Strong H(2) binding and selective gas adsorption within the microporous coordination solid Mg(3)(O(2)C-C(10)H(6)-CO(2))(3).
The synthesis of Mg3(NDC)3(DEF)4 (NDC = 2,6-naphthalenedicarboxylate, DEF = N,N-diethylformamide, 1), the first porous metal-organic framework solid incorporating Mg2+ ions, is reported. Its structure consists of linear Mg3 units linked via NDC bridges to form a three-dimensional framework, featuring one-dimensional channels filled with DEF molecules. Significantly, its framework is fully analogous to that observed within Zn3(NDC)3(CH3OH)2.2DMF.H2O (2), demonstrating that Mg2+ ions can directly substitute for the heavier Zn2+ ions. Compound 1 is readily desolvated by heating at 190 degrees C to give the microporous solid Mg3(NDC)3, exhibiting a BET surface area of 190 m2/g. Adsorption isotherms measured at 77 and 87 K indicate high H2 adsorption enthalpies in the range 7.0-9.5 kJ/mol, depending on the degree of loading. In addition, the material displays selective adsorption of H2 or O2 over N2 or CO, suggesting possible applications in gas separation technologies.
Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
Mircea
M
Dinca
Jeffrey R
JR
Long