An unusual 8-connected self-penetrating metal–organic framework based on binuclear cadmium clusters

A novel metal–organic framework based on binuclear cadmium clusters has been synthesized and characterized, which represents a new kind of 8-connected uninodal network topology presently known for self-penetrating systems.     

Designed metal–organic framework based on metal–organic polyhedron: Drug delivery

A new metal–organic framework having formula {[NH₂(CH₃)][Cu₆(L)₃(OAc)(H₂O)₄]·xsolvent} (H4L = 3,5-bis(isophthalic acid)-1H-1,2,4-triazole) (1) was synthesized, in which two types of polyhedral cages and one-dimensional channels coexist. The incorporation of the drug 5-fluorouracil (5-FU) into the desolvated 1 was around 24.9 wt% per gram of dehydrated 1. 5-FU is released in a controlled and progressive fashion with 98% of the drug released after 120 h at PBS. The result from this work provides a new avenue for MOF to be used as potential drug delivery.     

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.     

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.     

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 Cd(II) metal–organic framework based on semi-rigid ligand 3,5-(4-carboxybenzyloxy) benzoic acid with high stability by intramolecular hydrogen-bonding

A new metal–organic framework [Cd(HL)]_n (FJU-15, H₃L = 3,5-(4-carboxybenzyloxy) benzoic acid) based on semi-rigid ligand was obtained, which exhibits high stability owing to intramolecular hydrogen-bonding interactions. FJU-15 remains intact in both boiling water and aqueous solutions with pH ranging from 1 to 12, a remarkably extensive pH range that a MOF can sustain. FJU-15 exhibits high thermal stability up to 380 °C, weak second-order nonlinear optical coefficient as 0.31 times as that of potassium dihydrogen phosphate (KDP), and also displays a fluorescence emission band in the ultraviolet region.     

Two 2D metal–organic frameworks based on 2,2′-bibenzimidazole ligand with (6,3) net topology

Two 2D metal–organic frameworks (MOFs), {[Zn₄(Hbbim)₄(bbim)₂] 2H₂O}_n (1) and [Cd₂(Hbbim)₂(bbim)]_n (2) (H₂bbim = 2,2′-bibenzimidazole) were obtained by solvothermal reaction and characterized by single crystal X-ray diffraction analysis. Different metal ions, Cd(II)/Zn(II), adopt very different coordination geometries though two title compounds both have a 2D honeycomb network with (6,3) topology. The frameworks of compounds 1 and 2 are stable below 360 °C and 475 °C, respectively. Solid-state luminescent spectroscopy of compound 2 exhibits an emission peak at 407 nm.     

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.     

A highly rare (3,4,5,6)-connected metal–organic framework containing three distinct Co2 secondary building units

Via solvothermal reaction of CoCl₂ with H₃BTC (1,3,5-benzenetricarboxylic acid) in DMF–C₂H₅OH, a new metal–organic framework (MOF) was isolated. The single crystal X-ray diffraction suggests that the asymmetric unit contains six crystallography-independent Co(II) ions and four deprotonated BTC^3? ligands, and the overall structure of it is a 3D microporous framework with three-dimensional intersecting channel. Further topological analysis reveals a highly rare (3, 4, 5, 6)-connected net.     

3D PbII-coordination framework based on rod-shaped Pb–O–Pb SBUs defining a new (4,5)-connected net topology

A novel 3D coordination framework [Pb₂(hfipbb)₂(bpp)]_n (1) [H₂hfipbb = 4,4′-(hexa-fluoroisopropylidene)bis(benzoic acid), bpp = 1,3-bis(4-pyridyl)propane] based on inorganic rod-shaped infinite Pb–O–Pb chain is presented, which possesses a new (4,5)-connected network topology and shows high thermal stability and strong photoluminescence at room temperature.     

