Vanadium-based nanomaterials for cancer diagnosis and treatment.

In the past few decades, various vanadium compounds have displayed potential in cancer treatment. However, fast clearness in the body and possible toxicity of vanadium compounds has hindered their further development. Vanadium-based nanomaterials not only overcome these limitations, but take advantage of the internal properties of vanadium in photics and magnetics, which enable them as a multimodal platform for cancer diagnosis and treatment. In this paper, we first introduced the basic biological and pharmacological functions of vanadium compounds in treating cancer. Then, the synthesis routes of three vanadium-based nanomaterials were discussed, including vanadium oxides, 2D vanadium sulfides, carbides and nitrides: VmXn (X = S, C, N) and water-insoluble vanadium salts. Finally, we highlighted the applications of these vanadium-based nanomaterials as tumor therapeutic and diagnostic agents.

Synthesis, Crystal Structure, and Computational Methods of Vanadium and Copper Compounds as Potential Drugs for Cancer Treatment.

Transition metal-based compounds have shown promising uses as therapeutic agents. Among their unique characteristics, these compounds are suitable for interaction with specific biological targets, making them important potential drugs to treat various diseases. Copper compounds, of which Casiopeinas® are an excellent example, have shown promising results as alternatives to current cancer therapies, in part because of their intercalative properties with DNA. Vanadium compounds have been extensively studied for their pharmacological properties and application, mostly in diabetes, although recently, there is a growing interest in testing their activity as anti-cancer agents. In the present work, two compounds, [Cu(Metf)(bipy)Cl]Cl·2H2O and [Cu(Impy)(Gly)(H2O)]VO3, were obtained and characterized by visible and FTIR spectroscopies, single-crystal X-ray diffraction, and theoretical methods. The structural and electronic properties of the compounds were calculated through the density functional theory (DFT) using the Austin-Frisch-Petersson functional with dispersion APFD, and the 6-311 + G(2d,p) basis set. Non-covalent interactions were analyzed using Hirshfeld surface analysis (HSA) and atom in molecules analysis (AIM). Additionally, docking analysis to test DNA/RNA interactions with the Casiopeina-like complexes were carried out. The compounds provide metals that can interact with critical biological targets. In addition, they show interesting non-covalent interactions that are responsible for their supramolecular arrangements.

Recognition of V3+/V4+/V5+ Multielectron Reactions in Na3V(PO4)2: A Potential High Energy Density Cathode for Sodium-Ion Batteries.

Na3V(PO4)2 was reported recently as a novel cathode material with high theoretical energy density for Sodium-ion batteries (SIBs). However, whether V3+/V4+/V5+ multielectron reactions can be realized during the charging process is still an open question. In this work, Na3V(PO4)2 is synthesized by using a solid-state method. Its atomic composition and crystal structure are verified by X-ray diffraction (XRD) and neutron diffraction (ND) joint refinement. The electrochemical performance of Na3V(PO4)2 is evaluated in two different voltage windows, namely 2.5-3.8 and 2.5-4.3 V. 51V solid-state NMR (ssNMR) results disclose the presence of V5+ in Na2-xV(PO4)2 when charging Na3V(PO4)2 to 4.3 V, confirming Na3V(PO4)2 is a potential high energy density cathode through realization of V3+/V4+/V5+ multielectron reactions.

V2O5 Nanobelts Mimick Tandem Enzymes To Achieve Nonenzymatic Online Monitoring of Glucose in Living Rat Brain.

