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Quantum size effect usually causes energy level splitting and band broadening as material size decreases. However, this may change again by the surface adsorbents, doping and defects, which rarely attracts much attention. Herein, CdWO 4 sub-1 nm nanowires (SNWs) with oleylamine adsorption, PO 4 3- -doping and oxygen defects are synthesized by combining Cd(CH 3 COO) 2 , H 3 PW 12 O 40 (PW 12 ) and oleylamine (abbreviated as PO 4 3- -CdWO 4 -X SNWs). Compared with bulk CdWO 4 , they exhibit unexpected absorption spectra (extended from 292 nm to 453 nm) and band gap (reduced from 4.25 eV to 2.74 eV), thus bringing remarkable visible-light CO 2 photoreduction activity. Under 410 nm LED light irradiation, PO 4 3- -CdWO 4 -40 SNWs exhibit the highest photocatalytic performance with a CO 2 -to-CO generation rate of 1685 μmol g -1  h -1 . Density functional theory (DFT) calculations demonstrate the adsorbed oleylamine raises the valence band and enhances the adsorption of reaction substrate and intermediates, thus decreasing their reduction energy barriers. Furthermore, PO 4 3- -doping and oxygen defects will generate defect energy band below the conduction band of PO 4 3- -CdWO 4 -40 SNWs, resulting in remarkable visible light absorption and superior photocatalytic CO 2 reduction performance. This work highlights the significant impacts of surface adsorbents, doping and defects on the physicochemical and catalytic properties of sub-nano materials., (© 2024 Wiley-VCH GmbH.)

Metal-oxo clusters show great promise in lithium ion battery applications as anode materials by virtue of their native nature of well-defined nanostructures and multielectron redox activities. However, their intrinsic unsatisfactory electrical conductivity and tendency to aggregation make them difficult to fully utilize. Herein, a well-dispersed Mn 12 O 12 (CH 3 COO) 16 (H 2 O) 4 (denoted as Mn 12 ) cluster is constructed by rationally adopting carbon dots (CDs) with nanosize and high conductivity as stabilizers. Thanks to the fully exposed redox sites of Mn 12 clusters and additional interfacial energy storage mechanism, the optimized Mn 12 /CDs-1:20 anode delivers a high specific capacity of 1643 mAh g -1 at 0.2 A g -1 (0.25 C) and exhibits outstanding rate and cycling capabilities. This paper provides a green and efficient paradigm to synthesize well-dispersed manganese-oxo clusters for the first time and builds a new platform for cluster-based energy storage.

Developing highly efficient, stable, and cost-effective two-dimensional (2D) conjugated polymers (CPs) for overall water splitting (OWS) is critical for producing clean and renewable hydrogen energy, yet it remains a great challenge. Here, we designed eight 2D CPs through the topological assembly of diacetylene and benzene-derived molecular linkers that can offer active sites for hydrogen and oxygen evolution reactions, and explored their structural, electronic, optical, and photocatalytic OWS properties by performing first-principles computations. It is shown that incorporating benzo-heterocyclic rings into CPs can significantly modulate the electronic structures of CPs and broaden the spectral absorption, suitable for visible-light-driven OWS. Remarkably, through a range of screening criteria, including stability, electronic band structures, band edge alignments, and photocatalytic activity, we found that CP-4 based on diacetylene and benzotrifuran can spontaneously trigger the OWS in a neutral environment under its own light-induced bias, eliminating the need for sacrificial agents or cocatalysts. Specifically, the HER active site is primarily located at diacetylene moieties, while the OER active site is mainly concentrated on the benzo-heterocyclic rings. Moreover, the ideal STH efficiency for OWS on CP-4 was estimated to be 13.87%, highlighting its potential as a prospective photocatalyst for large-scale industrial OWS. Our findings open a door to the rational design of novel polymer photocatalysts for OWS.

Alkaline water splitting is a highly efficient and clean technology for hydrogen energy generation. However, in alkaline solutions, most catalysts suffer from extreme instability. Herein, a cross-nanostructured N, F, and CO 3 2- codoped iron oxyhydroxide composite (N,F-FeO(OH)-CO 3 -NF) rich in oxygen defects is designed for water splitting in the alkaline solution. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations show that the introduction of F and CO 3 2- can induce electron redistribution around the active center Fe, accelerate the four-electron transfer process, and optimize the d-band center, thereby improving the efficiency and stability of HER and OER. In a 1 M KOH solution, N,F-FeO(OH)-CO 3 -NF only needs the overpotential of 248 mV for OER and the overpotential of 199 mV for HER to reach the current density of 10 mA·cm -2 . Meanwhile, it can reach 100 mA·cm -2 current density at 1.55 V vs RHE and maintains a current density of 10 mA·cm -2 for 120 h in a two-electrode electrolytic water device. Compared with bulk hydroxides, the heteroatom and anion codoped composite hydroxides are more stable and have dual functions in the electrolyte solution. This is of great significance for designing a new stable water-splitting electrocatalyst.

The oxygen reduction reaction (ORR) is a key energy conversion process, which is critical for the efficient operation of fuel cells and metal-air batteries. Here, we report the significant enhancement of the ORR-performance of commercial platinum-on-carbon electrocatalysts when operated in aqueous electrolyte solutions (pH 5.6), containing the polyoxoanion [Fe 28 (μ 3 -O) 8 (L-(-)-tart) 16 (CH 3 COO) 24 ] 20- . Mechanistic studies provide initial insights into the performance-improving role of the iron oxide cluster during ORR. Technological deployment of the system is demonstrated by incorporation into a direct formate microfluidic fuel cell (DFMFC), where major performance increases are observed when compared with reference electrolytes. The study provides the first examples of iron oxide clusters in electrochemical energy conversion and storage., (© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

The development of visible-light photocatalysts for the selective oxidative coupling of amines to imines is an area of great interest. Herein, four hybrid compounds based on polyoxometalate anions and tris(bipyridine)ruthenium cations, Ru(bpy) 3 [M 6 O 19 ] (M = Mo, W) 1 - 2 , [Ru(bpy) 3 ] 2 [Mo 8 O 26 ] 3 , [Ru(bpy) 3 ] 2 [W 10 O 32 ] 4 , are prepared and characterized by X-ray diffraction (single-crystal and powder), elemental analysis, energy-dispersive X-ray spectroscopy (EDS) analysis, infrared (IR) spectroscopy, and solid diffuse reflective spectroscopy. Single-crystal structural analysis indicates that polyoxometalate anions and tris(bipyridine)ruthenium cations interact with each other through extensive hydrogen bonds in these compounds. These hybrid species with strong visible-light-harvesting abilities and suitable photocatalytic energy potentials show excellent photocatalytic activity and selectivity for the oxidation of amines to imines at room temperature in air as an oxidant. Among them, compound 1 with the [Mo 6 O 19 ] 2- anion has the highest catalytic activity, which can swiftly convert >99.0% of benzylamine into N-benzylidenebenzylamine with a selectivity of 98.0% in 25 min illumination by a 10 W 445 nm light-emitting diode (LED). Its turnover frequency reaches 392 h -1 , which is not only better than the homogeneous catalyst [Ru(bpy) 3 ]Cl 2 but also much superior to those achieved over most of reported heterogeneous catalysts. Moreover, it shows a wide generality for various aromatic amines, accompanied by the advantages of good recyclability and stability. The photocatalytic oxidation mechanism of amines to the corresponding imines over polyoxometalate-based hybrid compounds was fully investigated.

