title: Hydrogen adsorption in the metal-organic frameworks Fe2(dobdc) and Fe2(O2)(dobdc).
abstract: The hydrogen storage properties of Fe(2)(dobdc) (dobdc(4-) = 2,5-dioxido-1,4-benzenedicarboxylate) and an oxidized analog, Fe(2)(O(2))(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 D(2) binding sites within the two frameworks, with the closest contacts corresponding to Fe-D(2) separations of 2.47(3) and 2.53(5) Å, respectively. Inelastic neutron scattering spectra, obtained from p-H(2) (para-H(2)) and D(2)-p-H(2) mixtures adsorbed in Fe(2)(dobdc), reveal weak interactions between two neighboring adsorption sites, a finding that is in opposition to a previous report of possible 'pairing' between neighboring H(2) molecules.
authors.affiliation: National Institute of Standards and Technology, Center for Neutron Research, Gaithersburg, MD 20899, USA.
authors.forename: Wendy L
authors.initials: WL
authors.lastname: Queen
authors.forename: Eric D
authors.initials: ED
authors.lastname: Bloch
authors.forename: Craig M
authors.initials: CM
authors.lastname: Brown
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Hudson
authors.forename: Jarad A
authors.initials: JA
authors.lastname: Mason
authors.forename: Leslie J
authors.initials: LJ
authors.lastname: Murray
authors.forename: Anibal Javier
authors.initials: AJ
authors.lastname: Ramirez-Cuesta
authors.forename: Vanessa K
authors.initials: VK
authors.lastname: Peterson
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Long