An amino-functionalized doubly interpenetrated microporous zinc metal–organic framework (UPC-30) has been solvothermally synthesized. UPC-30 can be stable at 190 °C and confirmed by powder X-ray diffraction. Gas adsorption measurements indicate that UPC-30 exhibits high H2 adsorption heat and CO2/CH4 separation efficiency. After the exchange of Me2NH2+ by Li+ in the channels, the H2 adsorption heat increased by 19.7%. Because of the existence of −NH2 groups in the channels, UPC-30 can effectively catalyze Knoevenagel condensation reactions with high yield and pore-size-dependent selectivity.

Metal–organic frameworks (MOFs) derived transition metal oxides exhibit enhanced performance in energy conversion and storage. In this work, porous hollow Co3O4 with N-doped carbon coating (Co3O4/N–C) polyhedrons have been prepared using cobalt-based MOFs as a sacrificial template. Assembled from tiny nanoparticles and N-doped carbon coating, Co3O4/N–C composite shortens the diffusion length of Li+/Na+ ions and possesses an enhanced conductivity. And the porous and hollow structure is also beneficial for tolerating volume changes in the galvanostatic discharge/charge cycles as lithium/sodium battery anode materials. As a result, it can exhibit impressive cycling and rating performance. At 1000 mA g–1, the specific capacities maintaine stable values of ∼620 mAh g–1 within 2000 cycles as anodes in lithium ion battery, while the specific capacity keeps at 229 mAh g–1 within 150 cycles as sodium ion battery anode. Our work shows comparable cycling performance in lithium ion battery but even better high-rate cycling stability as sodium ion battery anode. Herein, we provide a facile method to construct high electrochemical performance oxide/N–C composite electrode using new MOFs as sacrificial template.Keywords: Co3O4/N−C; lithium-ion battery; long-term cycling performance; metal−organic frameworks; sodium-ion battery;

Two-dimensional cobalt oxide (Co3O4) is a promising candidate for robust electrochemical capacitors with high performance. Herein, we use 2,3,5,6-tetramethyl-1,4-diisophthalate as a recyclable ligand to construct a Co-based metal–organic framework of UPC-9, and subsequently, we obtain ultrathin hierarchical Co3O4 hexagonal nanosheets with a thickness of 3.5 nm through a hydrolysis and calcination process. A remarkable and excellent specific capacitance of 1121 F·g–1 at a current density of 1 A·g–1 and 873 F·g–1 at a current density of 25 A·g–1 were achieved for the as-prepared asymmetric supercapacitor, which can be attributed to the ultrathin 2D morphology and the rich macroporous and mesoporous structures of the ultrathin Co3O4 nanosheets. This synthesis strategy is environmentally benign and economically viable due to the fact that the costly organic ligand molecules are recycled, reducing the materials cost as well as the environmental cost for the synthesis process.Keywords: Co(OH)2 nanosheets; Co3O4 nanosheets; eco-friendly; metal−organic framework; self-assembly; supercapacitor;

Two new metal–organic frameworks (MOFs) based on TMBDI linker (TMBDI = 2,3,5,6-tetramethyl-1,4-diisophthalate) and [M2(COO)4] paddlewheel, {[Zn2(TMBDI)(H2O)2]•2.5DMF•2(1,4-dioxane)•6H2O}n (UPC-6) and {[Co2(TMBDI) (DMA)2]•2DMA•5EtOH}n (UPC-8), have been obtained under solvothermal conditions. Due to the low stability of Zn/Co paddlewheels upon the removal of axial solvates, UPC-6 and UPC-8 possesses a very low surface area and adsorption capacity. Through metal-ion metathesis in a single-crystal-to-single-crystal fashion, two new Cu(II) MOFs (termed Cu-UPC-6 and Cu-UPC-8) with identical robust frameworks were produced, which could not be prepared by routine solvothermal methods. Meanwhile, the influence of the reaction solvents on the metathesis process were also investigated, and the results show that the form of solvented ions can induce obviously kinetic issues. Through gas adsorption measurements, the stability and porosity of frameworks have been shown improved significantly.

•The surface wettability switching of MOF mesh is achieved by a facial PDMS modification method.•The JUC-150@PDMS mesh exhibited stable oil-water separation efficiency and flux.•This method is universal and can be extended to other MOF meshes, films and membranes.The surface wettability switching of JUC-150 Metal-Organic Framework (MOF) mesh from hydrophilicity to hydrophobicity was achieved by a facial polydimethylsiloxane (PDMS) modification method. The PDMS modified JUC-150 mesh (JUC-150@PDMS mesh) exhibited high oil-water separation efficiency and flux attributed to the porous structure of the nickel mesh substrate. The passing phase (water or oil) through the MOF mesh can be determined according to the demand, which is of vital importance for industrial applications. Furthermore, this method is universal for other MOF meshes, films and membranes that will be applied in the field of water purification and gas mixture separation with steam.