Four polyoxometalate (POM)-based organic-inorganic hybrid compounds, namely, (H 2 bimb) 6 H 8 [((Mn(H 2 O) 3 (μ-bimb)) 0.5 (Mn(H 2 O) 4 )(Mn(H 2 O) 5 ) 0.5 (AgP 5 W 30 O 110 )) 2 ]·29H 2 O ( 1 ), [(Cu(Hbimb)(H 2 O) 2 (μ-bimb)Cu(Hbimb)(H 2 O))(Cu(H 2 O) 2 (μ-bimb)Cu(H 2 O) 3 )((Cu(H 2 O) 2 ) 0.5 (μ-bimb)(Cu(H 2 O) 3 ) 0.5 )H 2 (AgP 5 W 30 O 110 )]·12.5H 2 O ( 2 ), (H 2 bimb) 2 H[(Zn(Hbimb)(H 2 O) 4 (Zn(Hbimb)(H 2 O) 2 ) 0.5 ) 2 (AgP 5 W 30 O 110 )]·12H 2 O ( 3 ), and (H 2 bimb) 3 H 2 [(Ag(H 2 O) 2 ) 0.5 (Ag(Hbimb)Ag(Hbimb)(μ-bimb)Ag)(Ag(H 2 O) 2 ) 0.5 (AgP 5 W 30 O 110 )]·7H 2 O ( 4 ) (bimb = 1,4-bis(1H-imidazol-1-yl)benzene), were hydrothermally synthesized using a silver-centered Preyssler-type POM K 14 [AgP 5 W 30 O 110 ]·18H 2 O (abbreviated as K-{AgP 5 W 30 }) as a precursor. In 1 - 4 , {AgP 5 W 30 } clusters integrating the merits of Ag + and {P 5 W 30 } units are modified by different transition metal (TM)-organic fragments to extend the structures into three-dimensional frameworks. As nonenzymatic electrochemical sensor materials, 1 - 4 show good electrocatalytic activity, high sensitivity, and a low detection limit for detecting hydrogen peroxide (H 2 O 2 ); 4 possesses the highest sensitivity of 195.47 μA·mM -1 ·cm -2 for H 2 O 2 detection. Most importantly, the average level of H 2 O 2 detection of these {AgP 5 W 30 }-based materials outperforms that of Na-centered Preyssler-type {NaP 5 W 30 } and most Keggin-type POM-based materials. The performances of such {AgP 5 W 30 } materials mainly stem from the unique advantage of high-negatively charged {AgP 5 W 30 } clusters together with the good synergistic effect between {AgP 5 W 30 } and TMs. This work expands on the research of high-efficiency POM-based nonenzymatic electrochemical H 2 O 2 sensors using Ag-containing POMs with high negative charges, which is also of great theoretical and practical significance to carry out health monitoring and environmental analysis.

Noble metal nanoparticles (NMNPs) with excellent catalytic activity and stability play an important role in the field of environmental governance. A uniform distribution and a strong binding force with the carriers of the noble metal nanoparticles are important, but avoidance of the use of additional reducing agents is a promising direction of research. Herein, 2D ultrathin surfactant-encapsulating polyoxometalate (SEP) nanosheets constructed by the self-assembly of dodecyldimethylammonium bromide (DODA) and molybdophosphate (H3PMo12O40, PMo12) are designed to be versatile carriers for Ag nanoparticles. Under the synergistic effect of the well-arranged PMo12 units, encapsulating hydrophobic oleic acid (OA) and reductive molybdophosphate under Xe lamp irradiation, the silver oleate (AgOA)-derived Ag nanoparticles (5 ± 2 nm) are monodispersed on the DODA-PMo12 assemblies and form the Agx/DODA-PMo12 composite. The optimized Ag4.89/DODA-PMo12 composite exhibits high catalytic activity and stability in the degradation of 4-nitrophenol (4-NP), which reaches a superior rate constant of 6.49 × 10-3 s-1 and without significant deterioration after three recycles. This technique can be facilely promoted to other noble metal nanoparticles with excellent catalytic activity and stability.

The reasonable construction of heterojunction photocatalysts with clear nanostructures and a good interface contact especially the one-dimensional/two-dimensional (1D/2D) composite heterojunction with unique morphology is considered one of the most effective strategies for designing highly efficient photocatalysts. Herein, a series of the 1D β-keto-enamine-based covalent organic framework (COF)/2D g-C 3 N 4 composite materials COF-CN (1: x ; where 1: x represents the mass ratio of COF and g-C 3 N 4 , x = 2.5, 5, 10, 15, 20) is prepared through the in situ reaction of 2,4,6-triformylphloroglucinol (Tp) and benzidine (BD) in stripped g-C 3 N 4 suspension. A series of characterizations, such as X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), have verified their 1D/2D heterojunction structure. With the introduction of 1D COF nanobelts, the absorption of the composite is largely extended to 560 nm. Photocatalytic experiments reveal that the composite COF/CN shows evidently superior photocatalytic performance than individual COF and g-C 3 N 4 . The optimized COF-CN (1:10) exhibits a H 2 production rate of 12.8 mmol g -1 ·h -1 under visible-light (λ ≥ 420 nm) irradiation, which is about 62 and 284 times higher than those of COF and g-C 3 N 4 , respectively. The apparent quantum efficiency (AQE) of COF-CN (1:10) is about 15.09% under 500 nm light irradiation, which is one of the highest among previous COF- or g-C 3 N 4 -based materials. This work provides important strategies for designing and constructing high-efficiency heterojunction photocatalysts with multidimensional features.

The photocatalytic reduction of N 2 to NH 3 is considered a promising strategy to alleviate human need for accessible nitrogen and environmental pollution, for which developing a photocatalyst is an effective method to complete the transformation of this process. We firstly design a series of highly efficient and stable polyoxometalates (POMs)-based zeolitic imidazolate framework-67 (ZIF-67) photocatalysts for N 2 reduction. ZIF-67 can effectively fix N 2 owing to its porosity. Integration of POMs cluster contributes enormous advantages in terms of broadening the absorption spectrum to improve sunlight utilization, enhance the stability of the materials, effectively inhibit the recombination of photo-generated electron-hole pairs, and reduce charge-transfer impedance. POMs can absorb light to convert into reduced POMs, which have stronger reducing ability to provide ample electrons to reduce N 2 . The reduced POMs can recover their oxidation state through contact with an oxidant, which forms a self-recoverable and recyclable photocatalytic fixing N 2 system. The photocatalytic activity enhances with the increasing number V substitutions in the POMs. Satisfactorily, ZIF-67@K 11 [PMo 4 V 8 O 40 ] (PMo 4 V 8 ) displays the most significant photocatalytic N 2 activity with a NH 3 yield of 149.0 μmol L -1  h -1 , which is improved by 83.5 % (ZIF-67) and 78.9 % (PMo 4 V 8 ). The introduction of POMs provides new insights for the design of high-performance photocatalyst nanomaterials to reduce N 2 ., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The electrocatalytic carbon dioxide (CO 2 ) reduction reaction (CO 2 RR) involves a variety of electron transfer pathways, resulting in poor reaction selectivity, limiting its use to meet future energy requirements. Polyoxometalates (POMs) can both store and release multiple electrons in the electrochemical process, and this is expected to be an ideal "electron switch" to match with catalytically active species, realize electron transfer modulation and promote the activity and selectivity of the electrocatalytic CO 2 RR. Herein, we report a series of new POM-based manganese-carbonyl (MnL) composite CO 2 reduction electrocatalysts, whereby SiW 12 -MnL exhibits the most remarkable activity and selectivity for CO 2 RR to CO, resulting in an increase in the faradaic efficiency (FE) from 65% (MnL) to a record-value of 95% in aqueous electrolyte. A series of control electrochemical experiments, photoluminescence spectroscopy (PL), transient photovoltage (TPV) experiments, and density functional theory (DFT) calculations revealed that POMs act as electronic regulators to control the electron transfer process from POM to MnL units during the electrochemical reaction, enhancing the selectivity of the CO 2 RR to CO and depressing the competitive hydrogen evolution reaction (HER). This work demonstrates the significance of electron transfer modulation in the CO 2 RR and suggests a new idea for the design of efficient electrocatalysts towards CO 2 RR., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The oxidized platinum (Pt) can exhibit better electrocatalytic activity than metallic Pt 0 in the hydrogen evolution reaction (HER), which has aroused great interest in exploring the role of oxygen in Pt-based catalysts. Herein, we select two structurally well-defined polyoxometalates Na 5 [H 3 Pt (IV) W 6 O 24 ] (PtW 6 O 24 ) and Na 3 K 5 [Pt (II) 2 (W 5 O 18 ) 2 ] (Pt 2 (W 5 O 18 ) 2 ) as the platinum oxide model to investigate the HER performance. Electrocatalytic experiments show the mass activities of PtW 6 O 24 /C and Pt 2 (W 5 O 18 ) 2 /C are 20.175 A mg -1 and 10.976 A mg -1 at 77 mV, respectively, which are better than that of commercial 20% Pt/C (0.398 A mg -1 ). The in situ synchrotron radiation experiments and DFT calculations suggest that the elongated Pt-O bond acts as the active site during the HER process, which can accelerate the coupling of proton and electron and the rapid release of H 2 . This work complements the knowledge boundary of Pt-based electrocatalytic HER, and suggests another way to update the state-of-the-art electrocatalyst.

