Hydrogen adsorption in the metal–organic frameworks Fe2(dobdc) and Fe2(O2)(dobdc)

Wendy L. Queen; Eric D. Bloch; Craig M. Brown; Matthew R. Hudson; Jarad A. Mason; Leslie J. Murray; Anibal Javier Ramirez-Cuesta; Vanessa K. Peterson; Jeffrey R. Long

doi:10.1039/C2DT12138G

Hydrogen adsorption in the metal–organic frameworks Fe₂(dobdc) and Fe₂(O₂)(dobdc)†

Wendy L. Queen,^ab Eric D. Bloch,^b Craig M. Brown,*^ac Matthew R. Hudson,^ad Jarad A. Mason,^b Leslie J. Murray,^be Anibal Javier Ramirez-Cuesta,^f Vanessa K. Peterson^c and Jeffrey R. Long*^b

Author affiliations

* Corresponding authors

^a National Institute of Standards and Technology, Center for Neutron Research, Gaithersburg, MD, USA
E-mail: craig.brown@nist.gov

^b Department of Chemistry, University of California, Berkeley and Division of Materials Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
E-mail: jrlong@berkeley.edu
Tel: +5106420860

^c The Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia

^d Department of Materials Science and Engineering, University of Maryland, College Park, MD, USA

^e Department of Chemistry, University of Florida, Gainesville, FL, USA

^f ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, UK

Abstract

The hydrogen storage properties of Fe₂(dobdc) (dobdc⁴⁻ = 2,5-dioxido-1,4-benzenedicarboxylate) and an oxidized analog, Fe₂(O₂)(dobdc), have been examined using several complementary techniques, including low-pressure gas adsorption, neutron powder diffraction, and inelastic neutron scattering. These two metal–organic frameworks, which possess one-dimensional hexagonal channels decorated with unsaturated iron coordination sites, exhibit high initial isosteric heats of adsorption of −9.7(1) and −10.0(1) kJ mol⁻¹, respectively. Neutron powder diffraction has allowed the identification of three D₂ binding sites within the two frameworks, with the closest contacts corresponding to Fe–D₂ separations of 2.47(3) and 2.53(5) Å, respectively. Inelastic neutron scattering spectra, obtained from p-H₂ (para-H₂) and D₂–p-H₂ mixtures adsorbed in Fe₂(dobdc), reveal weak interactions between two neighboring adsorption sites, a finding that is in opposition to a previous report of possible ‘pairing’ between neighboring H₂ molecules.

This article is part of the themed collection: Coordination chemistry in the solid state

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Article information

DOI: https://doi.org/10.1039/C2DT12138G
Article type: Paper
Submitted: 08 Nov 2011
Accepted: 11 Jan 2012
First published: 28 Feb 2012

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Dalton Trans., 2012,41, 4180-4187

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Hydrogen adsorption in the metal–organic frameworks Fe₂(dobdc) and Fe₂(O₂)(dobdc)

W. L. Queen, E. D. Bloch, C. M. Brown, M. R. Hudson, J. A. Mason, L. J. Murray, A. J. Ramirez-Cuesta, V. K. Peterson and J. R. Long, Dalton Trans., 2012, 41, 4180 DOI: 10.1039/C2DT12138G

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