This work presents the construction of a porous lead-organic framework (UPC-10) with large channels of ∼24 Å. UPC-10 shows efficient adsorption of I2 and selective adsorption of some dyes containing the SO3− group. After the adsorption of dyes, UPC-10 exhibits a CO2 gas uptake ability. Furthermore, UPC-10 could be transformed into PbS in a H2S atmosphere, and the derived PbS manifests N2 and CO2 uptake abilities.

Oil spills have led to more and more energy waste and economic losses all over the world. Developing highly hydrophobic materials for efficient oil/water separation has become key in solving this global issue. Here we report a highly hydrophobic porous metal–organic framework, named UPC-21, constructed from a pentiptycene-based organic ligand, for efficient oil/water separation. Large and pure crystals of UPC-21 could be obtained with high yield through a developed “diauxic growth” strategy. Due to the existence of multi-aromatic hydrocarbon units in the central pentiptycene core of the ligand, UPC-21 exhibits high hydrophobicity with a water contact angle of 145 ± 1° and superoleophilicity with an oil contact angle of 0°. Strikingly, oil/water separation measurements reveal that UPC-21 can efficiently separate toluene/water, hexane/water, gasoline/water, naphtha/water, and crude oil/water with a separation efficiency being above 99.0% except for crude oil/water due to its high viscosity and complex composition. Our work presented here may open a new avenue for the application of porous MOF materials.

The fluorescent Pb(II)–metal–organic nanotube, CD-MONT-2, which possesses a large {Pb14} metallamacrocycle, is synthesized by a modified biphasic liquid–solid–liquid (BLSL) strategy. This strategy takes advantage of solid cyclohexanol to avoid generation of by-products, and is suitable for producing CD-MONT-2 on a large scale. Importantly, water-stable CD-MONT-2 can be easily made into H2S test papers by coating a solution mixture of sodium carboxymethyl cellulose and CD-MONT-2′ on glass plates, which have the characteristics of high efficiency, rapidity, and visualization based on its fluorescence “turn-off” response. The CD-MONT-2 based visual test papers can be used without pretreatment and possess excellent sensitivity and stability.

ZIF-8 is an easily synthesized porous material which is widely applied in gas storage/separation, catalysis, and nanoarchitecture fabrication. Thermally induced atomic displacements and the resultant framework deformation/collapse significantly influence the application of ZIF-8, and therefore, in situ temperature dependent FTIR spectroscopy was utilized to study the framework changes during heating in the oxidative environment. The results suggest that ZIF-8 undergoes three transition stages, which are the lattice expansion stage below 200 °C, the “reversible” structural deformation stage from 200 to 350 °C, and the decomposition/collapse stage over 350 °C. Our research indicates that the Zn–N bond breaks at a temperature of 350 °C in the oxidant environment, leading to a drastic deformation of the ZIF-8 structure.

Herein we provide a new strategy for fluorescence detection of uric acid (UA) using a metal–organic nanotube of CD-MONT-2 for the first time. This novel fluorescent probe exhibits high selectivity and sensitivity for UA with a very good detection limit of 4.3 μM. The results of density functional theory calculations and 1H NMR spectra show that the turn-on sensing mechanism arises from the host–guest interactions of capsule-like CD-MONT-2 with UA to result in electron transfer between UA and CD-MONT-2′. Furthermore, CD-MONT-2′ exhibits very fast adsorption of UA molecules in aqueous solution as confirmed by UV-Vis spectra and HPLC analysis, making it a potential candidate for application in the removal of UA from the human blood.

Herein, we developed an environmentally friendly, feasible method to synthesize pillar[4]arene[1]cis-diepoxy-p-dione. Strikingly, single-crystal X-ray analysis of pillar[4]arene[1]cis-diepoxy-p-dione and 5-chloropentanenitrile indicated a 1:2 stoichiometry to form a 2D network in the solid state.