The nitrogen (N 2 ) reduction to generate ammonia (NH 3 ) is a prerequisite for inputting fixed nitrogen (N) into a global biogeochemical cycle. Developing highly efficient photocatalysts for N 2 fixation under mild conditions is still a challenge. Herein, we first report three kinds of reduction states of graphene oxide (GO)@polyoxometalate (POM) composite nanomaterials, which have outstanding photocatalytic N 2 fixation activities in pure water without any other electronic sacrificial agents and cocatalysts at atmospheric pressure and room temperature. A lot of experiments show that the remarkable photocatalytic N 2 fixation performance of these three nanocatalysts is due to three factors that doping the reduced POMs (also called heteropoly blues) into the reduce GO (rGO) reduces the aggregation state of rGO (from 5 to 2 nm), resulting in rGO exposing many active sites to enhance the N 2 adsorption amount, these three nanocatalysts possess a wide absorption spectrum and strong reducibility, which facilitate absorb light energy exciting abundant photoelectrons to activate N 2 , and rGO can effectively suppress the electrons recombination and rapidly transfer electrons to the absorbed N 2 to accelerate NH 3 production. Among them, r-GO@H 5 [PMo 10 V 2 O 40 ] (PMo 10 V 2 ) exhibits the highest NH 3 generation efficiency of 130.3 μmol L -1 h -1 , which is improved by 65.9 and 97.3% compared to the reduced PMo 10 V 2 (rPMo 10 V 2 ) and PMo 10 V 2 . Introduction of POMs provides a new perspective in the design of high-performance photocatalytic N 2 fixation nanomaterials.

OER is the key step to increase the rate of water-splitting reaction. Design and construction of appropriate defects is an effective strategy to enhance catalytic activity. Mn has stronger e - -e - repulsion by the local influence of its 3d orbital electrons. When Mn(iii) was successfully introduced into two dimensional F-doped Ni(OH) 2 , it can tune the surface electronic structure of the F-doped Ni(OH) 2 to increase its oxygen deficiency content. In this work, the as-synthesized Mn and F co-doped Ni(OH) 2 -NF on Ni foam (Mn-F/Ni(OH) 2 -NF) shows remarkable oxygen evolution performance, exhibiting 233 mV overpotential at 20 mA cm -2 , and the Tafel slope is 56.9 mV dec -1 in 1 M KOH. The performance is better than that of the same loading of IrO 2 on Ni foam. Density functional theory (DFT) calculations further show that the introduction of oxygen defects can significantly improve the OER catalytic performance of Mn-F/Ni(OH) 2 -NF., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Dye-sensitized solar cells (DSSCs) are the third generation of photovoltaic cells developed by Grätzel and O'Regan. They have the characteristics of low cost, simple manufacturing process, tunable optical properties, and higher photoelectric conversion efficiency (PCE). With an ever increasing energy crisis, there is an urgent need to develop highly efficient, environmentally benign, and energy-saving cell materials. Polyoxometalates (POMs), a kind of molecular inorganic quasi-semiconductor, are promising candidates for use in different parts of DSSCs due to their excellent photosensitivity, redox, and catalytic properties, as well as their relative stability. Following a brief introduction to the development of DSSCs and the potential virtues of POMs in DSSCs, we attempt to make some generalizations about the energy level regulation of POMs that is the underlying theoretical basis for their application in DSSCs, and then we summarize the research progress of POMs in DSSCs in recent years. This is organized in terms of the properties of POMs, namely, electron acceptor, photosensitivity, redox and catalysis, based on the accumulation of our research into POMs over many years. Meanwhile, in view of the fact that the properties of POMs depend primarily on their electronic structural diversity, we keep this point in mind throughout the article with a view to revealing their structure-property relationships. Finally we provide a short summary and remarks on the future outlook. This review may be of interest to synthetic chemists devoted to designing POMs with specific structures, and researchers engaged in the extension of POMs to photoelectric materials.

Based on the MODIS surface reflectance data, five vegetation indices, including norma-lized difference vegetation index (NDVI), simple ratio index (SR), Gitelson green index (GI), enhanced vegetation index (EVI) and soil adjusted vegetation index (SAVI) were constructed as remote sensing variables, coupled with the seven original spectral reflectance bands of MODIS. Stepwise regression and correlation analysis were used to select the variables, and the stepwise regression and Back Propagation (BP) neural network models were constructed based on the measured LAI to retrieve the LAI time series data of Phyllostachys praecox (Lei bamboo) forest during the period from January 2014 to March 2017. The retrieval results were compared with MOD15A2 LAI products during the same period. The results showed that SR was the single variable selected for the stepwise regression model. The correlations of LAI with bands b 1 , b 2 , b 3 , b 7 and five vegetation indices were significant, which could be used as input variables of BP neural network model. There was a significant correlation between the LAI estimated from BP neural network and measured LAI, with the R 2 of 0.71, RMSE of 0.34, and RMSE r of 13.6%. R 2 was increased by 10.9%, RMSE decreased by 5.6%, and RMSE r decreased by 12.3% compared with LAI estimated from stepwise regression method. R 2 was increased by 54.5%, RMSE decreased by 79.3%, and RMSE r decreased by 79.1% compared with MODIS LAI. The LAI of Lei bamboo forest could be accurately retrieved using BP neural network method based on MODIS reflectance time series data, which would be a feasible method for rapid monitoring of LAI in Lei bamboo forest.

A environment-friendly 3D inorganic heteropoly blue (HPB) Ba 2 Na 2 [HPW V 4 W VI 8 O 40 ]·26H 2 O was directly synthesized by hydrothermal method and characterized by means of ICP, IR, XPS, X-ray single crystal and X-ray powder diffraction. It was an efficient heterogeneous photo-Fenton-like catalyst to degrade anionic dye methyl orange under visible light irradiation. It removed cationic dyes methylene blue in neutral environment and rhodamine B in acidic condition via flocculation. The removal efficiency of methylene blue and rhodamine B by flocculation was more than 95%. Moreover, it could degrade methyl orange and flocculate rhodamine B at the same time. For MO and MO-RhB solutions, the degradation rates of MO in 60 min were 85.5% and 49.1%, respectively. Furthermore, the possible pathways for the production of active species in the MO degradation reaction were discussed. This is the first HPB constructed with 4e-reduced phosphotungstate, Ba and Na ions, having the properties of photo-Fenton-like catalyst and flocculant., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The first 3D heteropoly blue Ba 2 Na 4 [SiW 4 V W 8 VI O 40 ]·19H 2 O (1) as heterogeneous Fenton-like catalyst and flocculent was hydrothermally synthesized and fully characterized by various methods 1 was an efficient Fenton-like catalyst for degradation of phenol with degradation rate of 92.1% (visible light irradiation), and 89.0% (no light) in 90min, respectively. The degradation efficiency of anionic dye methyl orange was 97.0% in 5min, when 1 was used as photo-Fenton-like catalyst under visible light. And 1 was a nice flocculent for cationic dyes methylene blue and rhodamine B, the removal rates were both above 95%. Moreover, 1 could degrade methyl orange and flocculate rhodamine B at the same time, but the degradation rate decreased from 100% to 77.5% in 60min, while the flocculation of RhB in 10min was not affected., (Copyright © 2017 Elsevier B.V. All rights reserved.)

