A new 3D metal–organic framework based on a hexanuclear cobalt(II): Synthesis,structure, and magnetic property

A new 3D framework 1 based on {Co₆} cluster as node was successfully synthesized and fully characterized, which showed an 8-connected bcu topology with the Schläfli symbol of {4²⁴,6⁴}. Furthermore, the thermal stability and magnetic property reveal that 1 displays high thermal stability and antiferromagnetic interaction among the Co^II spin carries.     

A metal–organic framework containing meso-helical chains: Synthesis,characterization and luminescent property

A new metal–organic frameworks (MOFs), [Cd₃(pmb)₂(bpdc)₂] 2H₂O (1) (pmb = 3,5-bis(4-pyridylmethylenoxyl)benzoate, bpdc = 2,2′-biphenyldicarboxylate), has been synthesized by hydrothermal method and structurally characterized through IR, TG and single-crystal X-ray analysis. The infinite wave-like 1D metal–oxygen chains made by Cd₃N₄O₁₂ clusters in 1 bridged by the carboxylate of bpdc ligand, construct a 2D framework in which interesting meso-helical chains are constructed by metal centers and pmb ligands. Solid state luminescent spectrum of 1 also has been investigated at room temperature.     

A porous lanthanide metal–organic framework with luminescent property,nitrogen gas adsorption and high thermal stability

A novel lanthanide metal–organic framework, [Eu₂(BDC)₃(DMF)₂]·(DMF)_1.7(BDC = 1,3-benzenediacarboxylate) 1 has been synthesized under solvothermal condition and characterized by single-crystal X-ray structure determination, luminescent property, nitrogen gas adsorption, powder X-ray diffraction, IR, and TGA.     

A new self-penetrating amine-decorated microporous metal–organic framework: Crystal structure,adsorption selectivity,and luminescence properties

A new microporous metal–organic framework, [Cd(bpdc)_0.5(atz)(DMF)]·0.5DMF (1) (H₂bpdc = 4,4′-biphenyldicarboxylic acid, Hatz = 3-amino-1,2,4-triazole, DMF = N,N-dimethylformamide) has been solvothermally synthesized by employing the mixed H₂bpdc and Hatz ligands. 1 is a 3D pillared-layer framework, consisting of Cd–triazolate layer and dicarboxylate pillar, which exhibits a 6-connected (4⁶ · 6⁸ · 8) self-penetrating net. Because of the pore system functionalized by amino groups and open metal sites, this material shows high CO₂ adsorption selectivity over H₂ and N₂. In addition, 1 exhibits blue emission at ambient temperature.     

A luminescent [Ag3S3]n-tube based metal–organic framework

Solvothermal treatment of silver nitrate, pyridine-4-thione (4-pdtH) and NH₄SCN at 140 °C for 3 days produced a three-dimensional metal–organic framework [Ag₃(4-pdt)(SCN)₂] (1) in which [Ag₃S₃]_n tubes act as secondary building units and pyridine rings and CN groups act as linkers. At ambient temperature, 1 shows a blue emission band assigned as from a ligand-centred n → π¹ or π → π¹ process.     

Microporous metal–organic framework with 1D helical chain building units: Synthesis,structure and gas sorption properties

The design, synthesis, and structural characterization of a new anionic metal-organic framework, namely, {(H₂N(Me)₂)[Cu(bidc)](H₂O)₃}_n (1), with 1D helical metal chains is reported here. The title complex was synthesized by solvothermal reaction of Cu(NO₃)₂·3H₂O and benzimidazole-5,6-dicarboxylic acid (H₃bidc) in a mixed solvent of DMF, 1,4-dioxane, H₂O and HNO₃ (aq) at 120 °C for three days, which reveals a 3D porous framework with 1D nanotubular channels running along the c axis. The pore characteristics and gas sorption properties of this compound were investigated at both cryogenic temperature and room temperature by experimentally measuring N₂, CH₄ and CO₂ adsorption/desorption isotherms. The amount of the N₂ and CO₂ uptake is 146 cm³/g at 77 K and 52 cm³/g at 273 K, which is the highest among MOFs constructed from the H₃bidc ligand. In addition the activated 1 shows high adsorption selectivity of CO₂ over CH₄ at room temperature.     