The continuous detection of glucose is significant for revealing its role in neuron protection and for diagnosis of various diseases. In this study, for the first time, a nonenzymatic online optical detection platform (OODP) for glucose measurement in rat brain utilizing the tandem enzyme activity of V2O5 nanobelts is developed. V2O5 nanobelts were synthesized via a facile solvothermal strategy, and for the first time it is found that the V2O5 nanobelts possess dual enzyme-like activity, i.e., glucose oxidase (GOx)-like and peroxidase-like activity, and can act as a "tandem nanozyme". To investigate the mechanisms of the GOx-like property, we built an adsorption model, and the RPBE density functional calculations indicate that the glucose molecule can be adsorbed on the V2O5 plane. Based on the ability of V2O5 nanobelts to mimick tandem enzymes, a nonenzymatic online optical detection platform (OODP) for the continuous monitoring of glucose in rat brain was designed, which exhibits excellent stability, high selectivity, and a wide linear detection range from 0.2 to 5 mM and records cerebral glucose alterations in the calm/ischemia model. This facile but reliable nonenzymatic online optical glucose measurement compares favorably with natural enzyme-based online electrochemical glucose analytical systems, and its ready adoption by physiologists and pathologists will facilitate the understanding of brain function and the pathogenesis of diabetes.

Vanadium(V) tris-3,5-di-tert-butylcatecholato complex: Links between speciation and anti-proliferative activity in human pancreatic cancer cells.

Vanadium complexes are intensively tested for anti-cancer activities, particularly for the novel treatment protocols involving injections of cytotoxic compounds directly into the tumor. This approach is increasingly applied to difficult-to-treat cancers, such as pancreatic cancer. The first study of in-vitro anti-cancer properties of a rare stable non-oxido V(V) complex, (NH4)[V(dtbc)3], where dtbcH2 is 3,5-di-tert-butylcatechol, was performed by a combination of end-point viability assays and real-time (IncuCyte) proliferation and cytotoxicity assays in human pancreatic cancer (PANC-1) cells. An improved synthetic procedure led to a nearly quantitative yield of the complex under ambient conditions. Reactions of (NH4)[V(dtbc)3] either in polar organic solvents or in neutral aqueous media led to the formation of V(V)-oxido-catecholato intermediates (characterized by electrospray mass spectrometry) that were responsible for its anti-proliferative and cytotoxic (apoptotic or necrotic) activity (IC50, 3.5-18 µM V in 72 h assays). These results demonstrate the link between solution speciation and biological activity of V complexes. Reaction of (NH4)[V(dtbc)3] with human serum albumin (HSA) in aqueous media led to the formation of protein-bound V(V) oxido-catecholato species that showed high anti-proliferative activity (IC50 ~10 µM V) combined with low cytotoxicity. Formation of HSA adducts of hydrophobic V complexes, such as (NH4)[V(dtbc)3], is a promising way to achieve their sustained delivery to cancer tumors.

Rational design and facile synthesis of binary metal sulfides VS2-SnS2 hybrid with functionalized multiwalled carbon nanotube for the selective detection of neurotransmitter dopamine.

In this work, we report a sensitive and selective electrochemical sensor for the detection of dopamine (DA) neurotransmitter based on VS2-SnS2/f-MWCNT hybrids. Herein, the binary metal sulfide (VS2-SnS2) was synthesized via single step hydrothermal route and hybrids with f-MWCNT via the ultrasonication process. The as-prepared VS2-SnS2/f-MWCNT hybrids were characterized through the FESEM, EDX and elemental mapping, TEM, XPS, Raman and XRD techniques. The electrochemical performance and catalytic activity of the modified electrodes were probed using electrochemical impedance spectra (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Interestingly, DPV results exhibits an appreciable linear range from 0.025 to 1017 µM and LOD of 0.008 µM. The selectivity study was performed to prove the high selectivity of the VS2-SnS2/f-MWCNT hybrids modified electrode. Furthermore, the practical applicability of the DA sensor was scrutinized in human serum sample and rat brain sample.

Highly Sensitive, Temperature-Independent Oxygen Gas Sensor Based on Anatase TiO2 Nanoparticle Grafted, 2D Mixed Valent VO x Nanoflakelets.