•Two kinds of conjugated microporous polymers coated superhydrophobic devices were first reported.•The polymer coated stainless steel mesh shows highly oil/water separation efficiency.•Large-scale removing of organic pollution can be realized by polymer-coated sponge.•The trace residual and solved aromatic pollutions can be removed by polymer-coated sponge.Superhydrophobic iron(III) porphyrin-based conjugated microporous polymers (CMPs) are successfully coated on both stainless steel mesh and sponge framework, which are well utilized in separating oil and trace organic contaminants from water for the first time. Due to the superhydrophobic character of the material, the CMP-coated stainless steel and sponge both exhibit high oil/water separation efficiency through filtration and adsorption process, respectively. Furthermore, coated sponges can remove not only the large-scale organic solvents but also the trace organic contaminants from water, which make it an excellent candidate for applications of oil/water separation and water purification.Download high-res image (87KB)Download full-size image

•Four alkaline-earth compounds have been synthesized and structurally characterized.•Four different structures are moderated solely by distinct metal ions.•The weak interactions play important role in construction of compounds.Two new pillar-layered Ba(II)-based 3D frameworks and two new Ca(II)-based 3D supramolecular frameworks, [Ba2(dbtec)(H2O)2]n (1), [Ca2(dbtec)(H2O)8]n (2), {[Ba2(H2btec)·H2O]·0.5H2O}n (3) and [Ca(H2btec)·H2O]n (4) (H4dbtec = 3,6-dibromobenzene-1,2,4,5-tetracarboxylic acid; H4btec = benzene-1,2,4,5-tetracarboxylic acid), have been synthesized under similar reaction conditions and stoichiometry. Single crystal X-ray diffraction study reveals axial-orientation Br···π supramolecular interactions exist in the crystal structure of 1, which keeps an 3D binodal network with the (32.412.510.62.72)(32.46.56.6)2 topology. Whereas in 2, intramolecular and intermolecular H-bonding interactions with the ligated water molecules promote the formation of 3D supramolecular frameworks network. For 3, a new 3D 3-nodal network occurs in the structure and some rare coordination modes for the H4btec are observed. There is a 2D double layer with the thickness of 7.60 Å in 4. In addition, besides the high thermal stability, the FTIR spectra, PXRD patterns and the photoluminescent of these compounds are also discussed.

The assembly of a fluorescent dicarboxylate ligand with a barium ion resulted in the formation of a 3D metal–organic framework, Ba5(ADDA)5(EtOH)2(H2O)3·5DMF (UPC-17), based on a 1D rod-shaped secondary building unit. The unprecedented solvent-dependent sensitivities of UPC-17 for the detection of Fe3+/Al3+ ions and 4-nitrophenol with high efficiency were observed for the first time. Significantly, UPC-17 exhibits superior “turn-off” detection for the Fe3+ ion in methanol and acetone emulsions but shows “turn-on” detection in tetrahydrofuran emulsion. Furthermore, the visible color changes in the detection process make them easy to distinguish by the naked eye, which further increases its application potential.

Metal–organic frameworks (MOFs), composed of organic ligands and metal nodes, are well known for their high and permanent porosity, crystalline nature and versatile potential applications, which promoted them to be one of the most rapidly developing research focuses in chemical and materials science. During the various applications of MOFs, the photoluminescence properties of MOFs have received growing attention, especially for nitroaromatics (NACs) sensing, due to the consideration of homeland security, environmental cleaning and military issues. In this highlight, we summarize the progress in recent research in NACs sensing based on LMOFs cataloged by sensing techniques in the past three years, and then we describe the sensing applications for nano-MOF type materials and MOF film, together with MOF film applications.

Two lanthanide MOFs based on 3,3′-((2,3,6,7-tetramethoxyanthracene-9,10-diyl)bis(4,1-phenylene))diacrylic acid (H2LOMe), [Eu(LOMe)1.5(H2O)2]·3.5DMA·2H2O (1) and [Pr(LOMe)(H2O)4]·2.5DMA·3H2O (2) were synthesized under solvothermal conditions. Complex 1 displayed a 2D net with single nodal 44-sql topology, which further formed a 3D supramolecular architecture by strong π⋯π interaction. Complex 2 featured a 3D open framework with {42·84}-PtS topology. The PL spectrum results showed that 2 has potential application not only in the sensing of small organic molecules, such as DMF and NB, but also in detecting Al3+ and nitroaromatic derivatives. Furthermore, 2 also showed the selective adsorption of CO2 over CH4 and high catalytic activities with the cyanosilylation reaction.

A 3D non-interpenetrating porous metal–organic framework [Pb2(H2TCPP)]·4DMF·H2O (Pb-TCPP) (H6TCPP = 5,10,15,20-tetra(carboxyphenyl)porphyrin) was synthesized by employment of a robust porphyrin ligand. Pb-TCPP exhibits a one-dimensional channel possessing fairly good capability of gas sorption for N2, H2, Ar, and CO2 gases, and also features selectivity for CO2 over CH4 at 298 K. Furthermore, Pb-TCPP shows electrocatalytic activity for water oxidation in alkaline solution. It is the first 3D porous Pb-MOF that exhibits both gas adsorption properties and electrocatalytic activity for an oxygen evolution reaction (OER).

