Zinc Metal-organic Framework Research Articles

Quasi-Orthogonal Configuration of Propylene within a Scalable Metal-Organic Framework Enables Its Purification from Quinary Propane Dehydrogenation Byproducts.

Propylene production via nonoxidative propane dehydrogenation (PDH) holds great promise in meeting growing global demand for propylene. Effective adsorptive purification of a low concentration of propylene from quinary PDH byproducts comprising methane (CH4), ethylene (C2H4), ethane (C2H6), propylene (C3H6), and propane (C3H8) has been an unsolved academic bottleneck. Herein, we now report an ultramicroporous zinc metal–organic framework (Zn-MOF, termed as 1) underlying a rigid one-dimensional channel, enabling trace C3H6 capture and effective separation from quinary PDH byproducts. Adsorption isotherms of 1 suggest a record-high C3H6 uptake of 34.0/92.4 cm3 cm–3 (0.01/0.1 bar) at 298 K. In situ spectroscopies, crystallographic experiments, and modeling have jointly elucidated that the outstanding propylene uptakes at lower pressure are dominated by multiple binding interactions and swift diffusion behavior, yielding quasi-orthogonal configuration of propylene in adaptive channels. Breakthrough tests demonstrate that 30.8 L of propylene with a serviceable purity of 95.0–99.4% can be accomplished from equimolar C3H6/C3H8 mixtures for 1 kg of activated 1. Such an excellent property is also validated by the breakthrough tests of quinary mixtures containing CH4/C2H4/C2H6/C3H6/C3H8 (3/5/6/42/44, v/v/v/v/v). Particularly, structurally stable 1 can be easily synthesized on the kilogram scale using cheap materials (only $167 for per kilogram of 1), which is important in industrial applications.

Photoluminescence Quenching in Recyclable Water-Soluble Zn-Based Metal–Organic Framework Nanoflakes for Dichromate Sensing

Nanoflakes are materials with high dispersion, a large specific surface area, and a high number of active sites that can provide a good platform for various fluorescence sensors and are very popular among researchers. In this study, a nanoflake-like zinc metal–organic framework (Zn-MOF) was successfully synthesized from the organic ligand 1,2,4,5-tetra(1H-imidazol-1-yl)benzene and zinc nitrate. The synthesized Zn-MOF nanoflakes are extremely soluble in water and exhibit high fluorescence stability. Since Cr2O72– can significantly quench the fluorescence of Zn-MOF aqueous solution, a rapid detection method for Cr2O72– content in water was constructed with a linear range and linear correlation of 0.3–20 μM and 0.992, respectively. The fluorescence quenching constant of the Zn-MOF is KSV = 2.003 × 104 M–1, and the detection limit for Cr2O72– is as low as 0.09 μM. Through the study of fluorescence lifetime and UV absorption, it is proven that the mechanism of Cr2O72– quenching the fluorescence of the Zn-MOF is the inner filter effect. In addition, even after being applied five times, the Zn-MOF still maintained good detection performance for Cr2O72–. The proposed method was successfully applied to the determination of real water samples, confirming that it can be used as an alternative method for the detection of Cr2O72– in environmental samples.

A neutral zinc(II) metal-organic framework with nanoporous channels for efficient and selective absorption of anionic dyes

One porous metal−organic framework {[Zn(TIA)(DPE)0.5]·3DMF}n (Zn-1) was successfully constructed under solvo-thermal reaction of Zn(NO3)2·6H2O with multifunctional ligand 3-(4H-1,2,4-triazol-1-yl)-isophthalic acid (H2TIA) and linear bridge dipyridyl ethylene (DPE). Polymer Zn-1 characters as a (32,4-c net) 3D skeleton containing uni-dimensional channels, which results in its high efficient adsorption behavior of anionic dyes CR2−, MO–, and EBT–. Especially for the large-size CR2−, it shows the most rapid removal rate. More importantly, it realized good separation effects of mixed anionic and cationic dyes (CR2−/MB+ and MO–/MB+). Such excellent performances of dye adsorption and separation are mainly caused by the uni-dimensional channels of MOF Zn-1 and supramolecular interactions between guest-host, which was supported by ab initio molecular dynamics (AIMD) simulations.