Herein, we report a facile approach for the synthesis of TiO2 nanoparticles tethered on 2D mixed valent vanadium oxide (VO x/TiO2) nanoflakelets using a thermal decomposition assisted hydrothermal method and investigation of its temperature-independent performance enhancement in oxygen-sensing properties. The material was structurally characterized using XRD, TEM, Raman, DSC, and XPS analysis. The presence of mixed valent states, such as V2O5 and VO2 in VO x, and the metastable properties of VO2 have been found to play crucial roles in the temperature-independent electrical conductivity of VO x/TiO2 nanoflakelets. Though pristine VO x exhibited characteristic semiconductor-to-metal transition of monoclinic VO2, pure VO x nanoflakelets exhibited poor sensitivity toward sensing oxygen. VO x/TiO2 nanoflakelets showed a very low temperature coefficient of resistance above 150 °C with improved sensitivity (35 times higher than VO x for 100 ppm) toward oxygen gas. VO x/TiO2 nanoflakelets exhibited much higher response, faster adsorption and desorption toward oxygen as compared to pristine VO x beyond 100 °C, which endowed the sensor with excellent temperature-independent sensor properties within 150-500 °C. The faster adsorption and desorption after 100 °C led to shorter response time (3-5 s) and recovery time (7-9 s). The results suggest that 2D VO x/TiO2 can be a promising candidate for temperature-independent oxygen sensor applications.

Decoding the anticancer activity of VO-clioquinol compound: the mechanism of action and cell death pathways in human osteosarcoma cells.

Vanadium compounds were studied in recent years by considering them as a representative of a new class of non-platinum metal anticancer drugs. However, a few challenges still remain in the discovery of new molecular targets of these new metallodrugs. Studies on cell signaling pathways related to vanadium compounds have scarcely been reported and so far this information is highly critical for identifying novel targets that play a key role in the antitumor actions of vanadium complexes. This research deals with the alterations in the intracellular signaling pathways promoted by an oxovanadium(iv) complex with the clioquinol (5-chloro-7-iodo-8-quinolinol), VO(CQ)2, on a human osteosarcoma cell line (MG-63). Herein are reported, for the first time, the antitumor properties of VO(CQ)2 and the relative abundance of 224 proteins (which are involved in most of the common intracellular pathways) to identify novel targets of the studied complex. Besides, full-length human recombinant AKT1 kinase was produced by using an IVTT system to evaluate the variation of relative tyrosin-phosphorylation levels caused by this compound. The results of the differential protein expression levels reveal several up-regulated proteins such as CASP3, CASP6, CASP7, CASP10, CASP11, Bcl-x, DAPK and down-regulated ones, such as PKB/AKT, DIABLO, among others. Moreover, cell signaling pathways involved in several altered pathways related to the PKC and AP2 family have been identified in both treatments (2.5 and 10 µM) suggesting the crucial antitumoral role of VO(CQ)2. Finally, it has been demonstrated that this compound (10 µM, 6 h) triggers a decrease of 2-fold in in situ AKT1 expression.

A Small Insulinomimetic Molecule Also Improves Insulin Sensitivity in Diabetic Mice.

Dramatic increase of diabetes over the globe is in tandem with the increase in insulin requirement. This is because destruction and dysfunction of pancreatic ß-cells are of common occurrence in both Type1 diabetes and Type2 diabetes, and insulin injection becomes a compulsion. Because of several problems associated with insulin injection, orally active insulin mimetic compounds would be ideal substitute. Here we report a small molecule, a peroxyvanadate compound i.e. DmpzH[VO(O2)2(dmpz)], henceforth referred as dmp, which specifically binds to insulin receptor with considerable affinity (KD-1.17µM) thus activating insulin receptor tyrosine kinase and its downstream signaling molecules resulting increased uptake of [14C] 2 Deoxy-glucose. Oral administration of dmp to streptozotocin treated BALB/c mice lowers blood glucose level and markedly stimulates glucose and fatty acid uptake by skeletal muscle and adipose tissue respectively. In db/db mice, it greatly improves insulin sensitivity through excess expression of PPARγ and its target genes i.e. adiponectin, CD36 and aP2. Study on the underlying mechanism demonstrated that excess expression of Wnt3a decreased PPARγ whereas dmp suppression of Wnt3a gene increased PPARγ expression which subsequently augmented adiponectin. Increased production of adiponectin in db/db mice due to dmp effected lowering of circulatory TG and FFA levels, activates AMPK in skeletal muscle and this stimulates mitochondrial biogenesis and bioenergetics. Decrease of lipid load along with increased mitochondrial activity greatly improves energy homeostasis which has been found to be correlated with the increased insulin sensitivity. The results obtained with dmp, therefore, strongly indicate that dmp could be a potential candidate for insulin replacement therapy.