During the exploration of highly efficient noble-metal-free electrocatalysts for the hydrogen evolution reaction (HER), a promising and challenging strategy is to fabricate composite nanocatalysts by finely tuning metal and/or nonmetal element components. Herein, we report a new HER electrocatalyst, which is composed of molybdenum phosphide and molybdenum carbide composite nanoparticles (NPs) coated by few-layer N-doped graphitic carbon shells (denoted as MoP/Mo 2 C@C). Such a new combination mode of electrocatalysts is realized by a one-step annealing route with the mixture of a Mo/P-based polyoxometalate (POM) and dicyandiamide. On the basis of this method, the simultaneous phosphorization and carbonization in a nanoscale confined space can be easily achieved by the use of POM as the molecular-element-regulating platform. MoP/Mo 2 C@C exhibits more remarkable HER performance over the whole pH range than those of MoP, Mo 2 C, and the physical mixture of MoP and Mo 2 C. The low overpotentials of 89, 136, and 75 mV were obtained at a current density of 10 mA cm -2 in the media of pH = 0, 7, and 14, respectively. Furthermore, MoP/Mo 2 C@C shows a long-term durability for 14 h over the entire pH range (0-14). Because of the protection of carbon shells, such composite electrocatalyst also possesses better transition-metal tolerance exemplified by Fe 2+ , Co 2+ , and Ni 2+ than that of 20% commercial Pt/C. This work demonstrates the advantage of POM precursors in adjusting the component and properties of nanoscale composite electrocatalysts for HER, which may suggest new options for the fabrication of highly efficient composite electrocatalysts.

Photocatalysis, a promising technology platform to address the environmental problems, has been attracting considerable attention. In this paper, Ag/Ag x H 3-x PMo 12 O 40 (simplified as Ag/AgHPMo 12 ) nanowires have been synthesized by a facile solid reaction route and in situ photodeposited method. The results of SEM and TEM indicate that the diameters of AgHPMo 12 nanowires are about 45 ± 10 nm, and Ag nanoparticles with diameters in the range of 5-15 nm are uniformly anchored on the surface of AgHPMo 12 nanowires. The Ag content in the Ag/AgHPMo 12 composite was manipulated by the light irradiation time (Ag/AgHPMo 12 -x; x stands for the irradiation time; x = 2, 4, 6, 8 h, respectively). With increasing irradiation time, the light absorption of as-synthesized samples in the visible region was gradually enhanced. The Ag/AgHPMo 12 -4 exhibits the best photocatalytic performance for the degradation of methyl orange and reduction of Cr 2 O 7 2- under visible-light (λ > 420 nm) irradiation. The study of the photocatalytic mechanism reveals that both Ag and AgHPMo 12 can be excited by visible light. The photoinduced electrons were transferred from AgHPMo 12 to metallic Ag, and combined with the Ag plasmonic holes. The Ag plasmonic electrons were trapped by O 2 to form ·O 2 - , or directly reduced Cr 2 O 7 2- to Cr 3+ . Meanwhile, the ·O 2 - species and the photogenerated holes of AgHPMo 12 were used to oxidize MO or i-PrOH; thus, they showed highly efficient and recyclable photocatalytic performance for removing the organic and inorganic pollutants.

The loading of noble-metal nanoparticles (NMNPs) onto various carriers to obtain stable and highly efficient catalysts is currently an important strategy in the development of noble metal (NM)-based catalytic reactions and their applications. We herein report a nanowire supramolecular assembly constructed from the surfactant-encapsulating polyoxometalates (SEPs) CTAB-PW 12 , which can act as new carriers for NMNPs. In this case, the Ag NPs are loaded onto the SEP nanowire assembly with a narrow size distribution from 5 to 20 nm in diameter; the average size is approximately 10 nm. The Ag NPs on the nanowire assemblies are well stabilized and the over agglomeration of Ag NPs is avoided owing to the existence of well-arranged polyoxometalate (POM) units in the SEP assembly and the hydrophobic surfactant on the surface of the nanowire assembly. Furthermore, the loading amount of the Ag NPs can be adjusted by controlling the concentration of the AgNO 3 aqueous solution. The resultant Ag/CTAB-PW 12 composite materials exhibit high activity and good stability for the catalytic reduction of 4-nitrophenol (4-NP) with NaBH 4 in isopropanol/H 2 O solution. The NMNPs-loaded SEP nanoassembly may represent a new composite catalyst system for application in NM-based catalysis., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Rational design of earth-abundant photocatalysts is an important issue for solar energy conversion and storage. Polyoxometalate (POM)@Co 3 O 4 composites doped with highly dispersive molecular metal-oxo clusters, synthesized by loading a single Keggin-type POM cluster into each confined space of a metal-organic framework (MOF), exhibit significantly improved photocatalytic activity in water oxidation compared to the pure MOF-derived nanostructure. The systematic synthesis of these composite nanocrystals allows the conditions to be tuned, and their respective water oxidation catalytic performance can be efficiently adjusted by varying the thermal treatment temperature and the feeding amount of the POM. This work not only provides a modular and tunable synthetic strategy for preparing molecular cluster@TM oxide (TM=transition metal) nanostructures, but also showcases a universal strategy that is applicable to design and construct multifunctional nanoporous metal oxide composite materials., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We report the crystallization of homochiral polyoxometalate (POM) macroanions {CoSb 6 O 4 (H 2 O) 3 [Co(hmta)SbW 8 O 31 ] 3 } 15- ( 1 , hmta = hexamethylenetetramine) via the counter cation-mediated chiral symmetry breaking and asymmetric autocatalytic processes. In the presence of low Co 2+ concentrations both Δ- and Λ-enantiomers of 1 formed in the reaction, crystallizing into the racemic crystal rac - 1 . At a high Co 2+ concentration, the polyoxoanion enantiomers showed a high level of chiral recognition via H-bonding interactions to crystallize into enantiopure crystals of Δ- or Λ-[Co(H 2 O) 6 {CoSb 6 O 4 (H 2 O) 3 [Co(hmta)SbW 8 O 31 ] 3 }] 13- . During crystallization, a microscale symmetry-breaking event and a nonlinear asymmetric autocatalysis process make the enantiomers crystallize in different batches, which provides an opportunity to isolate the homochiral bulk materials. The defined structures of the racemic and homochiral crystals thus provide a molecular-level illustration that H-bonding interactions are responsible for such high-level chiral recognition, in a process similar to the supramolecular chirality frequently observed in biology. These POM macroanions showed a high cytotoxicity against various cancer cells, particularly ovarian cancer cells. The antitumor activity of these compounds resulted at least in part from the activation of the apoptotic pathways, as shown by the flow cytometry, Annexin V staining, DNA ladder, and TUNEL assay, likely by blocking the cell cycle and complexing with proteins in cells. The POM macroanions reported herein provide promising and novel antitumor agents for the potential treatment of various cancers.