Three-dimensional fivefold interpenetrating microporous metal–organic framework based on mixed flexible ligands

The chiral diamondoidlike Cd(II) containing coordination polymer {[Cd(oba)(bib)]·2H₂O}_n (1) (oba = 4,4′-oxybis(benzoate), bib = 1,4-bis(2-methyl-imidazol-1-yl)butane) is reported; the 3D networks interpenetrate fivefold, nevertheless leave cavities capable of including sizable guest molecules. This compound also exhibits high thermal stability and blue-shift emission, and can be explored for potential blue luminescent materials.     

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.     

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.     

An unprecedented acid/base stable Cu-based metal–organic framework with good catalytic activity for the reduction of 4-nitrophenol

A new 3D metal–organic framework with pcu topology {[Cu₂(TPOM)(ddpa)₂]}_n (1) was synthesized under solvothermal condition by employing flexible tetrakis(4-pyridyloxymethylene) methane (TPOM) and semirigid 4,4′-dicarboxydiphenylamine (H₂ddpa) as well as Cu(II) ion. Complex 1 exhibits good endurance in acid/base aqueous solutions and a high catalytic activity for the reduction of 4-nitrophenol in excess NaBH₄ solution.     

A stable metal–organic framework with well-matched pore cavity for efficient acetylene separation

Acetylene, an important petrochemical feedstock, is the starting chemical to produce many polymer products. Separating C₂H₂ from its by-product mixtures is still an energy-consuming process and remains challenging. Here, we present a metal–organic framework[Zn₂(bpy)(btec)], with a desirable pore geometry and stable framework, which demonstrated a high separation performance of C₂H₂ from simulated mixtures. With the desirable pore dimension and hydrogen bonding sites, Zn₂(bpy)(btec) shows by far the both highest C₂H₂/C₂H₄ and C₂H₂/CO₂ uptake ratios, very high adsorption selectivities and moderately C₂H₂ uptake of 93.5 cm³/cm³ under 298 K and 1 atm. Not only straightforwardly produced high purity of C₂H₄, but also recovered high purity of C₂H₂ (>98%) in the regeneration process (>92% recovery). More notably, Zn₂(bpy)(btec) can be straightforwardly synthesized at a large scale under environmentally friendly conditions, and its good water/chemical stability, thermostability, and cyclic stability highlight the promise of this molecular sieving material for industrial C₂H₂ separation.     

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 new 3D helical silver(I) cluster metal–organic framework with microporous structure and luminescent property

A new 3D helical silver(I) metal–organic polymer of {[Ag₂(ADC)(bib)_0.5]·H₂O}_n (1) (H₂ADC = 1,3-adamantanedicarboxylic acid, bib = 1,4-bis(2-methyl-imidazol-1-yl)butane), has been synthesized and characterized. Compound 1 exhibits significant void space that may be filled with guest H₂O molecules in spite of the metal-cluster that occurs in the solid. Preliminary thermal and fluorescence experiments show that compound 1 possesses strong fluorescent property and thermal stability, respectively.     

One novel near-infrared ytterbium metal–organic framework based on an unprecedented [Yb6(μ2-OH)2(μ3-OH)6]10 + cluster

A novel ytterbium metal–organic framework based on an unprecedented [Yb₆(μ₂-OH)₂(μ₃-OH)₆]^10 + cluster has been obtained and characterized, which shows a rare (3,12)-connected {3².4}₂{3⁸.4²².5²⁴.6¹⁰.7²} topological net and strong near-infrared luminescent emission.     

A microporous [Ni3(μ3-OH)] cluster-based framework with 9-connected ncb topology

A porous metal organic framework [Ni^IIINi^II₂(μ₃-OH)(bdc)_1.5(int)₃]_n x(solvents) (1: bdc = 1,4-benzenedicarboxylate; int = isonicotinate) based on the trinuclear Ni₃(μ₃-OH) units was solvothermally synthesized and structurally characterized. It features a three-dimensional 9-connected ncb-type framework with two kinds of cage substructures and large one-dimensional channels. Both N₂ and CO₂ gas sorption studies of 1 were investigated to demonstrate the permanent porosity in 1.