A simple, robust, and efficient structural model to predict thermal stability of zinc metal-organic frameworks (Zn-MOFs): The QSPR approach

The thermal stability of MOFs refers to resist degradation of their structure, upon exposure to heat. It may depend on the type of linkers, metal SBUs, metal-ligand interaction, and type of packing of MOF. Many applications of MOF compounds require high thermal stability so that their frameworks do not collapse upon thermal treatment. A straightforward method based on a Quantitative Structure-Property Relationship (QSPR) was established to achieve a precise model to estimate the thermal stability of MOF compounds having zinc SBUs due to their importance in recent researches. The proposed model was developed based on descriptors including the number of nitrogen and zinc atoms, the interactions between heteroatoms of linkers and metal centers, and various molecular fragments. A logarithm of experimental thermal stability (log TS) of 151 MOFs is applied to develop a precise model. The coefficients of determination (R 2 ) for the training and test sets were obtained 0.999 and 1.000, respectively. The Root Mean Square Error for Prediction (RMSEP) of log TS of training and test sets are 0.003 and 0.001, respectively. According to resulted statistical parameters, the novel model is robust and efficient satisfactory. • The thermal stability of metal-organic frameworks (MOFs) is one of the principal concerns for various applications. • A QSPR model was developed to simply predict the relationship between thermal stability and the Zn-MOF SBUs. • The QSPR approach was reliable, robust, and applicable for Zn-MOFs with diverse linkers. • Considering the resulted multilinear regression model, MOF compounds can be well designed with suitable thermal stability. • The presented QSPR model will be developed to estimate other physicochemical properties of MOFs from their experimental data.

Highly selective metal-organic framework-based (MOF-5) separator for non-aqueous redox flow battery

• A facile and scalable process is developed to fabricate separator for NARFB. • The separator achieves 100% materials utilization and excellent repairability. • The separator shows a remarkable ionic selectivity of 26.6 and delivers 99.7% CE. • 0.04% per cycle capacity decay over 200 cycles of the NARFB. Non-aqueous redox flow batteries (NARFBs) are promising in the grid-scale energy storage for the harvesting of the intermittent renewable power sources. However, the lack of efficient separator is still impeding their further development. A flexible nanoporous separator is prepared through a “rolling dough” strategy, with zinc metal-organic framework (MOF-5) and polytetrafluoroethylene as the substrate. The prepared separator shows a remarkable ionic selectivity of Li + over N-(ferrocenylmethyl)-N,N-dimethyl-N-ethylammonium ions (Fc1N112 + ) at a high ratio 26.6. A Li-based hybrid NARFB constructed with the separator exhibits substantially high Coulombic efficiency 99.7% and average discharge capacity 2.26 Ah L −1 with capacity retention 99.96% per cycle over 200 cycles at 4 mA cm −2 . The excellent performance is attributed to the MOF nanoparticles and the designed composite structure, which achieves both high ionic selectivity and chemical stability simultaneously. This work provides a facile and efficient strategy to fabricate high-performance separator for NARFBs.

A fluorescence zinc metal-organic framework for the effective detection of Fe3+ and Fe2+ in water

A novel MOF of Zn-APT can be used as the fluorescence probe to detect Fe 3+ in aqueous solution with the high sensitivity and selectivity. It can absorb hemoporphyrin dihydrochloride on its surface to form red crystal Zn-APT-PH, which can also be used as the fluorescence probe to detect Fe 2+ in aqueous solution with the high sensitivity and selectivity. • A fluorescence metal–organic framework of Zn-APT was synthesized. • Zn-APT has the novel and compact structure with a nbo topology type. • Zn-APT can be used as a fluorescent probe to detect Fe 3+ effectively. • Zn-APT can adsorb hemoporphyrin dihydrochloride to form a red-brown crystal Zn-APT-PH. • Zn-APT-PH can be used as a fluorescent probe to detect Fe 2+ effectively. A fluorescence metal-organic framework [Zn 3 (APT) 4 ]·2H 2 O (Zn-APT) was synthesized from Zn(NO 3 ) 2 ·6H 2 O and 2-amino-6-purinethiol (ATP) by the solvothermal reaction. Zn-APT has a novel compact structure with a nbo topology type. The analyses of single-crystal diffraction reveal that Zn-APT crystallizes in a cubic crystal system and F d 3 ¯ c space group. Based on a large amount of π-conjugated organic ligands of ATP and d 10 metal center of Zn 2+ , Zn-APT can emit strong luminescence. It can be used as a fluorescent probe to detect Fe 3+ ion effectively. The detection limit is 0.28 μM and K sv (quenching efficiency) is 2.1 × 10 4 M −1 . In addition, Zn-APT can adsorb hemoporphyrin dihydrochloride to produce a red-brown crystal Zn-APT-PH. Interestingly, it can also be used to detect Fe 2+ ion efficiently with the detection limit of 0.12 μM and K sv of 1.9 × 10 4 M −1 .