A luminescent novel octanuclear silver(I) cluster framework with potential Cr2O72 − sensing

An unique and novel octanuclear silver(I) cluster compound, [Ag₈(ADC)₄]_n (1) (H₂ADC = 1,3-adamantanedicarboxylic acid), has been synthesized and characterized. Compound 1 exhibits significant Ag–Ag interactions to form 2D infinite silver layers with multiple unsaturated Ag atoms. Moreover, Luminescent investigations show that 1 can exhibit highly selective response to Cr₂O₇^2 − through luminescence quenching effect in aqueous solution, which make its good candidate as luminescent sensor.     

Separation of propylene and propane with a microporous metal–organic framework via equilibrium-kinetic synergetic effect

Adsorption separation of olefin and paraffin can greatly lower the energy consumption associated with the currently utilized distillation technique but remains a great challenge. Herein, we report the efficient separation of propylene (C₃H₆) and propane (C₃H₈) in a phosphate anion-functionalized metal–organic framework (MOF) ZnAtzPO₄ by synergetic effect of equilibrium and kinetics. The material features periodically expanded and contracted apertures decorated with electronegative groups, offering eligible pore shape and pore chemistry to effectively trap C₃H₆ under moderate isosteric heat of adsorption (27.5 kJ mol⁻¹) while obstruct the diffusion of C₃H₈. It simultaneously combines excellent thermodynamic selectivity (uptake ratio of 1.71) and kinetic selectivity (~31) for C₃H₆/C₃H₈ separation, meanwhile can be easily regenerated. Breakthrough experiment for C₃H₆/C₃H₈ gas mixture was conducted and confirmed the outstanding separation capability of ZnAtzPO₄. The equilibrium and kinetics cooperative C₃H₆/C₃H₈ adsorption separation was for the first time found in anion-functionalized MOFs, and further confirmed by computational studies.     

Three-dimensional microporous metal–organic framework constructed from Cadmium(II) ion with terephthalate and in-situ generated amino-tetrazole mixed-ligands

A new coordination polymer, [Cd₄(atz)₆(PTA)]_n has been firstly synthesized by employing mixed-ligand of terephthalic acid (PTA) with the in-situ generated ligand of 5-amino-tetrazolate (atz^?). Compound 1 represents a 3D microporous framework constructed from Cd-tetrazolate subunits and the subunits are bridged by PTA and atz ligands. When the subunit was collided into node, compound 1 possesses an unprecedented 3, 9-connected topological network. Furthermore, the investigations of thermal stability and luminescent property of complex 1 indicate that compound 1 may be an excellent candidate for potential blue-light emitting material.     

An unprecedented ten-connected 3D metal–organic framework based on hexanuclear cobalt(II) cluster building blocks

A 3D metal–organic framework (MOF), [Co₃(μ₃-OH)(μ₂-H₂O)(BPT)(HBPT)(DMF)₂]·(DMF)(H₂O) (1) (DMF = N, N′-dimethylformamide) has been synthesized by self-assembly of cobalt(II) oxide and biphenyl-3, 4′, 5-tricarboxylate (H₃BPT) under solvothermal reaction. Compound 1 displays unique (2,3,10)-connected trinodal connected topology. Besides, 1 represents a rare example of MOF possessing free carboxylic acids. In addition, the magnetic property of the compound is investigated.     

A new (3,8)-connected pillared-layer lanthanide–organic framework with interconnected channel and mesoporous cage

A novel non-interpenetrated lanthanide–organic framework constructed by dinuclear cerium cluster as pillar and trinuclear cerium cluster as layer with a uniform (3,8)-connected topology has been reported, which exhibits mesoporous cages between layers and 3D interconnected channels.     