A new 3D porous metal–organic framework [Zn2L2]·5H2O (H2L = 4′-(furan-2-yl)-[2,2′:6′,2′′-terpyridine]-4,4′′-dicarboxylic acid) has been solvothermally synthesized and structurally characterized by TGA, PXRD, elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Complex 1 possesses a 3D porous framework with a sra topology. Gas adsorption measurements with N2, H2 and CO2 confirm its permanent porosity. Importantly, complex 1 exhibits excellent fluorescence properties that have been exploited to sense organic nitro compounds and metal ions, and the results show that complex 1 bears rapid and selective sensing capabilities for 4-NPH and 4-NP through fluorescence quenching.

The current study describes the first barium–organic framework with permanent porosity, efficient catalytic capacity, and highly selective luminescence sensing of DMSO molecules and metal ions. Single-crystal-to-single-crystal transformations (from complex 1 to complexes 2 and 3) were used to thermally generate coordinatively unsaturated metal sites (CUSs) as catalytically active sites (CASs). Complex 3 exhibits efficient catalytic capacity for the cyanosilylation of aldehydes and ketones, and the cycloaddition of CO2 and epoxides. To the best of our knowledge, complex 3 keeps a record among the MOF-based catalysts for the cyanosilylation of aldehydes and ketones. The generation of Ba2+ CUSs with high catalytic activity in a SCSC fashion is responsible for the excellent properties of 3, which is further confirmed by the theoretical calculation. Besides, complex 2 can highly sense DMSO molecules through fluorescence enhancement.

Due to their tunable structure and porosity, metal–organic frameworks have provided a new platform for fluorescence sensing and adsorption/separation of gas or organic molecules. Many studies have focused on sensing metal ions, anions, or organic molecules through fluorescence quenching or enhancement of MOFs, but studies on pH-fluorescence sensors are seldom reported. Furthermore, highly solvent-dependent adsorption and degradation of dye molecules based on functional MOFs has not been explored to date. In this study, we describe a multifunctional Eu MOF, [H3O][Eu3(HBPTC)2(BPTC)(H2O)2]·4DMA (UPC-5, UPC = China University of Petroleum [East China]) based on a tetracarboxylate ligand. The luminescence intensity of UPC-5 is strongly correlated with the pH value in the pH range from 7.5 to 10.0, and a linear relationship between pH value and fluorescent intensity is observed. Another attractive property of UPC-5 is that its Li-exchanged form, Li-UPC-5, possesses solvent-dependent adsorption and degradation of rhodamine B. The highly efficient degradation or decolorization of rhodamine B with long-term stability and activity gives Li-UPC-5 a potential advantage in treating rhodamine B pollution.

Five lanthanide metal–organic frameworks, [Ln(L)(H2O)(NMP)]·1.5H2O (Ln = Ce (1), Pr (2); H3L = 1,3,5-tris(4-carboxyphenyl-1-ylmethyl)-2,4,6-trimethylbenzene), and [Ln2(L)2(H2O)3]·2H2O (Ln = Eu (3), Tm (4), Yb (5)), have been synthesized and characterized. Complexes 1–5 exhibit similar 1D channels through the linkage of Ln-carboxylate chains with the backbones of H3L ligands. The channels for complexes 1 and 2 are occupied by coordinated NMP molecules. 3 shows potential application for the luminescence sensing of small organic molecules. Moreover, 5 exhibits selective adsorption of CO2 over N2 and CH4 and catalytic activities toward the cyanosilylation reaction.

A three-dimensional porous Zn metal–organic framework (UPC-12) with high thermal and chemical stability was isolated in high yield and purity from a hydrothermal reaction. UPC-12 exhibits high selectivity for CO2 due to the formation of hydrogen bonds between CO2 molecules and the −COOH groups exposed inside the channels and the effective π–π interactions between CO2 molecules and the pillared bipyridine moieties of the MOF. The adsorption–desorption process was studied, for the first time, by both 13C CP-TOSS NMR spectroscopy and in situ DRIFTS.

A pair of framework-catenation isomers (UPC-19 and UPC-20) based on an anthracene-functionality dicarboxylate ligand were synthesized and characterized for the first time through tuning of the dimensionality of interpenetration. The interpenetration dimensionality significantly influences the properties including the porosity, gas-uptake capacity, and fluorescent sensing ability: UPC-19 with 5-fold interpenetration is nonporous, whereas the 3-fold interpenetration form of UPC-20 is porous and exhibits selective adsorption of CO2 and fluorescent sensing of Cu2+ and Fe3+ through fluorescence quenching.

