Fine-Tuning the Porosities of the Entangled Isostructural Zn(II)-Based Metal-Organic Frameworks with Active Sites by Introducing Different N-Auxiliary Ligands: Selective Gas Sorption and Efficient CO2 Conversion

摘要

Three new pairs of 2-fold interpenetrated and self-entangled three-dimensional isostructural porous metal-organic frameworks (MOFs), [Zn(L1)(x)(0.5)]center dot 0.5H(2)O (x = bipy for 1, bpa for 2, and bpe for 3) and [Zn(L2)(x)(0.5)]center dot 0.5H(2)O (x = bipy for 4, bpa for 5, and bpe for 6) [bipy = 4,4'-bipyridine, bpe = 1,2-bis(4-pyridyl)-ethylene, and bpe = 1,2-bis(4-pyridyl)ethylene], have been created and fine-tuned via similar skeleton ligands 2-(imidazol-1-yl)terephthalic acid (H(2)L1) and 2-(1H-1,2,4-triazol-1-yl)terephthalic acid (H(2)L2) and N-auxiliary coligands with different linking groups. Interestingly, the porosities of the MOFs can be effectively increased via the insertion of -CH2CH2- or -CH=CH- spacers into the N-auxiliary bipy ligand. As a result, complexes 5 and 6 displayed highly enhanced CO, uptake capacities. Furthermore, complex 5 also had a higher C-2/C-1 selectivity as well as great CO2 cycloaddition efficiency.