TY - JOUR
T1 - Reversible CO binding enables tunable CO/H2 and CO/N2 separations in metal-organic frameworks with exposed divalent metal cations
AU - Bloch, Eric D.
AU - Hudson, Matthew R.
AU - Mason, Jarad A.
AU - Chavan, Sachin
AU - Crocellà, Valentina
AU - Howe, Joshua D.
AU - Lee, Kyuho
AU - Dzubak, Allison L.
AU - Queen, Wendy L.
AU - Zadrozny, Joseph M.
AU - Geier, Stephen J.
AU - Lin, Li Chiang
AU - Gagliardi, Laura
AU - Smit, Berend
AU - Neaton, Jeffrey B.
AU - Bordiga, Silvia
AU - Brown, Craig M.
AU - Long, Jeffrey R.
N1 - Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 2014/7/30
Y1 - 2014/7/30
N2 - Six metal-organic frameworks of the M2(dobdc) (M = Mg, Mn, Fe, Co, Ni, Zn; dobdc4- = 2,5-dioxido-1,4-benzenedicarboxylate) structure type are demonstrated to bind carbon monoxide reversibly and at high capacity. Infrared spectra indicate that, upon coordination of CO to the divalent metal cations lining the pores within these frameworks, the C-O stretching frequency is blue-shifted, consistent with nonclassical metal-CO interactions. Structure determinations reveal M-CO distances ranging from 2.09(2) Å for M = Ni to 2.49(1) Å for M = Zn and M-C-O angles ranging from 161.2(7)° for M = Mg to 176.9(6)° for M = Fe. Electronic structure calculations employing density functional theory (DFT) resulted in good agreement with the trends apparent in the infrared spectra and crystal structures. These results represent the first crystallographically characterized magnesium and zinc carbonyl compounds and the first high-spin manganese(II), iron(II), cobalt(II), and nickel(II) carbonyl species. Adsorption isotherms indicate reversible adsorption, with capacities for the Fe, Co, and Ni frameworks approaching one CO per metal cation site at 1 bar, corresponding to loadings as high as 6.0 mmol/g and 157 cm3/cm3. The six frameworks display (negative) isosteric heats of CO adsorption ranging from 52.7 to 27.2 kJ/mol along the series Ni > Co > Fe > Mg > Mn > Zn, following the Irving-Williams stability order. The reversible CO binding suggests that these frameworks may be of utility for the separation of CO from various industrial gas mixtures, including CO/H2 and CO/N2. Selectivities determined from gas adsorption isotherm data using ideal adsorbed solution theory (IAST) over a range of gas compositions at 1 bar and 298 K indicate that all six M2(dobdc) frameworks could potentially be used as solid adsorbents to replace current cryogenic distillation technologies, with the choice of M dictating adsorbent regeneration energy and the level of purity of the resulting gases.
AB - Six metal-organic frameworks of the M2(dobdc) (M = Mg, Mn, Fe, Co, Ni, Zn; dobdc4- = 2,5-dioxido-1,4-benzenedicarboxylate) structure type are demonstrated to bind carbon monoxide reversibly and at high capacity. Infrared spectra indicate that, upon coordination of CO to the divalent metal cations lining the pores within these frameworks, the C-O stretching frequency is blue-shifted, consistent with nonclassical metal-CO interactions. Structure determinations reveal M-CO distances ranging from 2.09(2) Å for M = Ni to 2.49(1) Å for M = Zn and M-C-O angles ranging from 161.2(7)° for M = Mg to 176.9(6)° for M = Fe. Electronic structure calculations employing density functional theory (DFT) resulted in good agreement with the trends apparent in the infrared spectra and crystal structures. These results represent the first crystallographically characterized magnesium and zinc carbonyl compounds and the first high-spin manganese(II), iron(II), cobalt(II), and nickel(II) carbonyl species. Adsorption isotherms indicate reversible adsorption, with capacities for the Fe, Co, and Ni frameworks approaching one CO per metal cation site at 1 bar, corresponding to loadings as high as 6.0 mmol/g and 157 cm3/cm3. The six frameworks display (negative) isosteric heats of CO adsorption ranging from 52.7 to 27.2 kJ/mol along the series Ni > Co > Fe > Mg > Mn > Zn, following the Irving-Williams stability order. The reversible CO binding suggests that these frameworks may be of utility for the separation of CO from various industrial gas mixtures, including CO/H2 and CO/N2. Selectivities determined from gas adsorption isotherm data using ideal adsorbed solution theory (IAST) over a range of gas compositions at 1 bar and 298 K indicate that all six M2(dobdc) frameworks could potentially be used as solid adsorbents to replace current cryogenic distillation technologies, with the choice of M dictating adsorbent regeneration energy and the level of purity of the resulting gases.
UR - http://www.scopus.com/inward/record.url?scp=84905251111&partnerID=8YFLogxK
U2 - 10.1021/ja505318p
DO - 10.1021/ja505318p
M3 - Article
AN - SCOPUS:84905251111
VL - 136
SP - 10752
EP - 10761
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 30
ER -