Bisperoxovandium (pyridin-2-squaramide) targets both PTEN and ERK1/2 to confer neuroprotection.

BACKGROUND AND PURPOSE: We and others have shown that inhibiting phosphatase and tensin homolog deleted on chromosome 10 (PTEN) or activating ERK1/2 confer neuroprotection. As bisperoxovanadium compounds are well-established inhibitors of PTEN, we designed bisperoxovandium (pyridin-2-squaramide) [bpV(pis)] and determined whether and how bpV(pis) exerts a neuroprotective effect in cerebral ischaemia-reperfusion injury. EXPERIMENTAL APPROACH: Malachite green-based phosphatase assay was used to measure PTEN activity. A western blot assay was used to measure the phosphorylation level of Akt and ERK1/2 (p-Akt and p-ERK1/2). Oxygen-glucose deprivation (OGD) was used to injure cultured cortical neurons. Cell death and viability were assessed by LDH and MTT assays. To verify the effects of bpV(pis) in vivo, Sprague-Dawley rats were subjected to middle cerebral artery occlusion, and brain infarct volume was measured and neurological function tests performed. KEY RESULTS: bpV(pis) inhibited PTEN activity and increased p-Akt in SH-SY5Y cells but not in PTEN-deleted U251 cells. bpV(pis) also elevated p-ERK1/2 in both SH-SY5Y and U251 cells. These data indicate that bpV(pis) enhances Akt activation through PTEN inhibition but increases ERK1/2 activation independently of PTEN signalling. bpV(pis) prevented OGD-induced neuronal death in vitro and reduced brain infarct volume and promoted functional recovery in stroke animals. This neuroprotective effect of bpV(pis) was blocked by inhibiting Akt and/or ERK1/2. CONCLUSIONS AND IMPLICATIONS: bpV(pis) confers neuroprotection in OGD-induced injury in vitro and in cerebral ischaemia in vivo by suppressing PTEN and activating ERK1/2. Thus, bpV(pis) is a bi-target neuroprotectant that may be developed as a drug candidate for stroke treatment.

Synthesis and Electrochemical Properties of Nano-VO2 (B).

The nano-VO2 (B) has been self-assembly synthesized by hydrothermal method using different templates, which may give them some interesting properties. The as-prepared samples were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical properties of the samples were investigated. The results show that the hexadecyltrimethyl ammonium bromide (CTAB) (soft template) was used to obtain the VO2 (B1) nanobelts. The flake graphite (hard template) was taken to get the VO2 (B2) nanosheets. The VO2 (B1) nanobelts have higher initial capacity to compare with VO2 (B2). But the VO2 (B2) nanosheets showed better cycling performance than that of VO2 (B1) nanobelts. The nano VO2 (B2) is a promising anode material for lithium ion battery application.

Rapid mechanochemical synthesis of VOx/TiO2 as highly active catalyst for HCB removal.

