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

Abstract

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.