UTSA-74: A MOF-74 Isomer with Two Accessible Binding Sites per Metal Center for Highly Selective Gas Separation.
A new metal-organic framework Zn2(H2O)(dobdc)·0.5(H2O) (UTSA-74, H4dobdc = 2,5-dioxido-1,4-benzenedicarboxylic acid), Zn-MOF-74/CPO-27-Zn isomer, has been synthesized and structurally characterized. It has a novel four coordinated fgl topology with one-dimensional channels of about 8.0 Å. Unlike metal sites in the well-established MOF-74 with a rod-packing structure in which each of them is in a five coordinate square pyramidal coordination geometry, there are two different Zn(2+) sites within the binuclear secondary building units in UTSA-74 in which one of them (Zn1) is in a tetrahedral while another (Zn2) in an octahedral coordination geometry. After activation, the two axial water molecules on Zn2 sites can be removed, generating UTSA-74a with two accessible gas binding sites per Zn2 ion. Accordingly, UTSA-74a takes up a moderately high and comparable amount of acetylene (145 cm(3)/cm(3)) to Zn-MOF-74. Interestingly, the accessible Zn(2+) sites in UTSA-74a are bridged by carbon dioxide molecules instead of being terminally bound in Zn-MOF-74, so UTSA-74a adsorbs a much smaller amount of carbon dioxide (90 cm(3)/cm(3)) than Zn-MOF-74 (146 cm(3)/cm(3)) at room temperature and 1 bar, leading to a superior MOF material for highly selective C2H2/CO2 separation. X-ray crystal structures, gas sorption isotherms, molecular modeling, and simulated and experimental breakthroughs comprehensively support this result.
School of Biology, Chemistry and Material Science, East China University of Technology , Fuzhou, Jiangxi 344000, China.
Feng
F
Luo
School of Biology, Chemistry and Material Science, East China University of Technology , Fuzhou, Jiangxi 344000, China.
Changsheng
C
Yan
School of Biology, Chemistry and Material Science, East China University of Technology , Fuzhou, Jiangxi 344000, China.
Lilong
L
Dang
Van't Hoff Institute for Molecular Sciences, University of Amsterdam , Science Park 904, 1098 XH Amsterdam, The Netherlands.
Rajamani
R
Krishna
Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg, Maryland 20899-6102, United States.
Wei
W
Zhou
Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg, Maryland 20899-6102, United States.
Hui
H
Wu
Advanced Membranes and Porous Materials Center, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology , Thuwal 23955-6900, Saudi Arabia.
Xinglong
X
Dong
Advanced Membranes and Porous Materials Center, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology , Thuwal 23955-6900, Saudi Arabia.
Yu
Y
Han
School of Materials Science and Engineering, National Institute for Advanced Materials, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University , Tianjin 300071, China.
Tong-Liang
TL
Hu
School of Molecular Sciences, Arizona State University , Tempe, Arizona 85287, United States.
Michael
M
O'Keeffe
School of Biology, Chemistry and Material Science, East China University of Technology , Fuzhou, Jiangxi 344000, China.
Lingling
L
Wang
School of Biology, Chemistry and Material Science, East China University of Technology , Fuzhou, Jiangxi 344000, China.
Mingbiao
M
Luo
Department of Chemistry, University of Texas at San Antonio , One UTSA Circle, San Antonio, Texas 78249-0698, United States.
Rui-Biao
RB
Lin
Department of Chemistry, University of Texas at San Antonio , One UTSA Circle, San Antonio, Texas 78249-0698, United States.
Banglin
B
Chen