Expanded Sodalite-Type Metal−Organic Frameworks:  Increased Stability and H₂ Adsorption through Ligand-Directed Catenation

Abstract

The torsion between the central benzene ring and the outer aromatic rings in 1,3,5-tri-p-(tetrazol-5-yl)phenylbenzene (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 sodalite-type metal-organic frameworks. The reaction of H3TPB-3tz with CuCl2.2H2O affords the noncatenated compound Cu3[(Cu4Cl)3(TPB-3tz)8]2.11CuCl2.8H2O.120DMF (2), while the reaction of H3TPT-3tz with MnCl2.4H2O or CuCl2.2H2O generates the catenated compounds Mn3[(Mn4Cl)3(TPT-3tz)8]2.25H2O.15CH3OH.95DMF (3) and Cu3[(Cu4Cl)3(TPT-3tz)8]2.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 m2/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.

On the Nature of the Adsorbed Hydrogen Phase in Microporous Metal−Organic Frameworks at Supercritical Temperatures

“…28 We also have examined microporous coordination solids analogous to the MOFs where carboxylate ligands are replaced by structurally analogous functional nitrogen-based bridging ligands while essentially keeping the same specific surface area. The linking organic units are BDP (1,4-benzenedipyrazolate), BTT (1,3,5-benzenetristetrazolate), 29 TPT-3tz (2,4,6-tri-p(tetrazol-5-yl)phenyl-s-triazine), 30 and TTPM (tetrakis (4-tetrazolylphenyl) methane). 31 Finally we explored two MOFs based on metal imidazolates: PhIM (benzimidazolate) and MeIM (2-methylimidazolate).…”

Mixed‐Ligand Metal–Organic Frameworks with Large Pores: Gas Sorption Properties and Single‐Crystal‐to‐Single‐Crystal Transformation on Guest Exchange

“…[ 45] On exposure of the sample to air for three days, the H 2 adsorption capacity was reduced even after the reactivation (162 cm 3 g…”

Hydrogen Adsorption on Metal Organic Framework Materials for Storage Applications

“…It is evident that there are correlations between the hydrogen uptakes at high pressure and the porous structure parameters for the porous MOF materials. The correlation for hydrogen high pressure uptake for MOFs with BET surface area is also observed for other porous materials with Types I and H2MOfWt Figure 4.8 The variation of H 2 adsorbed (wt%) at saturation at 77 K with Langmuir surface area (m 2 g À1 ) for porous MOF materials [21,27,37,39,46,51,54,57,60,119,127,134,136,[145][146][147]150,153,[160][161][162]165,[167][168][169]173,186,187] II nitrogen adsorption isotherms and therefore, the correlation is more general (see Figure 4.9). Figure 4.10 also shows a comparison of the hydrogen uptake data at or close to saturation with total pore volume and the line corresponding to liquid hydrogen filling the pores.…”

“…Figure 4.10 also shows a comparison of the hydrogen uptake data at or close to saturation with total pore volume and the line corresponding to liquid hydrogen filling the pores. The The variation of H 2 adsorbed (wt%) at saturation at 77 K with BET surface area (m 2 g À1 ) for porous MOF materials, [21,[36][37][38][39]41,46,50,51,54,57,60,127,[134][135][136][137][145][146][147]150,158,159,[162][163][164][165][166]168,173,186,187] carbons, [68,78,80,[83][84][85][86][87] boron doped carbon, [191] MCM-41, [90] zeolites, [92,93] polymers [98,100,104,<...>…”