zn(II)-based metal–organic frameworks, {[Zn(CPT)2](NMF)3}n (1) and {[Zn(CPT)2](DMF)0.75}n (2) (HCPT = 4-(4-carboxyphenyl)-1,2,4-triazole, NMF = N-methylformamide, DMF = N,N-dimethylformamide), with the same 4-fold interpenetrated dia topological network have been prepared under solvothermal conditions by employing a bifunctional triazolate–carboxylate organic linker, which show very similar voids but different pore shapes. Thermogravimetry, powder X-ray diffraction, molecular mechanics calculation, and gas sorption studies revealed their different framework stabilities and flexibilities, in which desolvated 1 exhibits temperature-dependent stepwise and hysteretic selective sorption of CO2 over N2 at 195 K, whereas desolvated 2 could adsorb neither CO2 nor N2. Furthermore, the luminescence properties of 1 and 2 were investigated.