Expanded sodalite-type metal-organic frameworks:: Increased stability and H2 adsorption through ligand-directed catenation

The torsion between the central benzene ring and the outer aromatic rings in 1, 3,5-tri-p-(tetrazol-5-yl) phenyl benzene (H3TPB-3tz) and the absence of such strain in 2,4,6-tri-p-(tetrazol-5-yl)phenyl-s-triazine (H3TPT-3tz) are shown to allow the selective synthesis of noncatenated and catenated versions of expanded socalite-type metal-organic frameworks. The reaction of H3TPB-3tz with CuCl2-2H(2)O affords the noncatenated compound Cu-3[(Cu4Cl)(3)(TPB-3tz)(8)](2)center dot 11CuCl(2)center dot 8H(2)O 120DMF (2), while the reaction of H3TPT-3tz with MnCl2 center dot 4H(2)O or CuCl2 center dot 2H(2)O generates the catenated compounds Mn-3[(Mn4Cl)(3)(TPT-3tz)(8)](2)-25H(2)O center dot 15CH(3)OH center dot 95DMF (3) and Cu-3[(Cu4Cl)(3)(TPT-3tz)(8)](2)center dot xsolvent (4). Significantly, catenation helps to stabilize the framework toward collapse upon desolvation, leading to an increase in the surface area from 1120 to 1580 m(2) /g and an increase in the hydrogen storage capacity from 2.8 to 3.7 excess wt % at 77 K for 2 and 3, respectively. The total hydrogen uptake in desolvated 3 reaches 4.5 wt % and 37 g/L at 80 bar and 77 K, demonstrating that control of catenation can be an important factor in the generation of hydrogen storage materials.