Stable zinc metal-organic framework as efficient bifunctional fluorescent probe for selective detection of nitrobenzene and Fe(Ⅲ)

Through a solvothermal approach, a new zinc metal-organic framework (Zn-MOF), [Zn(PBA)(pic)(H2O)]·H2O·0.5DMA has been successfully engineered, based on 2-picolinic acid (Hpic) and 4-(pyridin-4-yl) benzoic acid (HPBA) ligands. We investigated the crystalline structure, chemical and thermal stability, and fluorescence properties by some modern techniques in detail. Zn-MOF possesses splendid water stability. Especially, the Zn-MOF displays remarkable fluorescent quenching effect toward nitrobenzene (NB) and Fe3+ ion. The high sensitivities KSV values for NB and Fe3+ are 3.80 ​× ​103 ​M−1, and 2.42 ​× ​104 ​M−1, and the low limit of detection values of NB and Fe3+ are 1.84 ​× ​10−5 ​M and 0.315 ​μM. Moreover, the electron and energy transfer mechanism are reasonably explained for the sensing mechanisms. As a result, Zn-MOF can be used as a dual-responsive luminescence quenching detector to detect NB and Fe3+ with outstanding sensitivity, selectivity and recyclability.

Controllable synthesis of nickel doped hierarchical zinc MOF with tunable morphologies for enhanced supercapability

Metal-organic frameworks (MOFs) are attracting tremendous research interest because of their rich redox sites and high specific area which are beneficial for the energy storage applications. Nevertheless, the poor conductivity, low mechanical strength and unsatisfactory capacity severely hinder their wide application. Hence, it is of practical significance to design highly efficient and facile strategy to solve these issues. Herein, vertically oriented ZnO nanorod arrays are applied as precursor to synthesize laminated scale-like and highly-oriented Ni/Zn-MOF/ZnO nanocomposite. Owing to the desirable conductivity resulting from the doping nickel ions and the interaction between ZnO and its relative MOF, the fabricated 0.3Ni/Zn-MOF/ZnO@CC electrode exhibits an electrochemical capacitance of 1693 mF cm−2 at 1 mA cm−2. Moreover, the electrochemical capacitance retention of 80.7 % after 2500 cycling numbers is obtained under the constant current density of 10 mA cm−2 and the low internal resistance Rs of 0.89 Ω is observed. For practical application, the as-synthesized laminated scale-like Ni/Zn-MOF/ZnO@CC nanocomposite is served as positive electrode to fabricate solid-state asymmetric supercapacitor device. Moreover, a 2.5 V indicator could be powered for 8 min when the prepared supercapacitor units are connected. This work demonstrates the promising potential of the synthesized scale-like Ni/Zn-MOF composites for electrochemical energy storage applications.

