Enhancing Effect of Fullerene Guest and Counterion on the Structural Stability and Electrical Conductivity of Octahedral Metallo-Supramolecular Cages.

Metallo-supramolecular cages have garnered tremendous attention for their diverse yet molecular-level precision structures. However, the physical properties of these supramolecular ensembles, which are of potential significance in molecular electronics, remain largely unexplored. We herein constructed a series of octahedral metallo-cages and cage-fullerene complexes with notably enhanced structural stability.

Metallo-Supramolecular Octahedral Cages with Three Types of Chirality towards Spontaneous Resolution.

Chirality is one of the most important intrinsic properties of (supra)molecules. In this study, we obtained enantiomeric metallo-supramolecular octahedra without using any chiral sources. Such cages were self-assembled by prochiral trispyridine ligand L based on a C truxene core and Cu salts.

A Microporous Metal-Organic Framework with Channels Constructed from Nonpolar Aromatic Rings for the Selective Separation of Ethane/Ethylene Mixtures.

The separation of ethane and ethylene is an important segment in the purification of chemical raw materials in industrial production. However, due to their similar physical and chemical properties, the separation of C H /C H is challenging. Herein, we report the selective adsorption of ethane over ethylene by a microporous metal-organic framework with nonpolar aromatic rings constructed channels, [Co (TATB)(H O) ] ⋅ 5DMA ⋅ 3H O (Co-TATB, H TATB=4,4',4''-(s-triazine-2,4,6-triyl) tribenzoic acid).

Efficient Separation of Acetylene-Containing Mixtures Using ZIF-8 Membranes.

Metal-organic framework (MOF) membranes show great potential in the separation of acetylene mixtures. In this work, we have prepared ZIF-8 membranes on polyamide (PA) substrates for the highly selective separation of acetylene/methane and acetylene/carbon dioxide mixtures. The CH/CH and CH/CO mixtures can be successfully separated using the ZIF-8 membranes, with separation factors of 12.

Two Tb-metal organic frameworks with different metal cluster nodes for CH/CO separation.

Through regulating the reaction solvent and temperature, two Tb-based metal-organic frameworks, ((CH)NH)[Tb(μ-OH)(μ-OH)(PTB)]·(DMF)·(HO) (1) and ((CH)NH){[Tb(μ-O)(μ-OH)(HO)][Tb(μ-O)(HCO) (PTB)]}·(DMF)·(HO) (2) (HPTB = pyridine-2,4,6-tribenzoic acid), have been synthesized. Structural analysis showed that the cluster node of 1 is a Tb cluster, while 2 contains two different nodes of a Tb cluster and a Tb cluster, which leads to their different pore structures and may potentially separate CH/CO. Gas adsorption demonstrates that both MOFs can separate CH and CO, but 2 has a more optimized pore environment than 1 and can exhibit better selective separation of CH/CO.

Integrating the Pillared-Layer Strategy and Pore-Space Partition Method to Construct Multicomponent MOFs for CH/CO Separation.

Introducing multiclusters and multiligands (mm) in a well-defined array will greatly increase the diversity of metal-organic frameworks (MOFs). Here, a series of porous mm-MOFs constructed from a pillared-layer and pore-space partition (PL-PSP) have been achieved. with {Co}-cluster-based sheets and {Co}-cluster-based pillars exhibits new (3,9,12)-connected topology.

Isostructural MOFs with Higher Proton Conductivity for Improved Oxygen Evolution Reaction Performance.

Here we synthesized two new isostructural MOFs (FJU-82-Co/FJU-82-Zn) and first observed that tuning of the proton conductivity may provide an effective strategy to improve the electrocatalytic OER perfomances of isostructural crystalline MOF materials. The conductivity value for FJU-82-Co is 7.40 × 10 S cm, which is 127-fold that for FJU-82-Zn with 5.

MOFs-Derived Nano-CuO Modified Electrode as a Sensor for Determination of Hydrazine Hydrate in Aqueous Medium.

It very important to be able to efficiently detect hydrazine hydrate in an aqueous medium due to its high toxicity. Here, we have proposed a new idea: to construct a sensor for the rapid determination of hydrazine hydrate based on the nano-CuO derived by controlled pyrolysis of HKUST-1 [Cu(BTC)(HO)]. The as-prepared CuO at 400 °C possesses a uniform appearance with nano-structure via SEM images, and the nano-CuO-400 has exhibited excellent electrocatalytic activity towards hydrazine oxidation.

Simultaneous implementation of resistive switching and rectifying effects in a metal-organic framework with switched hydrogen bond pathway.

Resistive random-access memory (RRAM) has evolved as one of the most promising candidates for the next-generation memory, but bistability for information storage, simultaneous implementation of resistive switching and rectification effects, and a better understanding of switching mechanism are still challenging in this field. Herein, we report a RRAM device based on a chiral metal-organic framework (MOF) FJU-23-HO with switched hydrogen bond pathway within its channels, exhibiting an ultralow set voltage (~0.2 V), a high ON/OFF ratio (~10), and a high rectification ratio (~10).

Metal-Organic Framework with Rich Accessible Nitrogen Sites for Highly Efficient CO Capture and Separation.