Mimicking proton conduction mechanism of Nafion to construct novel proton-conducting materials with low cost and high proton conductivity is of wide interest. Herein, we have designed and synthesized a cationic covalent organic framework with high thermal and chemical stability by combining a cationic monomer, ethidium bromide (EB) (3,8-diamino-5-ethyl-6-phenylphenanthridinium bromide), with 1,3,5-triformylphloroglucinol (TFP) in Schiff base reactions. This is the first time that the stable cationic crystalline frameworks allowed for the fabrication of a series of charged COFs (EB-COF:X, X = F, Cl, Br, I) through ion exchange processes. Exchange of the extra framework ions can finely modulate the COFs' porosity and pore sizes at nanoscale. More importantly, by introducing PW12O40(3-) into this porous cationic framework, we can greatly enhance the proton conductivity of ionic COF-based material. To the best of our knowledge, EB-COF:PW12 shows the best proton conductivity at room temperature among ever reported porous organic materials.

Three hybrid coordination networks that were constructed from ɛ-Keggin polyoxometalate building units and imidazole-based bridging ligands were prepared under hydrothermal conditions, that is, H[(Hbimb)2 (bimb){Zn4 PMo(V8) Mo(VI) 4O40}]⋅6 H2O(1), [Zn(Hbimbp)(bimbp)3 {Zn4 PMo(V8) Mo(VI) 4O40}]⋅DMF⋅3.5 H2O(2), and H[Zn2 (timb)2 (bimba)2 Cl2 {Zn4 PMo(V8) Mo(VI) 4O40}]⋅7 H2O(3) (bimb=1,4-bis(1-imidazolyl)benzene, bimbp=4,4'-bis(imidazolyl)biphenyl, timb=1,3,5-tris(1-imidazolyl)benzene, bimba=3,5-bis(1-imidazolyl)benzenamine). All three compounds were characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and single-crystal X-ray diffraction. The mixed valence of the Mo centers was analyzed by XPS spectroscopy and bond-valence sum calculations. In all three compounds, the ɛ-Keggin polyoxometalate (POM) units acted as nodes that were connected by rigid imidazole-based bridging ligands to form hybrid coordination networks. In compound 1, 1D zigzag chains extended to form a 3D supramolecular architecture through intermolecular hydrogen-bonding interactions. Compound 2 consisted of 2D curved sheets, whilst compound 3 contained chiral 2D networks. Because of the intrinsic reducing properties of ɛ-Keggin POM species, noble-metal nanoparticles were loaded onto these POM-based coordination networks. Thus, compounds 1-3 were successfully loaded with Ag nanoparticles, and the corresponding composite materials exhibited high catalytic activities for the reduction of 4-nitrophenol., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A di-vanadium-substituted Lindqvist-type polyoxometalate [Cu(C12H8N2)2]2[V2W4O19]·4H2O (1) was hydrothermally synthesized and characterized structurally by single crystal X-ray diffraction analysis. X-ray photoelectron spectroscopy and energy disperse spectroscopy tests further prove the existence of vanadium. Ultraviolet photoelectron spectroscopy and density functional theoretical studies indicate that the energy level of 1 matches well with the conduction band of the TiO2. Furthermore, considering the semiconductor-like nature of 1 and the introduction of transition metal element Cu synchronously extends the absorption to the visible region, which should also be beneficial to the photovoltaic device performance. 1-Doped TiO2 composites (denoted as 1@TiO2) have been successfully fabricated by a simple sol-gel method, and introduced into the dye-sensitized solar cells (DSSCs) as co-sensitizers in N719-sensitized photoanodes by mixing 1@TiO2 with P25 nanoparticles with different weight ratios to enhance the photoelectric conversion efficiency. The investigations show that the DSSC assembled with 1@TiO2/19P25 photoanode has the best performance and the overall improvement of the efficiency is 21.6% compared with pure P25. Furthermore, the electrochemical impedance spectroscopy and open-circuit voltage decay investigations show that the cosensitization of 1 and N719 can promote electron transfer and restrain charge recombinations in the DSSCs, resulting in a longer electron lifetime.

The reaction of Keggin-type polyoxometalate (POM) units, transition-metal (TM) ions, and a rigid bis(imidazole) ligand (1,4-bis(1-imidazolyl)benzene (bimb)) in a hydrothermal environment led to the isolation of four new POM-based metal-organic networks, [H2 L][CuL][SiW12 O40 ]⋅2 H2 O (1), [H2 L]2 [Co(H2 O)3 L][SiW11 CoO39 ]⋅6 H2 O (2), KH[CuL]2 [SiW11 CoO39 (H2 O)]⋅2 H2 O (3), and [CuL]4 [GeW12 O40 ]⋅H2 O (4; L=bimb). All four compounds were characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. Compounds 1 and 3 are new 3D networks with 1D channels. Compounds 2 and 4 contain 2D networks, which further stack into 3D supramolecular networks. The contributions of pH value, the negative charge of the POM, and the TM coordination modes to the construction of 3D networks were elucidated by comparing the synthetic conditions and structures of compounds 1-4. The photocatalytic properties of compounds 1-4 were investigated using methylene blue (MB) degradation under UV light. All compounds showed good catalytic activity and structural stability. The possible catalytic mechanism was discussed on the basis of active-species trapping experiments. The different photocatalytic activities of compounds 1-4 were explained by comparison of the band gaps of different POM species and different packing modes of POM units in these hybrid compounds., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A series of polynuclear metal-oxo clusters have been constructed from the dynamic polyoxometalate (POM) building block {B-α-Sb(III)W9O33} and lanthanide (Ln) linkers via a stepwise synthetic strategy with the molecular formulas of [Ln2(H2O)4{WO2(pic)}2(SbW8O30)2](10-) (Na4Li6[La-1]·28H2O, Na3Li7[Pr-2]·30H2O) and [{Ln(H2O)}{Ln(pic)}(Sb3O4)(SbW8O31)(SbW10O35)]2(24-) (K2Na6Li16[Tb-3]·63H2O, Na9Li15[Dy-4]·61H2O, Na7Li17[Ho-5]·53H2O) (Hpic = picolinic acid). The five compounds have been characterized by FT-IR, elemental analysis, TG, powder X-ray diffraction (PXRD) and single crystal X-ray diffraction. In compounds 1-5, various POM moieties, such as {B-β-SbW8O30}, {B-α-SbW8O31} and {B-α-SbW10O35}, were formed through a series of disassembling and re-assembling processes of the dynamic {B-α-SbW9O33} precursor with specific pH, reaction temperature and time. Furthermore, the use of oxytropic Ln(3+) ions as linkers, together with auxiliary organic pic ligands and/or inorganic Sb(3+) ions, led to diverse connection modes between the POM building blocks and Ln linkers and the assembly of new polynuclear metal-oxo clusters. The polyoxoanions of La-1 and Pr-2 possess the same structural feature, which can be viewed as a sandwich-type cluster composed of two {B-β-SbW8O30} units connected by two {WO2(pic)} fragments and two hydrated Ln ions. These sandwich-type polyoxoanions are further linked by the hydrated Ln ions to form a 1-D helical chain. The polyoxoanions of Tb-3, Dy-4 and Ho-5 display the same structural features, although they contain different counter-cations and lattice water molecules. In the polyoxoanions of 3-5, one {B-α-SbW8O31} POM moiety and one {B-α-SbW10O35} POM unit are connected by one {Sb3O4} fragment and one {Ln(pic)} linker, forming an asymmetric sandwich-type metal-oxo cluster. Two of these sandwich-type clusters are further fused together by extra two hydrated Ln ions, leading to an isolated polynuclear metal-oxo cluster with a size of 16.4 × 28.5 Å. The photoluminescence properties of Tb-3 and Dy-4 were investigated. Both compounds exhibit characteristic Tb(3+) and Dy(3+) luminescence. The relationship between the luminescence properties and the crystal structure of the polyoxoanion was discussed.