Solvo-thermal synthesis of a unique cluster-based nano-porous zinc(II) luminescent metal-organic framework for highly sensitive detection of anthrax biomarker and dichromate

In this work a flexible multi-dentate 4,4′-(1H-1,2,4-triazole-1-yl) methylene-bis(benzonic acid) (H2L) ligand has been employed, a unique cluster-based nano-porous luminescent zinc(II) metal-organic framework {[Zn(μ6-L)]·(DMAC)2}n (1) (DMAC = Dimethylacetamide) has been isolated under solvo-thermal conditions. The H2L ligand adopts hexa-dentate coordination modes via one triazole nitrogen atom and four aromatic carboxylate oxygen atoms, which bridge the neighboring six-coordinated ZnII centers, leading to a three-dimensional (3D) nano-porous metal organic framework. A PLATON program analysis suggests the total potential solvent area volume is 2028.9 Å3, which occupy 62.5% percent of the unit cell volume (3248.4 Å3). PXRD Patterns of the as-synthesized samples 1 have been determined confirming the purity of the bulky samples. Photo-luminescent properties indicate strong fluorescent emissions of 1 at the room temperature. Further photo-luminescent measurements show that 1 can exhibit highly sensitive real-time luminescence sensing of anthrax biomarker dipicolinic acid (DPA) with high quenching efficiency (KSV = 1.48 × 105 M−1) and low detection limit (0.298 μM (S/N = 3)). Meanwhile 1 also exhibits highly selective and sensitive luminescence sensing for Cr2O72- ions in aqueous solutions with high quenching efficiency KSV = 1.22 × 104 L·mol−1 and low detection limit (0.023 μM (S/N = 3)). Therefore 1 can be used a unique multi-functional 3D cluster-based metal organic material in sensitive detection and effective detection of environment pollutants and biomarker molecules.

Superlow Dosage of Intrinsically Bioactive Zinc Metal-Organic Frameworks to Modulate Endothelial Cell Morphogenesis and Significantly Rescue Ischemic Disease.

Despite long-term efforts for ischemia therapy, proangiogenic drugs hardly satisfy therapy/safety/cost/mass production multiple evaluations and meanwhile with a desire to minimize dosages, thereby clinical applications have been severely hampered. Recently, metal ion-based therapy has emerged as an effective strategy. Herein, intrinsically bioactive Zn metal-organic frameworks (MOFs) were explored by bridging the dual superiorities of proangiogenic Zn2+ and facile/cost-effective/scalable MOFs. Zn-MOFs could enhance the morphogenesis of vascular endothelial cells (ECs) via the PI3K/Akt/eNOS pathway. However, high dosage is inevitable and Zn-MOFs suffer from insolubility and low stability, which lead to the bioaccumulation of Zn-MOFs and seriously potential toxicity risks. To alleviate this, it is required to decrease the dosage, but this can be entrapped into the dosage/therapy/safety contradiction and disappointing therapy effect. To address these challenges, the bioavailability of Zn-MOFs is urgent to improve for the minimization of dosage and significant therapy/safety. The mitochondrial respiratory chain is Zn2+ active, which inspired us to codecorate EC-targeted and mitochondria-localizing-sequence peptides onto Zn-MOF surfaces. Interestingly, after codecoration, a 100-fold reduced dosage acquired equally powerful vascularization, and the superlow dosage significantly rescued ischemia (4.4 μg kg-1, about one order of magnitude lower than the published minimal value). Additionally, no obvious muscle injury was found after treatment. Potential toxicity risks were alleviated, benefiting from the superlow dosage. This advanced drug simultaneously satisfied comprehensive evaluations and dosage minimization. This work utilizes engineering thought to rationally design "all-around" bioactive MOFs and is expected to be applied for ischemia treatment.

Coupling Postsynthetic High-Temperature Oxidative Thermolysis and Thermal Rearrangements in Isoreticular Zinc MOFs.

Herein, we report coupling in situ high temperature postsynthetic modifications (PSMs) in metal-organic frameworks (MOFs). Thermo-reactive propargyloxy-functionalized zinc IRMOFs (isoreticular metal-organic frameworks) prepared from 2-(prop-2-yn-1-yloxy)-[1,1'-biphenyl]-4,4'-dicarboxylic acid (H2bpdcOCH2CCH) were investigated for their high-temperature postsynthetic rearrangement (PSR) chemistry to heterocyclic chromenes and benzofurans and then coupled to solid-gas reactions with molecular oxygen. The selectivity for the initial molecular rearrangements was found to be inverted in the porous MOF environment compared to conventional melt reactions of the ester compound Me2bpdcOCH2CCH and proceeded far more easily than the solid-state transformation from H2bpdcOCH2CCH, showing the potential of MOFs to give rise to different chemistry. The major oxidative process was thermolysis of the chromene ring with a minor pathway of allylic-type oxidation to give heterocyclic chromenone functionality. The sequence was also successful on a series of two-component multivariate IRMOF frameworks prepared from thermo-reactive H2bpdcOCH2CCH and thermo-resistant H2bpdcOMe linkers, demonstrating that these reactions can be used with known crystal engineering strategies. All transformations were fully compatible with the requirements to maintain MOF crystallinity and porosity as evidenced by surface area analysis and X-ray powder diffraction measurements. This work contributes to establishing the feasibility of high-temperature solid-gas manifolds for MOF PSM.

