M2(m-dobdc) (M=Mg,Mn, Fe, Co, Ni) Metal-Organic Frameworks Exhibiting Increased Charge Density and Enhanced H2 Binding at the Open Metal Sites

Published

August 14, 2014

Author(s)

Matthew T. Kapelewski, Stephen J. Geier, Matthew Ross Hudson, David Stuck, Jarad A. Mason, Jocienne N. Nelson, Zeric Z. Hulvey, Elizabeth Gilmour, Stephen A. FitzGerald, Martin Head-Gordon, Craig Brown, Jeffrey R. Long

Abstract

Metal-organic frameworks are a class of microporous materials that are being heavily investigated for their hydrogen storage properties due to their high internal surface areas and strong interactions with adsorbed gases. Increasing they hydrogen binding enthalpy of such materials is necessary for them to be viable candidates for use as hydrogen storage media in most applications. A structural isomer of the well-known M₂(dobdc) (dobdc = 2,5-dioxido-1,4-benzenedicarboxylate), termed M₂(m-dobdc)(mdobdc)= 4,6-dioxido-1.3-benzenedicarboxylate), has been synthesized and its hydrogen storage properties investigated. The regioisomeric linker yields a framework with a modified geometry and altered electronics around the open metal coordination sites in the framework, which leads to increased hydrogen binding enthalpies for several metals (Mn^{2+, Fe}u2+, and Co^u2+). A variety of techniques, including powder x-ray diffraction, neutron diffraction, inelastic neutron scattering, infrared spectroscopy, and DFT calculations were used to elucidate how these subtle structural and electronic difference lead to significantly increased H₂ binding enthalpies as compared with M₂(dobdc). These increases in binding enthalpy from a slight linker modification highlight the importance of how minor changes can have a significant impact on the properties and electronics of metal-organic frameworks for specific applications.

Citation

Journal of the American Chemical Society

Volume

136

Pub Type

Journals

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Keywords

hydrogen storage, metal-organic frameworks, structure determination, powder diffraction

Citation

Kapelewski, M. , Geier, S. , Hudson, M. , Stuck, D. , Mason, J. , Nelson, J. , Hulvey, Z. , Gilmour, E. , FitzGerald, S. , Head-Gordon, M. , Brown, C. and Long, J. (2014), M₂(m-dobdc) (M=Mg,Mn, Fe, Co, Ni) Metal-Organic Frameworks Exhibiting Increased Charge Density and Enhanced H₂ Binding at the Open Metal Sites, Journal of the American Chemical Society, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=914953 (Accessed December 12, 2024)