A large lanthanide-containing tungstotellurites(iv) nanocluster Na18[Ce10Te8W88O298(OH)12(H2O)40]·54H2O () was synthesized by combining cerium linkers and TeO3(2-) heteroanion templates. The macroanion in consists of two identical [Te4W42O144(OH)6Ce4(H2O)13](14-) subunits and two triangle-shaped {W2O5Ce(H2O)7} linkers.

A versatile one-pot strategy was used to synthesize two large, purely inorganic selenotungstates, nanocluster K(6)Na(16) [Ce(6)Se(6)W(67)O(230) (OH)(6) (H(2)O)(17)]⋅47 H(2)O (1) and layer K(9)Na(5) Ce(H(2)O)(4) [Ce(6)Se(10)W(51)O(187) (OH)(7) (H(2)O)(18)]⋅45H(2)O(2), by combining cerium centers and SeO(3) (2-) heteroanion templates. Compound 1 displays a Ce-stabilized hexameric nanocluster with one rhombus-like {W(4)O(15) (OH)(3)} unit in the center, whereas compound 2 is the first example of a Ce-bridged layer selenotungstate network based on linkage of the unusual {Ce(6)Se(10)W(51)O(187) (OH)(7) (H(2)O)(18)} clusters and additional Ce(H(2)O)(4) fragments via Ce-O-Se bridges. The compounds were characterized by elemental analyses, IR spectroscopy, thermogravimetric analyses, powder and single-crystal X-ray diffraction, and electrospray ionization mass spectrometry. Moreover, the electrochemical property of compound 1 was also investigated., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Three new polyoxometalate(POM)-based polynuclear nickel clusters, Na24[Ni12(OH)9(CO3)3(PO4)(SiW9O34)3]·56H2O (1), Na25[Ni13(H2O)3(OH)9(PO4)4(SiW9O34)3]·50H2O (2), and Na50[Ni25(H2O)2OH)18(CO3)2(PO4)6(SiW9O34)6]·85H2O (3) were synthesized and structurally characterized. Compounds 1-3 contain {Ni12}, {Ni13} and {Ni25} core, respectively, connected by the inorganic {OH}, {PO4} and/or {CO3} linkers and encapsulated by the lacunary A-α-{SiW9O34} POM units. Compound 3 represents the currently largest POM-based Ni clusters. All three compounds contain {Ni3O3} quasi-cubane or {Ni4O4} cubane units, which are similar to the natural oxygen-evolving center {Mn4O5Ca} in photosystem II (PSII). Visible light-driven water oxidation experiments with compounds 1-3 as the homogeneous catalysts indicate that all three compounds show good photocatalytic activities. The O2 evolution amount corresponds to a high TON of 128.2 for 1, 147.6 for 2, and 204.5 for 3, respectively. Multiple experiments including dynamic light-scattering, UV-vis absorption, catalysts aged experiments, tetra-n-heptylammonium nitrate (THpANO3) toluene extraction, and capillary electrophoretic measurements results confirm that compounds 1-3 are dominant active catalysts but not Ni(2+) ions(aq) or nickel oxide under the photocatalytic conditions. The above research results indicate a new and all-inorganic polynuclear Ni-based structural model as the visible light-driven water oxidation catalysts.

The research on chiral recognition and chiral selection is not only fundamental in resolving the puzzle of homochirality, but also instructive in chiral separation and stereoselective catalysis. Here we report the chiral recognition and chiral selection during the self-assembly process of two enantiomeric wheel-shaped macroanions, [Fe28(μ3-O)8(Tart)16(HCOO)24](20-) (Tart=D- or L-tartaric acid tetra-anion). The enantiomers are observed to remain self-sorted and self-assemble into their individual assemblies in their racemic mixture solution. The addition of chiral co-anions can selectively suppress the self-assembly process of the enantiomeric macroanions, which is further used to separate the two enantiomers from their mixtures on the basis of the size difference between the monomers and the assemblies. We believe that delicate long-range electrostatic interactions could be responsible for such high-level chiral recognition and selection.

A new cationic triazole-based metal-organic framework encapsulating Keggin-type polyoxometalates, with the molecular formula [Co(BBPTZ)3][HPMo12O40]⋅24 H2O [compound 1; BBPTZ = 4,4'-bis(1,2,4-triazol-1-ylmethyl)biphenyl] is hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. The structure of compound 1 contains a non-interpenetrated 3D CdSO4 (cds)-type framework with two types of channels that are interconnected with each other; straight channels that are occupied by the Keggin-type POM anions, and wavelike channels that contain lattice water molecules. The catalytic activity of compound 1 in the oxidative desulfurization reaction indicates that it is not only an effective and size-selective heterogeneous catalyst, but it also exhibits distinct structural stability in the catalytic reaction system., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Two unprecedented tetrameric selenotungstates based on different Wells-Dawson-type fragments have been obtained: the {Sn7Se8W54} nanocluster exhibiting photocatalytic H2 evolution activity and the {Sn16Se11W56} chain, which are the first dimethyltin-functionalized selenotungstates reported and contain the unique {β-Se2W15} and {γ-Se2W14} building blocks, respectively.

Two novel open-chain carboxyethyltin decorated sandwich-type germanotungstates have been successfully synthesized. They could markedly increase the electrocatalytic activity of single-walled carbon nanotubes toward triiodide reduction when assembled into composite electrodes, which have shown a conversion efficiency of 6.32% that is comparable to that of Pt electrodes (6.29%) when used as counter electrodes in dye-sensitized solar cells.

The introduction of an extended bridging bis(triazole) ligand, that is, 4,4'-bis(1,2,4-triazol-1-ylmethyl)biphenyl (BBPTZ), into the hydrothermal reaction system containing transition metal ions and Keggin-type polyoxometalates (POMs) led to the isolation of three new organic-inorganic hybrid entangled coordination networks, [Cu(I)2Cu(II)(BBPTZ)6][SiW12O40]⋅12H2O (1), [Ni(BBPTZ)2(H2O)][H2SiW12O40]⋅11H2O (2), and [Ni2(BBPTZ)4(H2O)2][SiW12O40]⋅3H2O (3). All three compounds were characterized by elemental analysis, IR spectroscopy, TG analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. Compound 1 contains a 2-D POM-based metal-organic layer entangled with 1-D ladder-like metal-organic chains. The adjacent 2-D networks are parallel to each other, further stacking into a 3-D supramolecular framework with 1-D channels. Compound 2 exhibits a 1-D cantilever-type loop-containing chain. The Keggin-type POMs act as the cantilever groups, leading to the adjacent catilever-type chains interwaving together to form a 3-D supramolecular open framework with two types of channels. Compound 3 possesses a 3-D open framework based on 2-D metal-organic undulated layer and Keggin-type POM clusters. Three sets of such frameworks further interpenetrate with each other to form an interesting three-fold interpenetrating framework. The photocatalytic activities of compounds 1-3 for the decomposition of methylene blue (MB) under UV light have been investigated., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A vanadtungstate cluster-based organic-inorganic hybrid material [NiL4V(IV)W(VI)10W(V)2O40(V(IV)O)2] (1, L = 1,4-bis(imidazol-1-ylmethyl)benzene) was synthesized and characterized by elemental analysis, IR spectra, thermal gravimetric analysis, and single crystal X-ray diffraction analysis. Structural analysis reveals that compound 1 contains a transition metal-centered, bicapped Keggin-type {VW12O40(VO)2} core, connected by nickel linkers into a 1-D chain. These 1D chains interdigitated with each other, achieving an interdigitated 3D supermolecular architecture. Photocatalytic studies indicate that compound 1 exhibits not only active photocatalytic degradation of dye molecules, but also selective photocatalytic activity for degradation of cationic dyes in aqueous solution. Further, this photocatalyst is stable and easily separated from the photocatalytic system for reuse as well.

