Microporous Metal–Organic Framework with Lantern-like Dodecanuclear Metal Coordination Cages as Nodes for Selective Adsorption of C₂/C₁ Mixtures and Sensing of Nitrobenzene

A microporous metal–organic framework (<b>FJU-12</b>), {[Cd₁₂(Trz)₈(DMF)₂(H₂O)₄]­(BDC)₉}·2­(Me₂NH₂)·4DMF·16H₂O (Trz = 1,2,4-triazole, BDC = terephthalic acid, DMF = <i>N</i>,<i>N</i>-dimethylformamide), was rationally constructed using unprecedented lantern-like 1,2,4-triazole-based dodecanuclear metal coordination cages as supermolecular building blocks. After activation, <b>FJU-12a</b> exhibits highly selective adsorption of C₂ compound/CH₄ mixtures and efficient sensing of nitrobenzene (NB). The selectivity (79.7) of C₂H₂/CH₄ is comparable to the most selective Cu-TDPAT (82, TDPAT = 2,4,6-tris­(3,5-dicarboxylphenylamino)-1,3,5-triazine)

Microporous Metal–Organic Framework Stabilized by Balanced Multiple Host–Couteranion Hydrogen-Bonding Interactions for High-Density CO₂ Capture at Ambient Conditions

Microporous metal organic frameworks (MOFs) show promising application in several fields, but they often suffer from the weak robustness and stability after the removal of guest molecules. Here, three isostructural cationic metal–organic frameworks {[(Cu₄Cl)­(cpt)₄(H₂O)₄]·3X·4DMAc·CH₃OH·5H₂O} (<b>FJU-14</b>, X = NO₃, ClO_4, BF₄; DMAc = <i>N</i>,<i>N</i>′-dimethylacetamide) containing two types of polyhedral nanocages, one octahedron, and another tetrahedron have been synthesized from bifunctional organic ligands 4-(4<i>H</i>-1,2,4-triazol-4-yl) benzoic acid (Hcpt) and various copper salts. The series of MOFs <b>FJU-14</b> are demonstrated as the first examples of the isostructural MOFs whose robustness, thermal stability, and CO₂ capacity can be greatly improved via rational modulation of counteranions in the tetrahedral cages. The activated <b>FJU-14-BF</b>_<b>4</b><b>-a</b> containing BF₄^– anion can take CO₂ of 95.8 cm³ cm^–3 at ambient conditions with an adsorption enthalpy only of 18.8 kJ mol^–1. The trapped CO₂ density of 0.955 g cm^–3 is the highest value among the reported MOFs. Dynamic fixed bed breakthrough experiments indicate that the separation of CO₂/N₂ mixture gases through a column packed with <b>FJU-14-BF</b>_<b>4</b><b>-a</b> solid can be efficiently achieved. The improved robustness and thermal stability for <b>FJU-14-BF</b>_<b>4</b><b>-a</b> can be attributed to the balanced multiple hydrogen-bonding interactions (MHBIs) between the BF₄^– counteranion and the cationic skeleton, while the high-density and low-enthalpy CO₂ capture on <b>FJU-14-BF</b>_<b>4</b><b>-a</b> can be assigned to the multiple-point interactions between the adsorbate molecules and the framework as well as with its counteranions, as proved by single-crystal structures of the guest-free and CO₂-loaded <b>FJU-14-BF</b>_<b>4</b><b>-a</b> samples

Microporous Metal–Organic Framework Stabilized by Balanced Multiple Host–Couteranion Hydrogen-Bonding Interactions for High-Density CO₂ Capture at Ambient Conditions

Microporous metal organic frameworks (MOFs) show promising application in several fields, but they often suffer from the weak robustness and stability after the removal of guest molecules. Here, three isostructural cationic metal–organic frameworks {[(Cu₄Cl)­(cpt)₄(H₂O)₄]·3X·4DMAc·CH₃OH·5H₂O} (<b>FJU-14</b>, X = NO₃, ClO_4, BF₄; DMAc = <i>N</i>,<i>N</i>′-dimethylacetamide) containing two types of polyhedral nanocages, one octahedron, and another tetrahedron have been synthesized from bifunctional organic ligands 4-(4<i>H</i>-1,2,4-triazol-4-yl) benzoic acid (Hcpt) and various copper salts. The series of MOFs <b>FJU-14</b> are demonstrated as the first examples of the isostructural MOFs whose robustness, thermal stability, and CO₂ capacity can be greatly improved via rational modulation of counteranions in the tetrahedral cages. The activated <b>FJU-14-BF</b>_<b>4</b><b>-a</b> containing BF₄^– anion can take CO₂ of 95.8 cm³ cm^–3 at ambient conditions with an adsorption enthalpy only of 18.8 kJ mol^–1. The trapped CO₂ density of 0.955 g cm^–3 is the highest value among the reported MOFs. Dynamic fixed bed breakthrough experiments indicate that the separation of CO₂/N₂ mixture gases through a column packed with <b>FJU-14-BF</b>_<b>4</b><b>-a</b> solid can be efficiently achieved. The improved robustness and thermal stability for <b>FJU-14-BF</b>_<b>4</b><b>-a</b> can be attributed to the balanced multiple hydrogen-bonding interactions (MHBIs) between the BF₄^– counteranion and the cationic skeleton, while the high-density and low-enthalpy CO₂ capture on <b>FJU-14-BF</b>_<b>4</b><b>-a</b> can be assigned to the multiple-point interactions between the adsorbate molecules and the framework as well as with its counteranions, as proved by single-crystal structures of the guest-free and CO₂-loaded <b>FJU-14-BF</b>_<b>4</b><b>-a</b> samples

40-Fold Enhanced Intrinsic Proton Conductivity in Coordination Polymers with the Same Proton-Conducting Pathway by Tuning Metal Cation Nodes

Three isostructural imidazole-cation-templated metal phosphates (<b>FJU-25</b>) are the first examples to demonstrate that the tuning of metal cation nodes can be an efficient strategy to significantly improve the proton conductivity without changing the structure of the proton-conducting pathway

High Anhydrous Proton Conductivity of Imidazole-Loaded Mesoporous Polyimides over a Wide Range from Subzero to Moderate Temperature

On-board fuel cell technology requires proton conducting materials with high conductivity not only at intermediate temperatures for work but also at room temperature and even at subzero temperature for startup when exposed to the colder climate. To develop such materials is still challenging because many promising candidates for the proton transport on the basis of extended microstructures of water molecules suffer from significant damage by heat at temperatures above 80 °C or by freeze below −5 °C. Here we show imidazole loaded tetrahedral polyimides with mesopores and good stability (Im@Td-PNDI <b>1</b> and Im@Td-PPI <b>2</b>) exhibiting a high anhydrous proton conductivity over a wide temperature range from −40 to 90 °C. Among all anhydrous proton conductors, the conductivity of <b>2</b> is the highest at temperatures below 40 °C and comparable with the best materials, His@[Al­(OH)­(1,4-ndc)]_<i>n</i> and [Zn₃(H₂PO₄)₆(H₂O)₃]­(Hbim), above 40 °C