Synthesis,crystal structure,luminescent property and DFT investigation on a novel metal–organic framework constructed from rigid tetrapodal ligand 1,2,3,4-tetra(4-pyridyl)thiophene

Employing the tetrapodal compound 1,2,3,4-tetra(4-pyridyl)thiophene (TPT) as a bridging ligand, a new metal–organic framework was obtained and characterized by single crystal X-ray diffraction, [Cd(TPT)(N₃)₂·(H₂O)] (1). This polymer exhibits a 2D layer network and an unprecedented 3,4-connected topology, which is constructed from the three-connector TPT and EE azido bridges. It also displays good thermal stability and strong photoluminescence in the blue regionband thus may serve as a candidate of thermally stable blue-light-emitting electroluminescence material. The nature of electronic transitions in the photoluminescent process has also been investigated by means of time-dependent density functional theory (TDDFT) calculations and molecular orbital analyses, which shows that the luminescent property is ligand-based.     

Study on a new cyclodextrin based metal–organic framework with chiral helices

Staring from β-cyclodextrins and Na salts, a new metal–organic framework with chiral helices, (C₄₂O₃₅H₇₀)₂(NaOH)₄·H₂O (CD-MOF-1), has been successfully synthesized. X-ray diffraction analysis reveals that CD-MOF-1 exhibits a 3D framework with left-handed helical channels running through the structure created by the ligation of Na ions to the primary and secondary faces of the β-cyclodextrins rings. Additionally, inclusion properties of CD-MOF-1 were also studied, and the result shows that the inclusion rate using CD-MOF-1 as inclusion materials is higher than that of β-cyclodextrins, which is expected to become a new type of green crystal material from edible natural products.     

A novel 3D zinc metal–organic framework based on the tetrazole-containing ligand and tricarboxylic acid

A novel zinc metal–organic framework (MOF) with the combination of 5,5′-(1,4-phenylene)bis(1H-tetrazole) (H₂BDT) and 1,3,5-benzenetricarboxylic acid (H₃BTC) as the mixed ligands, namely [Me₂NH₂]₄Zn₂(BDT)(BTC)₂ 2DMF (1), has been solvothermally synthesized and characterized. Single-crystal X-ray analysis reveals that the structure of 1 features a pillared-layered three-dimensional (3D) anionic framework of [Zn₂(BTC)₂(BDT)]_n⁴ⁿ⁻. The luminescent property studies indicated that 1 might be a potential blue-light material. It was found that the introduction of H₃BTC could exhibit an obvious influence on the luminescence of 1, which can help us in better designing luminescent MOF materials.     

Construction of silver–organic framework with silver rods of repeated Ag-triangle units: Synthesis,structure, and properties

A new thick silver rod incorporating repeated Ag₃ units sustained by 1,3,5-benzenetricarboxylic acid (1,3,5-H₃BTC) and Ag⋯Ag interactions, {[Ag₃(BTC)(pyz)]·(H₂O)}_n (1) (pyz = pyrazine), has been synthesized and structurally characterized. Compound 1 displays a three-dimensional coordination framework with infinite 1D Ag rod, and adjacent silver rods bridged by the 1,3,5-H₃BTC and pyz ligand. Argentophilicity plays an important role in determining the infinite silver(I) rods. Complex 1 exhibits photoluminescence maximized at 542 nm upon 363 nm excitation at room temperature, which may be mainly assigned to ligand-to-metal charge transfer (LMCT) perturbed by Ag⋯Ag interactions. Temperature dependent luminescence spectra from 298 to 77 K have been studied. Upon decreasing the temperature from 298 to 77 K, the emission bands grow in intensity. In addition, the thermogravimetric analysis and powder X-ray diffraction (PXRD) of complex 1 have also been investigated.     