A new three-dimensional zinc(II) metal-organic framework as a fluorescence sensor for sensing the biomarker 3-nitrotyrosine.

3-Nitrotyrosine (3-NT), an oxidative stress biomarker, is closely associated with various diseases. Thus, rapid and sensitive detection of 3-NT is of great significance for preventing and treating diseases. Herein, we reported a new 3D zinc-based metal-organic framework (Zn-MOF) [Zn(L)(HBTC)] (L = (E)-4,4'-(ethene-1,2-diyl)bis[(N-pyridin-3-yl)benzamide], H3BTC = 1,3,5-benzenetricarboxylic acid), which was structurally characterized by single crystal X-ray diffraction, IR, PXRD and TG. The Zn-MOF can be used as a highly efficient fluorescence sensing material to provide a direct and low-cost method for the rapid detection of 3-NT and shows high sensitivity with a KSV value of 6.596 × 104 M-1, a rapid luminescence response within 24 s, excellent selectivity, high anti-interference ability and good recyclability. It is the first example of a MOF being used to directly detect 3-NT as a luminescence sensor to our knowledge. The sensing mechanism of the Zn-MOF towards 3-NT is discussed in detail, which provides a basis for the rational design of MOF sensing materials and their application in biomarker detection.

Stable Zinc Metal Organic Framework as Efficient Bifunctional Fluorescent Probe for Selective Detection of Nitrobenzene and Fe(III)

Stable Zinc Metal Organic Framework as Efficient Bifunctional Fluorescent Probe for Selective Detection of Nitrobenzene and Fe(III)

Enhancing K2S2O8 electrochemiluminescence based on silver nanoparticles and zinc metal-organic framework composite (AgNPs@ZnMOF) for the determination of l-cysteine.

A silver nanoparticle-doped Zn(ii) metal–organic framework composite (AgNPs@ZnMOF) was investigated as an electrochemiluminescence (ECL) signal enhancer for potassium persulfate. First, ZnMOF was prepared by a one-step hydrothermal method, and then AgNPs@ZnMOF composite was obtained by depositing AgNPs on the surface and interior of ZnMOF. After the AgNPs@ZnMOF composite was modified on the glass carbon electrode (GCE), the cathode luminescence of potassium persulfate on bare GCE was enhanced by 8 times. A dual amplification mechanism provided by Zn(ii) and Ag nanoparticles in the AgNPs@ZnMOF composite has been validated by ECL spectra, fluorescence spectra, and electrochemical methods. The interaction between the sulfhydryl groups in l-cysteine (l-Cys) and AgNPs significantly affects the catalytic luminescence of the AgNPs@ZnMOF composite. Thus, a sensitive ECL method for the determination of l-Cys was developed based on the inhibition effect of l-Cys on the ECL signal within the linear range from 5.0 nM to 1.0 μM and the limit of detection was found to be 2 nM (S/N = 3). The established method has been successfully applied to the determination of l-Cys in human urine.

