Dynamic porous metal–organic frameworks: synthesis, structure and sorption property

Abstract

Three new porous metal–organic frameworks {[Co(L)(PIN)]·dioxane·H₂O}_n (1), {[Co(L)(DPE)]·0.5DPE}_n (2) and {[Co(L)(BPE)]·4H₂O}_n (3) with the same 2-fold interpenetrating hms topology based on 5-(pyridin-4-yl)isophthalate (L²⁻) and different pillar ligands of N-(4-pyridyl)isonicotinamide (PIN), 1,2-di(4-pyridyl)ethylene (DPE) and 1,2-bis(4-pyridyl)ethane (BPE) have been prepared and characterized by IR, thermogravimetric analysis, single crystal and powder X-ray diffractions. Interestingly, 1 possesses a flexible framework upon desolvation and H₂O/MeOH/EtOH vapor adsorption, and the desolvated sample exhibits a stepwise uptake of CO₂ (195 K), H₂O (298 K) and MeOH (298 K). More importantly, the desolvated 1 shows high enthalpy of CO₂ adsorption and high selectivity for CO₂ over N₂ as well as H₂O/MeOH over EtOH at 298 K.