Two Fe-substituted Dawson-type nanoscale selenotungstate clusters, {Fe6Se6W34} and {Fe10Se8W62} involving {α-Se2W14} and {γ-Se2W14} building blocks, have been isolated, which exhibit photocatalytic H2 evolution activity. Their electrochemical behaviours and magnetic properties were also investigated.

A new 3D extended heteropoly blue Ba4[SiW(V)4W(VI)8O40]·H2O (1) composed of twelve-coordinated α-Keggin anions [SiW(V)4W(VI)8O40](8-) and eight-coordinated Ba sites {BaO8} has been hydrothermally synthesized and fully characterized by elemental analysis, IR spectroscopy, XPS, single crystal X-ray and X-ray powder (XRPD) diffraction. 1 represents the first inorganic 3D framework constructed from four-electron reduced α-Keggin anions linked by alkaline earth metals. The photocatalytic activity of 1 has been evaluated for rhodamine B (RhB) degradation. 1 exhibits excellent catalytic activity for the degradation of RhB in the presence of H2O2and the involvement of visible light makes a more complete degradation. The results of the current study suggest that multi-electron reduced polyoxometalates can catalyze efficient degradation of an organic dye with H2O2.

Two phosphoniobate-based 3D frameworks were firstly constructed using the hexa-capped Keggin polyoxoniobates [PNb12O40(VO)6](3-) and copper cations. Photocatalytic studies indicated that the hybrid materials exhibit photocatalytic hydrogen evolution activity.

Various polyoxometalates (POMs) were successfully immobilized to the mesoporous coordination polymer MIL-101 resulting in a series of POM-MOF composite materials POM@MIL-101 (POM = K4PW11VO40, H3PW12O40, K4SiW12O40). These materials were synthesized by a simple one-pot reaction of Keggin POMs, tetramethylammonium hydroxide (TMAH), terephthalic acid (H2bdc), and Cr(3+) ions. XRD, FTIR, thermogravimetric analyses (TG), inductively coupled plasma (ICP) spectrometry, and energy-dispersive X-ray spectroscopy (EDX) collectively confirmed the successful combination of POMs and the porous framework. Further, these composites POM@MIL-101 with different loading of POMs were achieved by variation of the POM dosage. Notably, the uptake capacity of MIL-101 towards organic pollutants in aqueous solution was significantly improved by immobilization of hydrophilic POMs into cages of MIL-101. An uptake capacity of 371 mg g(-1), comparable to that of the graphene oxide sponges, and much higher than that of the commercial activated carbon, was achieved at room temperature in 5 min when dipping 20 mg PW11V@MIL-101 in the methylene blue (MB) solution (100 mL of 100 mg L(-1) MB solution). Further study revealed that the POM@MIL-101 composite materials not only exhibited a fast adsorption rate towards dye molecules, but also possessed of selective adsorption ability of the cationic dyes in wastewater. For example, the adsorption efficiency of PW11V@MIL-101 (10 mg) towards MB (100 mL of 10 mg L(-1)) could reach 98 % in the initial 5 min, and it could capture MB dye molecules from the binary mixture of the MB and MO with similar size. Also, the POM@MIL-101 materials could be readily recycled and reused, and no POM leached in the dye adsorption process., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Aim: To investigate the feasibility of lectin microarray for differentiating gastric cancer from gastric ulcer., Methods: Twenty cases of human gastric cancer tissue and 20 cases of human gastric ulcer tissue were collected and processed. Protein was extracted from the frozen tissues and stored. The lectins were dissolved in buffer, and the sugar-binding specificities of lectins and the layout of the lectin microarray were summarized. The median of the effective data points for each lectin was globally normalized to the sum of medians of all effective data points for each lectin in one block. Formalin-fixed paraffin-embedded gastric cancer tissues and their corresponding gastric ulcer tissues were subjected to Ag retrieval. Biotinylated lectin was used as the primary antibody and HRP-streptavidin as the secondary antibody. The glycopatterns of glycoprotein in gastric cancer and gastric ulcer specimens were determined by lectin microarray, and then validated by lectin histochemistry. Data are presented as mean ± SD for the indicated number of independent experiments., Results: The glycosylation level of gastric cancer was significantly higher than that in ulcer. In gastric cancer, most of the lectin binders showed positive signals and the intensity of the signals was stronger, whereas the opposite was the case for ulcers. Significant differences in the pathological score of the two lectins were apparent between ulcer and gastric cancer tissues using the same lectin. For MPL and VVA, all types of gastric cancer detected showed stronger staining and a higher positive rate in comparison with ulcer, especially in the case of signet ring cell carcinoma and intra-mucosal carcinoma. GalNAc bound to MPL showed a significant increase. A statistically significant association between MPL and gastric cancer was observed. As with MPL, there were significant differences in VVA staining between gastric cancer and ulcer., Conclusion: Lectin microarray can differentiate the different glycopatterns in gastric cancer and gastric ulcer, and the lectins MPL and VVA can be used as biomarkers.

A series of all-inorganic, abundant-metal-based, high-nuclearity cobalt-phosphate (Co-Pi) molecular catalysts [{Co4(OH)3(PO4)}4(SiW9O34)4](32-) (1), [{Co4(OH)3(PO4)}4(GeW9O34)4](32-) (2), [{Co4(OH)3(PO4)}4(PW9O34)4](28-) (3), and [{Co4(OH)3(PO4)}4(AsW9O34)4](28-) (4) were synthesized and shown to be highly effective at photocatalytic water oxidation. The {Co16(PO4)4} cluster contains a Co4O4 cubane which is structurally analogous to the [Mn3CaO4] core of the oxygen-evolving complex (OEC) in photosystem II (PSII). Compounds 1-4 were shown to be the first POM-based Co-Pi-cluster molecular catalysts for visible light-driven water oxidation, thus serving as a functional model of the OEC in PSII. The systematic synthesis of four isostructural analogues allowed for investigating the influence of different heteroatoms in the POM ligands on the photocatalytic activities of these Co-Pi cluster WOCs. Further, the POM-based photocatalysts readily recrystallized from the photocatalytic reaction systems with the polyoxoanion structures unchanged, which together with the laser flash photolysis, dynamic light-scattering, (31)P NMR, UV-vis absorption, POM extraction, and ICP-MS analysis results collectively confirmed that compounds 1-4 maintain their structural integrity under the photocatalytic conditions. This study provides not only a valuable molecular model of the "Co-Pi" catalysts with a well-defined structure but also an unprecedented opportunity to fine-tune high-nuclearity POM clusters for visible light-driven water splitting.