A novel microporous metal-organic framework (FJU-44), with abundant accessible nitrogen sites on its internal surface, was constructed from the tetrapodal tetrazole ligand tetrakis(4-tetrazolylphenyl)ethylene (HTTPE) and copper chloride. Notably, the CO uptake capacity (83.4 cm/g, at 273 K and 1 bar) in the activated FJU-44a is higher than most of tetrazolate-containing MOF materials.

Enhancement of Intrinsic Proton Conductivity and Aniline Sensitivity by Introducing Dye Molecules into the MOF Channel.

The encapsulation of dyes into metal-organic frameworks (MOFs) has generated a variety of platforms for luminescence, but little attention has been paid to their application in proton conduction. Here, a cationic MOF {{[InOL(HO)](NO)}·(DMA)·(CHCN)·(HO)} (FJU-10, HL = 4,4',4″,4‴-(1,4-phenylenbis(pyridine-4,2,6-triyl))-tetrabenzoic acid, DMA = N, N-dimethylacetamide) was synthesized, and the dye molecule 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt (HPTS) was further added to the MOF growth solution, but during the reaction, HPTS was nitrated and nitrated HPTS was encapsulated into the FJU-10 to obtain dye@FJU-10. As a result, the intrinsic proton conductivity of dye@FJU-10 is nearly 5 times higher than that of FJU-10 at 90 °C.

Pore Space Partition within a Metal-Organic Framework for Highly Efficient CH/CO Separation.

The pore space partition (PSP) approach has been employed to realize a novel porous MOF (FJU-90) with dual functionalities for the challenging CH/CO separation under ambient conditions. By virtue of a triangular ligand (Tripp = 2,4,6-tris(4-pyridyl)pyridine), the cylindrical channels in the original FJU-88 have been partitioned into uniformly interconnected pore cavities, leading to the dramatically reduced pore apertures from 12.0 × 9.

Metalo Hydrogen-Bonded Organic Frameworks (MHOFs) as New Class of Crystalline Materials for Protonic Conduction.

Recently, proton conduction has been a thread of high potential owing to its wide applications in fuel-cell technology. In the search for a new class of crystalline materials for protonic conductors, three metalo hydrogen-bonded organic frameworks (MHOFs) based on [Ni(Imdz) ] and arene disulfonates (MHOF1 and MHOF2) or dicarboxylate (MHOF3) have been reported (Imdz=imidazole). The presence of an ionic backbone with charge-assisted H-bonds, coupled with amphiprotic imidazoles made these MHOFs protonic conductors, exhibiting conduction values of 0.

Two water-stable lanthanide metal-organic frameworks with oxygen-rich channels for fluorescence sensing of Fe(iii) ions in aqueous solution.

The development of metal-organic framework sensors with excellent stability under harsh physical and chemical conditions is of great significance in practical applications. Two isostructural lanthanide-organic frameworks, Ln-MOF ({Ln(L)(H2O)(DMA)}n, {FJU-13-Ln, Ln = Eu, Tb } (H3L = 3,5-(4-carboxybenzyloxy)benzoic acid)), were found to display exceptional stability, not only being stable in both acidic and basic aqueous solutions (pH 3-11), but also maintaining good robustness in boiling water and after activation. Furthermore, the plentiful oxygen atoms in the oxygen-rich channels of FJU-13-Eu and FJU-13-Tb acted as Lewis base sites for sensing metal ions, exhibiting high sensitivity (Stern-Volmer constant, KSV = 2.

Robustness, Selective Gas Separation, and Nitrobenzene Sensing on Two Isomers of Cadmium Metal-Organic Frameworks Containing Various Metal-O-Metal Chains.

Poor stability has been one of the major difficulties affecting to the practical application of metal-organic frameworks (MOFs). In this work, we obtained two 3D structurally isomeric Cd-MOFs, {[Cd(NHMe)(PTB)(HCOO)(HO)]·(DMF)·(HO)} (FJU-35) and {[Cd(NHMe)(PTB)(HCOO)]·(DMF)·(HO)} (FJU-36) (HPTB = pyridine-2,4,6-tribenzoic acid) containing different Cd-O-Cd chains by varying the addition agents. FJU-35 with coordinated solvent and formate in asymmetric μ-η:η coordination mode within the Cd-O-Cd chains is vulnerable to external attacks and is apt to collapse after activation, while FJU-36 with no coordinated solvent in the Cd-O-Cd chains but fully protected by the carboxylates from the ligands and the symmetric formate in the coordination mode μ-η:η is stable, and its activated sample shows efficient separation of CH/CH and CH/CO mixtures.

Mixed-Valence Cobalt(II/III) Metal-Organic Framework for Ammonia Sensing with Naked-Eye Color Switching.

The construction of colorimetric sensing materials with high selectivity, low detection limits, and great stability provides a significant way for facile device implementation of an ammonia (NH) sensor. Herein, with excellent alkaline stability and exposed N sites in molecule as well as with naked-eye color switching nature generated from changeable cobalt (Co) valence, a three-dimensional mixed-valence cobalt(II/III) metal-organic framework (FJU-56) with tris-(4-tetrazolyl-phenyl)amine (HL) ligand was synthesized for colorimetric sensing toward ammonia. The activated FJU-56 demonstrates a limit of detection of 1.