Water-Stable In(III)-Based Metal-Organic Frameworks with Rod-Shaped Secondary Building Units: Single-Crystal to Single-Crystal Transformation and Selective Sorption of C2H2over CO2and CH4.
Three new water-stable In(III)-based metal-organic frameworks, namely, [In3(TTTA)2(OH)3(H2O)]·(DMA)3(BUT-70, DMA = N,N-dimethylacetamide), [In3(TTTA)2(CH3O)3] (BUT-70A), and [In3(TTTA)2(OH)3] (BUT-70B), with rod-shaped secondary building units (SBUs) and an new acrylate-based ligand, (2E,2'E,2″E)-3,3',3″-(2,4,6-trimethylbenzene-1,3,5-triyl)-triacrylate (TTTA3-) were obtained and structurally characterized. BUT-70A and -70B were generated in a single-crystal to single-crystal transformation fashion from BUT-70 through guest exchange followed by their removal. The solvents used for guest exchange were methanol and dichloromethane, respectively. Single-crystal structure analyses show that the guest exchange and removal process is accompanied by the substitution of coordinated water molecules of In(III) centers with uncoordinated carboxylate O atoms of TTTA3-ligands. Moreover, hydroxyl groups bridging two In(III) centers are also replaced by methoxyl groups in the transformation from BUT-70 to -70A. Overall, three metal-organic frameworks (MOFs) are constructed by infinite chains consisting of corner-sharing InO4(OR)2(R = H or Me) octahedral entities, which are interconnected by TTTA3-ligands to form three-dimensional frameworks. Unlike most reported MOFs with infinite chains as SBUs, such as well-known MIL-53 and M-MOF-74, which have one-dimensional channels along the chain direction, the BUT-70 series contain two-dimensional intersecting channels. The Brunauer-Emmett-Teller surface area and pore volume of BUT-70A were estimated to be 460 m2g-1and 0.18 cm3g-1, respectively, which are obviously lower than those of BUT-70B (695 m2g-1and 0.29 cm3g-1). Gas adsorption experiments demonstrated that BUT-70A and -70B are able to selectively adsorb C2H2over CO2and CH4. At 1 atm and 298 K, BUT-70A uptakes 3.1 mmol g-1C2H2, which is 3.6 times that of the CO2uptake and 7.2 times that of the CH4uptake. Compared with BUT-70A, BUT-70B presents an even higher C2H2uptake of 3.9 mmol g-1at the same conditions, but slightly lower Ideal Adsorbed Solution Theory C2H2/CO2and C2H2/CH4selectivities.
Institute of Circular Economy, Beijing University of Technology , Beijing 100124, P. R. China.|Beijing Key Laboratory for Green Catalysis and Separation and Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology , Beijing 100124, P. R. China.
Zhen-Ji
ZJ
Guo
Institute of Circular Economy, Beijing University of Technology , Beijing 100124, P. R. China.
Jiamei
J
Yu
Beijing Key Laboratory for Green Catalysis and Separation and Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology , Beijing 100124, P. R. China.
Yong-Zheng
YZ
Zhang
Beijing Key Laboratory for Green Catalysis and Separation and Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology , Beijing 100124, P. R. China.
Jian
J
Zhang
Beijing Key Laboratory for Green Catalysis and Separation and Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology , Beijing 100124, P. R. China.
Ya
http://orcid.org/0000-0001-8477-1328
Y
Chen
Institute of Circular Economy, Beijing University of Technology , Beijing 100124, P. R. China.
Yufeng
Y
Wu
Beijing Key Laboratory for Green Catalysis and Separation and Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology , Beijing 100124, P. R. China.
Lin-Hua
http://orcid.org/0000-0003-0017-3887
LH
Xie
Beijing Key Laboratory for Green Catalysis and Separation and Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology , Beijing 100124, P. R. China.
Jian-Rong
http://orcid.org/0000-0002-8101-8493
JR
Li