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Halogen–C 2 H 2 Binding in Ultramicroporous Metal–Organic Frameworks (MOFs) for Benchmark C 2 H 2 /CO 2 Separation Selectivity
Author(s) -
Mukherjee Soumya,
He Yonghe,
Franz Douglas,
Wang ShiQiang,
Xian WanRu,
Bezrukov Andrey A.,
Space Brian,
Xu Zhengtao,
He Jun,
Zaworotko Michael J.
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202000008
Subject(s) - isostructural , chemistry , binding energy , selectivity , halogen , metal organic framework , diamondoid , inorganic chemistry , molecule , crystallography , catalysis , adsorption , crystal structure , organic chemistry , physics , alkyl , nuclear physics
Acetylene (C 2 H 2 ) capture is a step in a number of industrial processes, but it comes with a high‐energy footprint. Although physisorbents have the potential to reduce this energy footprint, they are handicapped by generally poor selectivity versus other relevant gases, such as CO 2 and C 2 H 4 . In the case of CO 2 , the respective physicochemical properties are so similar that traditional physisorbents, such as zeolites, silica, and activated carbons cannot differentiate well between CO 2 and C 2 H 2 . Herein, we report that a family of three isostructural, ultramicroporous (<7 Å) diamondoid metal–organic frameworks, [Cu(TMBP)X] (TMBP=3,3′,5,5′‐tetramethyl‐4,4′‐bipyrazole), TCuX (X=Cl, Br, I), offer new benchmark C 2 H 2 /CO 2 separation selectivity at ambient temperature and pressure. We attribute this performance to a new type of strong binding site for C 2 H 2 . Specifically, halogen ⋅⋅⋅ HC interactions coupled with other noncovalent in a tight binding site is C 2 H 2 specific versus CO 2 . The binding site is distinct from those found in previous benchmark sorbents, which are based on open metal sites or electrostatic interactions enabled by inorganic fluoro or oxo anions.