Selective and fast growth of CdS nanocrystals on zinc (II) metal–organic framework architectures for photoelectrochemical response and electrochemical immunosensor of foot-and-mouth disease virus

The integration of cadmium sulfide (CdS) and metal organic frameworks (MOFs) has shown promise in applications such as photocatalysis and sensing. Herein, a sensitive electrochemical immunosensor based on a room temperature, simple and fast aqueous synthetic strategy of in-situ selective growth nanocystalline CdS on zinc metal organic framework (CdS@Zn-MOF) is reported. We investigated the possibility of growth CdS on various MOFs, synthesizing by electrosynthesis or solution phase syntheses with different metal ions (e.g. Zn2+, Cu2+, Fe3+, Co2+, Zr4+) and organic ligands (e.g. 1,3,5-benzenetricarboxylic acid, 2-methylimidazole, 1,4-benzenedicarboxylic acid, 2-aminoterephthalic acid). This simple experiment process proved that CdS nanocrystalline can selectively grow on varied structures Zn-MOFs with different organic ligands. The synthesis, characterization and mechanisms involved in the formation of this composite material was explored carefully and thoroughly. The unique properties of this composite presented a promising photoelectrochemical and electrochemical applications. Therefore, a sensitive Zn-MOF-labeled amperometric immunosensor based on this strategy for the detection of foot-and-mouth disease virus (FMDV) was developed. The logarithm FMDV concentration was range from 0.5 fg mL−1 to 5 ng mL−1 with a low detection limit of 0.05 fg mL−1. Moreover, this proposed sensor with good selectivity, acceptable reproducibility, and stability was successfully applied to detect FMDV in actual blood sample. Furthermore, this method of growth the CdS nanocrystalline in situ on a Zn-MOF device structure or platform also provides a new horizon for future optoelectronic applications.

Zinc-Metal Organic Frameworks: A Coreactant-free Electrochemiluminescence Luminophore for Ratiometric Detection of miRNA-133a.

Developing a coreactant-free ratiometric electrochemiluminescence (ECL) strategy based on a single luminophore to achieve more accurate and sensitive microRNA (miRNA) detection is highly desired. Herein, utilizing zinc-metal organic frameworks (Zn-MOFs) as the single luminophore, a novel dual-potential ratiometric ECL biosensor was constructed for ultrasensitive detection of miRNA-133a. The as-prepared Zn-MOFs exhibited simultaneous cathode and anode ECL emission. Furthermore, the Zn-MOFs were confirmed to be a multichannel ECL sensing platform with excellent annihilation and coreactant ECL emission. The corresponding ECL behaviors were investigated in detail. Benefiting from the hybridization chain reaction (HCR) amplification technology, N,N-diethylethylenediamine (DEAEA) was modified on hairpin DNA, and the gained products loaded with quantities of DEAEA enhanced the anodic ECL intensity of Zn-MOFs. In the presence of miRNA-133a, the ECL intensity ratio of anode to cathode (Ia/Ic) was significantly increased, which realized the ultrasensitive ratiometric detection of miRNA-133a. In addition, without an exogenous coreactant, the biosensor revealed superb accuracy and stability. Under optimal conditions, the detection linearity of miRNA-133a was from 50 aM to 50 fM with a low detection limit of 35.8 aM (S/N = 3). This is the first work to use Zn-MOFs as a single emitter for reliable ratiometric ECL bioanalysis, which provides a new perspective for fabricating a ratiometric ECL biosensor platform.

A hydrolytically stable amino-functionalized Zinc(II) metal-organic framework containing nanocages for selective gas adsorption and luminescent sensing

To achieve the selectivity of luminescent sensing and gas separation, an unprecedented nanocages based 3D amino-functionalized MOF, {(Me 2 NH 2 )[Zn(NH 2 -TCB)]} n ( ZnMOF ) was constructed through ligand pre-design strategy. ZnMOF contains a unique 1D triple [Zn(COO)] n helix chain SBU and forms 7.89 × 11.72 × 14.79 Å 3 nanocages with the porosity up to 42.9%. Benefit from the outstanding thermal and chemical stabilities, the ZnMOF demonstrates considerable adsorption selectivity for CO 2 /CH 4 and highly sensitive detectability to Cr(VI) anions and nitroimidazole/nitrofuran antibiotics in water. In addition, the high selective adsorption and sensing mechanisms were also explored. Therefore, ZnMOF is a multifunctional material in the efficient gas adsorption and separation, and the detection of Cr(VI) anions and nitroimidazole/nitrofuran antibiotics. An unprecedented nanocages based amino-functionalized ZnMOF shows considerable selectivity in gas adsorption and luminescent sensing for Cr(VI) anions and antibiotics in aqueous media. • An unprecedented amino-functionalized nanocages based ZnMOF was designed with the porosity is 42.9 %. • ZnMOF shows high uptake for N 2 and H 2 and considerable adsorption selectivity for CO 2 /CH 4. • ZnMOF were implemented as dual-responsive luminescent sensors to detect Cr(VI) anions, and antibiotics in water, simultaneously. • The mechanism of selective adsorption and luminescence sensing were investigated.