Four metal–organic complexes [Ni(HET)(phen)(H2O)]·(HET)·H2O (1), [Cu(HET)(phen)(H2O)]·1.5H2O (2), [Cu2(HET)2(bipy)1.5(H2O)]·15DMF·2H2O (3), and [Cd2O(HET)2(bipy)(H2O)]·2H2O·EtOH (4) (HET = 1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid, phen = 1,10-phenanthroline, bipy = 4,4′-bipyridine) have been synthesized via hydro- or solvothermal reactions. It was found that complexes 1 and 2 are two-dimensional (2D) structures built from discrete complexes via the typical intermolecular interactions, and there was a closed loop built from the lattice water and carboxylate groups in 1 through intramolecular hydrogen bonds. Complex 3 exhibits three-dimensional (3D) structure with 5-connected bnn hexagonal BN topology. Complex 4 features a non-interpenetrating sql 2D coordination network, which is further linked into a 3D structure by C–H···Cl weak interaction. The properties of magnetism, fluorescence, and electrochemistry have also been investigated in this paper.

An open terbium-organic framework (UPC-11) based on a rigid tetracarboxylate ligand was successfully assembled, which exhibits excellent solvent-dependent photoluminescence (PL). Moreover, UPC-11 displays rapid and selective sensing of nitroaromatic compounds (NACs), especially for 4-nitrophenol (4-NP), which represents the first Tb MOF that can be used as fluorescence detection of 4-NP.

Three new metal–organic frameworks (MOFs) constructed from terphenyl-3,3′′,5,5′′-tetracarboxylic acid (H4ptptc) and zinc nitrate, [Zn2(ptptc)(DMF)3]·4H2O·5.5DMF (1), [Zn2(ptptc)(DMA)(H2O)]·2.5H2O·3.5DMA (2) and [Zn(ptptc)0.5(H2O)]·DMF·DMA (3), have been obtained and characterized. All the complexes exhibit 3D 4-connected networks with different topologies involving diamond (dia, for 1), lonsdaleite (lon, for 2) and Nbo (for 3), which emanate from the different reaction solvents (DMF, DMA and mixture of DMF/DMA (1:1), respectively). The results of photoluminescence properties show that the three complexes can be act as potential luminescent probes or sensors for detecting small organic molecules and toxic substances.

Two porous metal–organic frameworks (1 and 2) with a fsc topology based on mixed ligands have been assembled and characterized. The different pillared ligands (pyrazine for 1 and 4,4′-bipyridine for 2) significantly influence the pore size of the frameworks. Gas uptake measurements reveal that complex 1 possesses higher H2, CO2, and CH4 uptake capacities than 2, although the surface area of 1 is lower than that of complex 2. These results further experimentally prove that the pore size plays an important role in gas uptake in porous MOFs, and the slit pore with a size of ∼6 Å exhibits stronger interactions with gas molecules.

Two rht anionic metal–organic frameworks were synthesized. There are six [M(H2O)6]2+ ions held together by a super-strong H-bond and arranged in a regular octahedron in each medium cage. Dye adsorption studies revealed a rapid and selective adsorption of cationic dyes and the adsorbed dyes can be released in saturated NaCl aqueous solution.

A new porous zirconium metal–organic framework (Zr MOF), Zr6(μ3-O)4(μ3-OH)4(OH)6(H2O)6(BTB)2·6DMF·H2O (1; H3BTB = 5′-(4-carboxyphenyl)[1,1′:3′,1″-terphenyl]-4,4″-dicarboxylic acid), based on Zr6 clusters and tricarboxylate ligands has been constructed and characterized. The Zr6 clusters were linked by BTB ligands to generate a 2D network of kgd topology. The interpenetrations among the 2D networks gave rise to a 3D porous framework, which represents the first Zr MOF constructed from 2D → 3D interpenetration. The gas uptake and catalytic properties for 1 have also been studied.

