Hydrogen Storage in a Microporous Metal-Organic Framework with Exposed Mn~(2+) Coordination Sites

摘要

Use of the tritopic bridging ligand 1,3,5-benzenetristetrazolate (BTT~(3-)) enables formation of [Mn-(DMF)_6]_3[(Mn_4CI)_3(BTT)_8(H_2O)_(12)]_2 centre dot 42DMF centre dot 11H_2O centre dot 20CH_3OH,featuring a porous metal-organic framework with a previously unknown cubic topology.Crystals of the compound remain intact upon desolvation and show a total H_2 uptake of 6.9 wt % at 77 K and 90 bar,which at 60 g H_2/L provides a storage density 85% of that of liquid hydrogen.The material exhibits a maximum isosteric heat of adsorption of 10.1 kJ/mol,the highest yet observed for a metal-organic framework.Neutron powder diffraction data demonstrate that this is directly related to H_2 binding at coordinatively unsaturated Mn~(2+) centers within the framework.