Anionic zinc(II) metal-organic framework post-synthetically modified by alkali-ion exchange: Synthesis, characterization and hydrogen adsorption properties

An anionic metal-organic framework with rutile topology was prepared and post-synthetically modified. DMA ions in the channels were exchanged by alkali ions (Li+, Na+, K+, Rb+ and Cs+) and prepared materials were characterized by elemental analysis, scanning electron microscopy, infrared spectroscopy, thermogravimetry and powder X-ray diffraction. The successful ion exchange process and the amount of ions exchanged were determined by ICP-MS measurements. The ion-exchanged samples were subsequently studied as gas adsorbents for hydrogen.

Synthesis, structure and fluorescence property of a new Zn-MOF based on a tetraphenylethane (TPE) ligand

A new 3D luminescent Zinc (II) metal-organic framework, has been solvothermally synthesized by using Zn(NO3)2⋅4H2O and a mixture of ligands: Titpe ligand and bcpf ligand. The molecular formula is [Zn(Titpe)(bcpf)•(DMF)]n, (Compound 1, Titpe = 1,1,2,2-tetrakis(4-(1H-imidazol-1-yl)phenyl)ethane, bcpf= 4,4΄-sulfonyldibenzoic acid). Compound 1 crystallizes in the triclinic system, space group P -1, with a=12.9990(9), b=14.2181(10), c=14.3781(10) Å, α = 89.974(4)°, β = 71.640(4)°, γ = 80.732(4)°, V = 2485.6(3) Å3, Z = 2, Mr = 1039.43, Dc =1.389 g/cm3, μ = 0.600 mm−1, F(000) = 1076.0, R = 0.0747 and wR =0.2508 for 9724 observed reflections (I > 2σ(I)). Topology analysis shows that compound 1 is a double interpenetrating structure. In addition, due to the ligand-to-ligand charge transfer of the TPE chromophore, luminescent spectra of 1 shows that it emits strong blue light. Compound 1 can detect Fe3+ ions with high selectivity and sensitivity among diverse inorganic cations in aqueous solution and is also a highly selective sensing material for CrO42− and Cr2O72- ions.

Hierarchical hollow microspheres of carbon nanorods with enhanced supercapacitor performance

A hierarchical hollow microsphere of carbon nanorods (HHMCNs) is constructed via facile carbonization for a hollow microsphere consisted of zinc metal-organic framework (Zn-MOF-74) nanorods. The spherical Zn-MOF-74 nanorods with a chestnut-like morphology are formed through a hydrothermal reaction of crystalline Zn-MOF-74 nanoparticles. When the HHMCNs carbonized at 900 °C, the obtained HHMCNs-900 possesses a ultrahigh specific surface area (SBET = 2249 m2 g−1), large pore volume with a hierarchical porosity (2.5 cm3 g−1), and an ideal oxygen content (5.1 at.%). Using the HHMCNs-900 as a supercapacitor electrode delivers a satisfying specific capacitance (287 F g−1 at 0.5 A g−1), excellent rate capability (165 F g−1 at 50 A g−1), superior energy density of 39.86 Wh kg−1 at a power density of 250 W kg−1, and a long-term cycling stability keeping 97 % of its initial capacity after 10 000 cycles at 20 A g−1. Furthermore, a symmetric cell (HHMCNs-900//HHMCNs-900) is assembled and demonstrates unexpected performances, showing a satisfying specific capacity (∼55 F g−1 at 0.1 A g−1), impressive rate capability (∼44 F g−1 at 5.0 A g−1), and superior stability with a capacitance retention of ∼95.3 % over 10 000 cycles at 10 A g−1. These remarkable electrochemical performances suggest that the hierarchical hollow microsphere of carbon nanorods (HHMCNs) is an ideal electrode material for supercapacitors.