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Title: Enhancement of CO 2 Uptake and Selectivity in a Metal–Organic Framework by the Incorporation of Thiophene Functionality

The complex [Zn 2(tdc) 2dabco] (H 2tdc = thiophene-2,5-dicarboxylic acid; dabco = 1,4-diazabicyclooctane) shows a remarkable increase in carbon dioxide (CO 2) uptake and CO 2/dinitrogen (N 2) selectivity compared to the nonthiophene analogue [Zn 2(bdc) 2dabco] (H 2bdc = benzene-1,4-dicarboxylic acid; terephthalic acid). CO 2 adsorption at 1 bar for [Zn 2(tdc) 2dabco] is 67.4 cm 3·g -1(13.2 wt %) at 298 K and 153 cm 3·g -1(30.0 wt %) at 273 K. For [Zn 2(bdc) 2dabco], the equivalent values are 46 cm 3·g -1(9.0 wt %) and 122 cm 3·g -1(23.9 wt %), respectively. The isosteric heat of adsorption for CO 2 in [Zn 2(tdc) 2dabco] at zero coverage is low (23.65 kJ·mol -1), ensuring facile regeneration of the porous material. Enhancement by the thiophene group on the separation of CO 2/N 2 gas mixtures has been confirmed by both ideal adsorbate solution theory calculations and dynamic breakthrough experiments. The preferred binding sites of adsorbed CO 2 in [Zn 2(tdc) 2dabco] have been unambiguously determined by in situ single-crystal diffraction studies on CO 2-loaded [Zn 2(tdc) 2dabco], coupled with quantum-chemical calculations. These studies unveil the role of the thiophene moieties in the specific CO 2 binding via anmore » induced dipole interaction between CO 2 and the sulfur center, confirming that an enhanced CO 2 capacity in [Zn 2(tdc) 2dabco] is achieved without the presence of open metal sites. The experimental data and theoretical insight suggest a viable strategy for improvement of the adsorption properties of already known materials through the incorporation of sulfur-based heterocycles within their porous structures.« less
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [3] ;  [3] ; ORCiD logo [4] ;  [4] ;  [3] ;  [5] ;  [6] ; ORCiD logo [6] ;  [2] ;  [2] ; ORCiD logo [7]
  1. Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)
  2. Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation); Novosibirsk State Univ., Novosibirsk (Russian Federation)
  3. Univ. of Manchester, Manchester (United Kingdom)
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  5. Univ. of Bath, Bath (United Kingdom); Univ. of Nottingham, Nottingham (United Kingdom)
  6. Univ. of Nottingham, Nottingham (United Kingdom)
  7. Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation); Univ. of Manchester, Manchester (United Kingdom)
Publication Date:
Grant/Contract Number:
AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Inorganic Chemistry
Additional Journal Information:
Journal Volume: 57; Journal Issue: 9; Related Information: © 2018 American Chemical Society.; Journal ID: ISSN 0020-1669
Publisher:
American Chemical Society (ACS)
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Carbon dioxide; metal-organic framework; thiophene; carboxylate; zinc; binding site; breakthrough
OSTI Identifier:
1460318