title: Ligand Torsion Triggered Two Robust Fe-Tetratopic Carboxylate Frameworks with Enhanced Gas Uptake and Separation Performance.
abstract: By regulating the tetratopic carboxylate ligands, two robust Fe-MOFs (MOF=Metal-organic framework) comprising trigonal prismatic building blocks under a DMA/DMSO/HBF4solvent system, namely, [(CH3)2NH2][FeII3(OH)(BPTC)1.5(DMSO)3] (SNNU-60) and [FeIIIFeII2(OH)(ABTC)1.5(DMSO)3] (SNNU-61) (BPTC=3,3',5,5'-biphenyltetracarboxylic acid, ABTC=3,3',5,5'-azobenzenetetracarboxylic acid, SNNU=Shaanxi Normal University) have been successfully synthesized. The torsions between the benzene groups of the ligands result in two MOFs exhibiting completely different (4,6)-connected frameworks, which represent the only two MOF types constructed by [M3(O/OH)(COO)6] trimeric building units and quadrilateral tetratopic carboxylate linkers until now. The robust Fe-MOFs SNNU-60 and SNNU-61 both exhibit high thermal/chemical stability, permanent microporosity, and excellent gas uptake capability for H2, CO2, C2H2, and C2H4under 1 bar. SNNU-60 in particular displays very high C2H2capture under low pressure (85 cm3cm-3at 0.15 bar and 298 K), which is among the top C2H2uptake MOF materials. Also, these two Fe-MOFs display high separation for CO2and C2-hydrocarbons over CH4. Significantly, thanks to the high stability, suitable pore size, open Fe sites, and ion skeleton, SNNU-60 has extremely high C2H2/CH4selectivity (83.6, 298 K), which surpasses most MOFs reported so far under the same conditions.
authors.affiliation: Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi, 710062, P. R. China.
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi, 710062, P. R. China.
authors.forename: Man-Cheng
authors.initials: MC
authors.lastname: Hu
authors.affiliation: Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi, 710062, P. R. China.
authors.forename: Shu-Ni
authors.initials: SN
authors.lastname: Li
authors.affiliation: Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi, 710062, P. R. China.
authors.forename: Yu-Cheng
authors.initials: YC
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi, 710062, P. R. China.
authors.forename: Quan-Guo
authors.identifier: http://orcid.org/0000-0003-1117-4017
authors.initials: QG
authors.lastname: Zhai
keywords: C2-hydrocarbons/CH4 selectivity; Fe3-trimer; gas uptake; metal-organic frameworks; tetratopic carboxylate ligand