Seven novel silver(I) coordination networks with mixed flexible 3,3′,5,5′-tetramethyl-4,4′-bipyrazole (bpz) and C3–C9 aliphatic dicarboxylic acids, [Ag2(bpz)4(mal)·7H2O]n (1L and 1R), [Ag2(bpz)3(suc)]n (2), [Ag4(bpz)5(glu)2]n (3), [Ag4(bpz)5(adip)2]n (4), [Ag4(bpz)7(pim)2·12H2O]n (5), [Ag2(bpz)4(sub)·7H2O]n (6), and [Ag2(bpz)3(aze)·3.5H2O]n (7) (H2mal = malonic acid, H2suc = succinic acid, H2glu = glutaric acid, H2adip = adipic acid, H2pim = pimelic acid, H2sub = suberic acid, H2aze = azelaic acid), have been synthesized and structurally characterized by single-crystal X-ray diffraction analyses and further characterized by infrared spectra (IR), elemental analyses, powder X-ray diffraction (PXRD), and thermogravimetric analyses (TGA). Single crystal X-ray diffraction analysis reveals that 1 crystallized into a pair of enantiomerically pure 3D 3-fold interpenetrated chiral SrSi2 networks (point symbol {103}) through spontaneous resolution in the absence of any chiral source. Complex 2 is a 3D 2-fold interpenetrated 3-connected uninodal dia-f network (point symbol {4·142}) without consideration of Ag···Ag interaction. Complexes 3 and 4 are similar 2D + 2D → 2D 63-hcb layer featuring 3-fold parallel interpenetration. Complex 5 is a 3D 3-fold interpenetrated 3,4-connected 3,4T1 network (point symbol {4·6·8}{4·62·83}). Complexes 6 and 7 are similar 2D + 2D → 2D fes layers (point symbol {4·82}) featuring 3-fold parallel interpenetration. In 1–7, structural diversity ranging from 2D hcb and fes layers to 3D chiral SrSi2, achiral dia-f, and 3,4T1 networks is modulated by dicarboxylates with alkyl chains of different lengths. Interestingly, a well-resolved octanuclear water cluster built from a chairlike (H2O)6 cluster and two water molecules dangling on two corners of it and a unusual seesaw-like pentanuclear water cluster is observed in the voids of 5 and 7, respectively. Furthermore, the solid-state photoluminescence properties of the 1–7 were investigated at 298 and 77 K.

A luminescent europium–organic framework with tubular channels based on the H4BTMIPA ligand (H4BTMIPA = 5,5′-methylenebis(2,4,6-trimethylisophthalic acid)) was assembled and characterized. The [H2N(CH3)2]+ ions as counterions are located in the channels. The cation exchange between [H2N(CH3)2]+ and metal ions resulted in complex 1 that can selectively sense Fe3+ and Al3+ ions through fluorescence quenching and enhancement, respectively.

Two isomorphous lanthanide–organic frameworks, Ln(BDC)1.5(DMF)(H2O) (Ln = Er (1), Tm (2)) have been synthesized based on 1,4-benzenedicarboxylic acid (H2BDC). Because of the 2-fold interpenetration, the pores are partly blocked and there are no significant gas adsorptions for these two interpenetrating nets. Through control over interpenetration by applying an organic ligand with hindrance groups or replacing coordinated solvent molecules with a chelating ligand, three non-interpenetrating lanthanide–organic frameworks, Er2(BDC)3(phen)2·3H2O (3), Tm(TBDC)1.5(DMF)(H2O)·2H2O (4), Er2(TBDC)3(phen)2·4DMF·2H2O (5), possessing the same topology with 1 and 2, have been synthesized and characterized. Further changing reaction conditions, three other porous lanthanide–organic frameworks with different structures with 1–5, Tm(BDC)1.5(H2O)·0.5DMF·C2H5OH·2H2O (6), Tm4(BDC)6(H2O)2(DMF)(C2H5OH)·2DMF·2H2O (7), and Sm(TBDC)1.5(phen)(H2O)·DMF·H2O (8), have been constructed. Gas sorption measurements for 5, 6, 7, and 8 have been carried out and revealed that these materials possess permanent porosity. The catalytic property for complex 6 has also been studied.

Two 2D silver lamella frameworks, [Ag4(C5H4NS)2(NO3)2]n (1) and [Ag3(C5H4NS)2]n·nClO4 (2) based on binuclear units have been solvothermally synthesized. The C5H4NS ligand was in situ generated from the cleavage of bis(2,4,6-trimethyl-3,5-bis((pyridin-2-ylthio)methyl)phenyl)methane (bmpm). Furthermore, the formation of 1 and 2 was also controlled by anions involved in the reaction. Short Ag–Ag interactions were also found in 1 and 2.