Reactions of hexaniobate with vanadate in the presence of Ni(2+) , Zn(2+) , or Cu(2+) have furnished three high-nuclear vanadium cluster-substituted heteropolyoxoniobates (HPNs): {Ni(en)3 }5 H{V(V) Nb8 V(IV) 8 O44 }⋅9 H2 O (1), (H2 en)Na2 [{Zn(en)2 (Hen)}{Zn(en)2 (H2 O)}2 {PNb8 V(IV) 8 O44 }]⋅11 H2 O (2), and Na{Cu(en)2 }3 {[Cu(en)2 ]2 [PNb8 V(IV) 8 O44 ]}⋅11 H2 O (3) (en=1,2-diaminoethane). Their structures have been determined and characterized by single-crystal X-ray diffraction analysis, thermogravimetric analysis (TGA), and elemental analysis. Structural analysis has revealed that compounds 1-3 contain similar {V8 }-substituted [X(V) Nb8 V(IV) 8 O44 ](11-) (X=P, V) clusters, obtained by inserting a {V8 } ring into tetravacant HPN [XNb8 O36 ](27-) . To the best of our knowledge, compounds 1-3 represent the first high-nuclear vanadium cluster-substituted HPNs, and compound 1 is the largest vanadoniobate cluster yet obtained in HPN chemistry. Nickel and zinc cations have been introduced into HPNs for the first time, which might promise a more diverse set of structures in this family. Antitumor studies have indicated that compounds 1 and 2 exhibit high activity against human gastric cancer SGC-7901 cells, SC-1680 cells, and MG-63 cells., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Investigation into a hydrothermal reaction system with transition-metal (TM) ions, 1,4-bis(1,2,4-triazol-1-lmethyl)benzene (BBTZ) and various charge-tunable Keggin-type polyoxometalates (POMs) led to the preparation of four new entangled coordination networks, [Co(II) (HBBTZ)(BBTZ)2.5 ][PMo12 O40 ] (1), [Cu(I) (BBTZ)]5 [BW12 O40 ]⋅H2 O (2), [Cu(II) (BBTZ)]3 [AsW(V) 3 W(VI) 9 O40 ]⋅10 H2 O (3), and [Cu(II) 5 (BBTZ)7 (H2 O)6 ][P2 W22 Cu2 O77 (OH)2 ]⋅6 H2 O (4). All compounds were characterized by using elemental analysis, IR spectroscopy, thermogravimetric analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. The mixed valence of W centers in compound 3 was further confirmed by using XPS spectroscopy and bond-valence sum calculations. In the structural analysis, the entangled networks of 1-4 demonstrate zipper-closing packing, 3D polythreading, 3D polycatenation, and 3D self-penetration, respectively. Moreover, with the enhancement of POM negative charges and the use of different TM types, the number of nodes in the coordination networks of 1-4 increased and the basic metal-organic building motifs changed from a 1D zipper-type chain (in 1) to a 2D pseudorotaxane layer (in 2) to a 3D diamond-like framework (in 3) and finally to a 3D self-penetrating framework (in 4). The photocatalytic properties of compounds 1-4 for the degradation of methylene blue under UV light were also investigated; all compounds showed good catalytic activity and the photocatalytic activity order of Keggin-type species was initially found to be {XMo12 O40 }>{XW12 O40 }>{XW12-n TMn O40 }., (Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Three trimeric polyoxovanadate based on 1:13 anions [MnV13O38](7-) with lanthanide cations Ln(3+) (Ln = La, Ce and Nd) and pyridine-3-carboxylic acid: HK3{[Ln(H2O)4]6[MnV13O38]3(SO4)2}·3(C6H6NO2)·nH2O (Ln = La 1, Nd 3; n = 33 for 1, 20 for 3), H(2.5)K(1.5){[Ce(H2O)4]6[MnV13O38]3(SO4)2}·3(C6H6NO2)·20.5H2O (2) (C6H5NO2 = pyridine-3-carboxylic acid) have been synthesized and characterized by elemental analysis, IR spectroscopy, UV spectroscopy, TG analysis, XPRD, electrochemical analyses, magnetism and single-crystal X-ray diffraction. Compounds 1-3 are isostructural and crystallized in the hexagonal system, space group P6(3)/m. Compounds 1-3 contain an unusual trimeric polyoxoanion [{Ln2MnV13O38}3(SO4)2](7-), representing the first polyoxovanadate-based trimeric aggregate with rare earth ions. The electrochemical and electrocatalytic properties of the compounds have been investigated. Magnetic studies indicate that antiferromagnetic interactions exist in the compounds.

The spin-crossover complex [Fe(LN5)(CN)2]·H2O (1, LN5 = 2,13-dimethyl-3,6,9-12,18-pentaazabicyclo[12.3.1]octadeca-1(18),2,12,14,16-pentaene), reported previously by Nelson et al. in 1986, was reinvestigated, and its structure determined by single crystal X-ray diffraction for the first time. The reaction between [Mn(III)(saltmen)(H2O)](+) and this photomagnetic linker yielded the trinuclear molecular complex [{Mn(saltmen)}2FeHS(LN5)(CN)2](ClO4)2·0.5CH3OH (2) and the one-dimensional compound [{Mn(saltmen)}2FeLS(LN5)(CN)2](ClO4)2·0.5C4H10O·0.5H2O (3) depending on the addition order of the reagents (HS: High-Spin; LS: Low-Spin). Compound 3 exhibits a wave-shaped chain structure built from the assembly of the trinuclear [Mn(III)-NC-Fe(II)] motif found in 2. Static magnetic measurements revealed the existence of antiferromagnetic Mn(III)···Fe(II) (Fe(II) HS, S = 2) interactions in the trinuclear entity of 2 via the cyanido bridge leading to an ST = 2 ground state. In the case of 3, concomitant ferromagnetic and antiferromagnetic exchange interactions are found along the chain due to the presence of two crystallographically independent {Mn2(saltmen)2} units, which behave differently as shown by the magnetic susceptibility analysis, while the Fe(II) (LS, S = 0) cyanido-bridging moiety is isolating these dinuclear Mn(III) units. ac susceptibility experiments indicated slow relaxation of the magnetization arising from the ferromagnetically coupled [Mn2] units (τ0 = 1.1 × 10(-7) s and Δ(eff)/k(B) = 13.9 K). Optical reflectivity and photomagnetic properties of 1 and 3 have been investigated in detail. These studies reveal that the photomagnetic properties of 1 are kept after its coordination to the acceptor Mn(III)/saltmen complexes, allowing in 3 to switch "on" and "off" the magnetic interaction between the photoinduced Fe(II) HS unit (S = 2) and the Mn(III) ions. To the best of our knowledge, the compound 3 represents the first example of a coordination network of single-molecule magnets linked by spin-crossover units inducing thermally and photoreversible magnetic and optical properties.

Two novel copper-2,2'-bipyridine complexes [Cu(SAL)(2,2'-bipy)ClO4]2 (1) and [Cu(μ2-O)(2,2'-bipy)NO3]2 (2) (HSAL=salicylaldehyde) were synthesized and characterized by X-ray single-crystal diffraction, elemental analysis and IR spectra. The interactions of the complexes with salmon sperm DNA were investigated by viscosity analysis, UV, fluorescence and circular dichroism (CD) spectroscopic techniques. Absorption spectral (Kb=3.00×10(5)M(-1) (1), 3.49×10(5)M(-1)(2)), emission spectral ((Ksv) 3.33×10(4)M(-1) (1), 3.40×10(4)M(-1) (2)), and viscosity measurements reveal that 1 and 2 interact with DNA through intercalation. In fluorimetric studies, the enthalpy (ΔH>0) and entropy (ΔS>0) changes of the reactions between the Cu (II) complexes with DNA demonstrate hydrophobic interactions. In addition, CD study indicates the Cu (II) complexes cause a more B-like to a more A-like conformational change upon binding DNA. All the experimental results show that the interaction mode of the two complexes was greatly affected by the coordination environments of Cu (II) centers. Their in vitro cytotoxicity towards five selected tumor cell lines HepG-2, HeLa, NCI-H460, MCF-7 and HL-60 has been evaluated by MTT method, and 2 exhibits higher growth inhibition of the selected cell lines at concentration of 50 μM, this result is identical with their DNA binding ability order., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Purely inorganic porous frameworks using catalytically active [MnV13O38](7-) clusters as nodes and rare earth ions as linkers have been successfully prepared. The POM-based porous framework is a kind of multifunctional material, which exhibits selective adsorption behavior and remarkable catalytic activity for the heterogeneous oxidation of sulfides.

A polyoxometalate (POM)-based {Mn(IV)2Mn(III)6Mn(II)4} complex with single-molecule magnet (SMM) behaviour was prepared, exhibiting the largest known Mn nuclearity and the most Mn valence states in the POM-based SMM family.