Microporous Metal–Organic Framework Based on a Bifunctional Linker for Selective Sorption of CO₂ over N₂ and CH₄

A bifunctional organic linker 4-(4-carboxyphenyl)-1,2,4-triazole (HCPT), incorporating both carboxylate and triazole groups, has been successfully used in the construction of a 2-fold interpenetrated dynamic metal–organic framework (MOF), {[Cu₃(CPT)₄(μ₃-OH)]·NO₃·7H₂O·EtOH}<i>_n</i> (<b>1</b>) based on a triangular Cu­(II)-hydroxo cluster as secondary building unit (SBU). Upon solvation/desolvation and temperature, the crystal cell parameters of <b>1</b> could be fine-tuned. More importantly, a transformation from disordered phase to a more ordered phase after activation was observed via a single-crystal-to-single-crystal mode. Gas sorption studies reveal that the activated <b>1</b> exhibits highly selective sorption of CO₂ over N₂ and CH₄ at room temperature