A new 3D Keggin-POM based metal–organic framework of Cu and H2biim: Assembly and properties of fluorescence and electrochemistry

A new 3D Keggin-based metal–organic framework consisting of two kinds of Cu-H₂biim chains, Cu₁₀(H₂biim)₁₀(PW₁₂O₄₀)₂(OH)₄·5H₂O 1 (H₂biim = 2,2′-biimidazole), has been synthesized under hydrothermal conditions. The TGA and PXRD measurements show that the framework is stable after removal of the guest water molecules. In addition, the luminescent and electrochemical properties of 1 have also been investigated.     

A new 3D Cd(II) metal–organic framework with discrete (H2O)6 clusters based on flexible cyclohexane-1,2,4,5-tetracarboxylic acid ligand

A 3D metal–organic framework (MOF), {[Cd₂(CTA)(bpp)₂(H₂O)₂] (H₂O)₃}_n (1) (H₄CTA = cyclohexane-1,2,4,5-tetracarboxylic acid, bpp = 1,3-bis(4-pyridyl)propane), has been synthesized and structurally characterized by elemental analysis, IR and powder X-ray diffraction. Single-crystal X-ray measurement reveals that the complex presents three-dimensional frameworks with 1D channels which are filled by unique (H₂O)₆ clusters. Noteworthily, the H₄CTA ligands keep exclusive conformation, where the carboxyl groups adopt different coordination modes, and the bpp ligands perform two different conformations. Thermogravimetric analysis demonstrates that 1 features favorable thermal stability. Photoluminescence property of 1 is investigated in the solid state at room temperature as well.     

Dense open metal sites in a microporous metal–organic framework for deep desulfurization with record-high sulfur dioxide storage density

Dry desulfurization employing porous adsorbents is industrially preferred but efficient capture of sulfur dioxide (SO₂) at the ultralow concentration (i.e., 2000 ppm) is exceptionally challenging. Metal–organic frameworks with open metal sites (OMSs) can provide sufficient interactions with SO₂, which, in turn, will degrade or compromise the structural robustness. Herein, we reported Cu-ATC that contains dense oppositely positioned Cu OMSs for efficient trace SO₂ removal. Explicitly, Cu-ATC adsorbs a benchmark amount of SO₂ (5.3 mmol g⁻¹) at 0.01 bar with a record-high SO₂ storage density of 2.23 g cm⁻³ at ambient conditions. The critical role of OMSs has been confirmed by the partially desolvated sample with declined uptakes and adsorption enthalpy. The desulfurization performances have been validated by multicycle breakthrough experiments even with mimic flue-gas and water vapor. Computational simulations identify the adsorption sites at the molecular level. Combined with the high stability under various conditions, Cu-ATC is a potent candidate for industrial implementation.     

Synthesis,structure and gas adsorption properties of a microporous metal–organic framework assembled from a semi-rigid tripodal carboxylic acid ligand

The design, synthesis, and structural characterization of a new cubic three-dimensional microporous metal–organic framework featuring a semi-rigid tripodal carboxylic acid ligand, 4,4′-((5-carboxy-1,3-phenylene)bis(oxy))dibenzoic acid (H₃cpbda), is reported. Single-crystal X-ray diffraction analysis indicates that compound 1 possesses a novel (3,4,4)-connected network with the point symbol of {8³}₄{8⁴·10²}₂{8⁶}. In the framework of 1, there co-exist two types of 1D channels with different pore size (15 Å and 4.5 Å). The pore characteristics and gas sorption properties of this compound were investigated both at cryogenic temperatures and room temperature by experimentally measuring N₂ and CO₂ sorption isotherms. These studies show that compound 1 is highly porous with a pore volume of 0.98 cm³/g and BET surface of 1926 cm³/g. In addition, the activated 1 also shows excellent CO₂ storage capacity around room temperature.