National Institute of Standards and Technology, Center for Neutron Research, Gaithersburg, MD 20899, USA.
Dalton Trans. 2012 Apr 14;41(14):4180-7. doi: 10.1039/c2dt12138g. Epub 2012 Feb 28.
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.
采用多种互补技术，包括低压气体吸附、中子粉末衍射和非弹性中子散射，研究了 Fe(2)(dobdc)(dobdc(4-) = 2,5-二氧代-1,4-苯二甲酸根)和氧化类似物 Fe(2)(O(2))(dobdc)的储氢性能。这两种具有一维六方通道且通道表面装饰有不饱和铁配位位点的金属-有机骨架，分别表现出 9.7(1)kJ/mol 和 10.0(1)kJ/mol 的初始等吸附热。中子粉末衍射可以在两个骨架中识别出三个 D(2)结合位点，最近的接触分别对应于 Fe-D(2)分离距离为 2.47(3)和 2.53(5)Å。从吸附在 Fe(2)(dobdc)中的 p-H(2)(仲氢)和 D(2)-p-H(2)混合物中获得的非弹性中子散射光谱，揭示了两个相邻吸附位点之间的弱相互作用，这一发现与先前关于相邻 H(2)分子之间可能存在“配对”的报道相反。