Solvothermal reactions of 5-hydroxyisophthalic acid (hip) and different N-containing auxiliary ligands with transition metal salts provided four new metal–organic coordination polymers (MOPs), namely, {Zn(hip)(2,2′-bipy)·2H2O}n (1), {[Ni(hip)(4,4′-bipy)(H2O)]·DMF·2H2O}n (2), {Zn(hip)(tib)·2H2O}n (3), {[Zn2(hip)2]·5H2O}n (4), (2,2′-bipy = 2,2′-bipyridine, 4,4′-bipy = 4,4′-bipyridine, DMF = N,N′-dimethylformamide, tib = 1,3,5-tris(1-imidazolyl)benzene). All of the complexes have been structurally characterized by single-crystal X-ray diffraction analyses, infrared spectra (IR), elemental analyses and powder X-ray diffraction (PXRD). Single crystal X-ray diffraction analysis reveals that complex 1 exhibits a one-dimensional zig-zag chain, in which strong π⋯π interactions are found between neighbouring 2,2′-bipy molecules. Complex 2 has a 2D double-layer square framework, exhibiting AA stacking sequence, and the topology of each layer is typical 2D (44)-sql. In complex 3, both hip and tripodal ligand tib act as bidentate bridging ligand and extend the tetragonal pyramid Zn(II) centers to a 2D wavy framework, exhibiting an AB stacking sequence. The 2D layer structures in 2 and 3 are different from each other. In complex 4, the oxygen atoms of the hydroxy group of hip participate in constructing a framework, which results to the 3D net framework with 1D channel. The structural and topological differences of the four MOPs indicate that the auxiliary ligand play important roles in the formation of final structures. Furthermore, the thermal stability and photoluminescence properties of complexes 1–4 were investigated.

Two porous metal–organic frameworks (1 and 2) with a fsc topology based on mixed ligands have been assembled and characterized. The different pillared ligands (pyrazine for 1 and 4,4′-bipyridine for 2) significantly influence the pore size of the frameworks. Gas uptake measurements reveal that complex 1 possesses higher H2, CO2, and CH4 uptake capacities than 2, although the surface area of 1 is lower than that of complex 2. These results further experimentally prove that the pore size plays an important role in gas uptake in porous MOFs, and the slit pore with a size of ∼6 Å exhibits stronger interactions with gas molecules.

Two lanthanide MOFs based on 3,3′-((2,3,6,7-tetramethoxyanthracene-9,10-diyl)bis(4,1-phenylene))diacrylic acid (H2LOMe), [Eu(LOMe)1.5(H2O)2]·3.5DMA·2H2O (1) and [Pr(LOMe)(H2O)4]·2.5DMA·3H2O (2) were synthesized under solvothermal conditions. Complex 1 displayed a 2D net with single nodal 44-sql topology, which further formed a 3D supramolecular architecture by strong π⋯π interaction. Complex 2 featured a 3D open framework with {42·84}-PtS topology. The PL spectrum results showed that 2 has potential application not only in the sensing of small organic molecules, such as DMF and NB, but also in detecting Al3+ and nitroaromatic derivatives. Furthermore, 2 also showed the selective adsorption of CO2 over CH4 and high catalytic activities with the cyanosilylation reaction.

A 3D non-interpenetrating porous metal–organic framework [Pb2(H2TCPP)]·4DMF·H2O (Pb-TCPP) (H6TCPP = 5,10,15,20-tetra(carboxyphenyl)porphyrin) was synthesized by employment of a robust porphyrin ligand. Pb-TCPP exhibits a one-dimensional channel possessing fairly good capability of gas sorption for N2, H2, Ar, and CO2 gases, and also features selectivity for CO2 over CH4 at 298 K. Furthermore, Pb-TCPP shows electrocatalytic activity for water oxidation in alkaline solution. It is the first 3D porous Pb-MOF that exhibits both gas adsorption properties and electrocatalytic activity for an oxygen evolution reaction (OER).

A luminescent europium–organic framework with tubular channels based on the H4BTMIPA ligand (H4BTMIPA = 5,5′-methylenebis(2,4,6-trimethylisophthalic acid)) was assembled and characterized. The [H2N(CH3)2]+ ions as counterions are located in the channels. The cation exchange between [H2N(CH3)2]+ and metal ions resulted in complex 1 that can selectively sense Fe3+ and Al3+ ions through fluorescence quenching and enhancement, respectively.

Two rht anionic metal–organic frameworks were synthesized. There are six [M(H2O)6]2+ ions held together by a super-strong H-bond and arranged in a regular octahedron in each medium cage. Dye adsorption studies revealed a rapid and selective adsorption of cationic dyes and the adsorbed dyes can be released in saturated NaCl aqueous solution.

This work presents the construction of a porous lead-organic framework (UPC-10) with large channels of ∼24 Å. UPC-10 shows efficient adsorption of I2 and selective adsorption of some dyes containing the SO3− group. After the adsorption of dyes, UPC-10 exhibits a CO2 gas uptake ability. Furthermore, UPC-10 could be transformed into PbS in a H2S atmosphere, and the derived PbS manifests N2 and CO2 uptake abilities.

