Two comparable Ba-MOFs with similar linkers for enhanced CO_(2)capture and separation by introducing N-rich groups

摘要

Two new different metal-organic frameworks(MOFs)[Ba(L1)(H_(2)O)_(2)]_(n)·nH_(2)O(MOF 1)and[Ba(L2)(-n2 O)_(2)]_(n)·0.5 nDMF·0.5 nH_(2)O(MOF 2)were yielded by the assembly of oxygen-friendly Ba(Ⅱ)ions and two similar linkers,namely 2-(imidazol-1-yl)terephthalic acid(H_(2)L1)and 2-(1 H-1,2,4-triazol-1-yl)terephthalic acid(H_(2)L2).Single-crystal X-ray diffractions(XRD)indicate that MOF1 is a new three-dimensional(3 D)stacking dense network formed by the one-dimensional(1 D)rod-shaped chains and L1 linkers,whereas MOF 2 presents a 3 D nanotube porous framework with cylindrical tunnels based on the 1 D loop chains as the secondary building units(SBUs)by replacing the imidazole group in H_(2)L1 with the triazole group in H_(2)L2.As a result,MOF 2 has a higher density of active sites and Lewis acid sites in the porous surface of nanotube than MOF 1.Thereby,the CO_(2)capture and separation capacity of MOF 2 is great higher than that of CH_(4)at298 K.