The current study describes the first barium–organic framework with permanent porosity, efficient catalytic capacity, and highly selective luminescence sensing of DMSO molecules and metal ions. Single-crystal-to-single-crystal transformations (from complex 1 to complexes 2 and 3) were used to thermally generate coordinatively unsaturated metal sites (CUSs) as catalytically active sites (CASs). Complex 3 exhibits efficient catalytic capacity for the cyanosilylation of aldehydes and ketones, and the cycloaddition of CO2 and epoxides. To the best of our knowledge, complex 3 keeps a record among the MOF-based catalysts for the cyanosilylation of aldehydes and ketones. The generation of Ba2+ CUSs with high catalytic activity in a SCSC fashion is responsible for the excellent properties of 3, which is further confirmed by the theoretical calculation. Besides, complex 2 can highly sense DMSO molecules through fluorescence enhancement.

Five lanthanide metal–organic frameworks, [Ln(L)(H2O)(NMP)]·1.5H2O (Ln = Ce (1), Pr (2); H3L = 1,3,5-tris(4-carboxyphenyl-1-ylmethyl)-2,4,6-trimethylbenzene), and [Ln2(L)2(H2O)3]·2H2O (Ln = Eu (3), Tm (4), Yb (5)), have been synthesized and characterized. Complexes 1–5 exhibit similar 1D channels through the linkage of Ln-carboxylate chains with the backbones of H3L ligands. The channels for complexes 1 and 2 are occupied by coordinated NMP molecules. 3 shows potential application for the luminescence sensing of small organic molecules. Moreover, 5 exhibits selective adsorption of CO2 over N2 and CH4 and catalytic activities toward the cyanosilylation reaction.

Due to their tunable structure and porosity, metal–organic frameworks have provided a new platform for fluorescence sensing and adsorption/separation of gas or organic molecules. Many studies have focused on sensing metal ions, anions, or organic molecules through fluorescence quenching or enhancement of MOFs, but studies on pH-fluorescence sensors are seldom reported. Furthermore, highly solvent-dependent adsorption and degradation of dye molecules based on functional MOFs has not been explored to date. In this study, we describe a multifunctional Eu MOF, [H3O][Eu3(HBPTC)2(BPTC)(H2O)2]·4DMA (UPC-5, UPC = China University of Petroleum [East China]) based on a tetracarboxylate ligand. The luminescence intensity of UPC-5 is strongly correlated with the pH value in the pH range from 7.5 to 10.0, and a linear relationship between pH value and fluorescent intensity is observed. Another attractive property of UPC-5 is that its Li-exchanged form, Li-UPC-5, possesses solvent-dependent adsorption and degradation of rhodamine B. The highly efficient degradation or decolorization of rhodamine B with long-term stability and activity gives Li-UPC-5 a potential advantage in treating rhodamine B pollution.

Herein we provide a new strategy for fluorescence detection of uric acid (UA) using a metal–organic nanotube of CD-MONT-2 for the first time. This novel fluorescent probe exhibits high selectivity and sensitivity for UA with a very good detection limit of 4.3 μM. The results of density functional theory calculations and 1H NMR spectra show that the turn-on sensing mechanism arises from the host–guest interactions of capsule-like CD-MONT-2 with UA to result in electron transfer between UA and CD-MONT-2′. Furthermore, CD-MONT-2′ exhibits very fast adsorption of UA molecules in aqueous solution as confirmed by UV-Vis spectra and HPLC analysis, making it a potential candidate for application in the removal of UA from the human blood.

Oil spills have led to more and more energy waste and economic losses all over the world. Developing highly hydrophobic materials for efficient oil/water separation has become key in solving this global issue. Here we report a highly hydrophobic porous metal–organic framework, named UPC-21, constructed from a pentiptycene-based organic ligand, for efficient oil/water separation. Large and pure crystals of UPC-21 could be obtained with high yield through a developed “diauxic growth” strategy. Due to the existence of multi-aromatic hydrocarbon units in the central pentiptycene core of the ligand, UPC-21 exhibits high hydrophobicity with a water contact angle of 145 ± 1° and superoleophilicity with an oil contact angle of 0°. Strikingly, oil/water separation measurements reveal that UPC-21 can efficiently separate toluene/water, hexane/water, gasoline/water, naphtha/water, and crude oil/water with a separation efficiency being above 99.0% except for crude oil/water due to its high viscosity and complex composition. Our work presented here may open a new avenue for the application of porous MOF materials.