A rapid (1.5h) one-step ball milling (BM) method was developed to synthesize VOx/TiO2 (VTi-BM) and WOx or MoOx doped VOx/TiO2 (VWTi-BM or VMoTi-BM). Catalytic activity on gaseous POPs removal was tested using hexachlorobenzene (HCB) as surrogate. Catalytic performance decreased in the order of VWTi-BM (T50%=230°C)>VMoTi-BM (260°C)>VTi-BM (270°C)>VTi-WI (300°C; VOx/TiO2 synthesized by wetness impregnation method). The intermediates from oxidation of HCB were analyzed by off gas analysis, from which 2,2,4,5-tetrachloro-4-cyclopentene-1,3-dione (TCCD), dichloromaleic anhydride (DCMA) and tetrachloro-1,4-bezoquinone (TCBQ) were identified. Furthermore, a possible mechanism for the oxidation of HCB over VOx/TiO2 catalysts was proposed. Mechanism studies showed that BM samples possess better dispersion of the VOx species and more surface chemisorbed oxygen. Doping WOx or MoOx into VOx/TiO2 by ball milling can further enhance catalytic performance by increasing surface acid sites.

Synthesis, Characterization, Antioxidant Status, and Toxicity Study of Vanadium-Rutin Complex in Balb/c Mice.

A new trend was developed for the formation of a complex between vanadium and flavonoid derivatives in order to increase the intestinal absorption and to reduce the toxicity of vanadium compounds. The vanadium-rutin complex was characterized by several spectroscopic techniques like ultraviolet (UV)-visible, Fourier transform infrared (FTIR), NMR, mass spectrometry, and microscopic evaluation by scanning electron microscopy. The mononuclear complex was formed by the interaction between vanadium and rutin with 1:2 metal to ligand stoichiometry. Antioxidant activity of the complex was evaluated by 1,1-diphenyl-2 picrylhydrazyl, ferric-reducing power, and 2,2'-azin-obis 3-ethylbenzothiazoline-6-sulphonic acid methods. It was shown that radical scavenging activity and ferric-reducing potential of free rutin was lower as compared with vanadium-rutin complex. The study was also investigated for oral acute toxicity and 28 days repeated oral subacute toxicity study of vanadium-rutin complex in balb/c mice. The vanadium-rutin complex showed mortality at a dose of 120 mg/kg in the balb/c mice. In 28 days repeated oral toxicity study, vanadium-rutin complex was administered to both sex of balb/c mice at dose levels of 90, 45, and 20 ppm, respectively. In addition, subacute toxicity study of vanadium-rutin complex (at 90 ppm dose level) showed increase levels of white blood cell (WBC), total bilirubin, alanine aminotransferase (ALT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), creatinine, and blood urea nitrogen and decrease level of total protein (TP) as compared with control group. Histopathological study of vanadium-rutin showed structural alteration in the liver, kidney, and stomach at 90 ppm dose level. No observed toxic level of vanadium-rutin complex at 20 ppm dose level could be good for further study.

[The vanadium compounds: chemistry, synthesis, insulinomimetic properties].

The review considers the biological role of vanadium, its participation in various processes in humans and other mammals, and the anti-diabetic effect of its compounds. Vanadium salts have persistent hypoglycemic and antihyperlipidemic effects and reduce the probability of secondary complications in animals with experimental diabetes. The review contains a detailed description of all major synthesized vanadium complexes having antidiabetic activity. Currently, vanadium complexes with organic ligands are more effective and safer than the inorganic salts. Despite the proven efficacy of these compounds as the anti-diabetic agents in animal models, only one organic complex of vanadium is currently under the second phase of clinical trials. All of the considered data suggest that vanadium compound are a new promising class of drugs in modern pharmacotherapy of diabetes.

Effects of heteroatoms on electronic states of divanadium-substituted γ-Keggin-type polyoxometalates.

Effects of heteroatoms on electronic states of divanadium-substituted γ-Keggin-type polyoxometalates (TBA)4[γ-XV2W10O38(µ-OH)(µ-OR)] (X = Ge, Si; R = Me, Et, n-Pr, H; TBA = tetra(n-butyl)ammonium) and (TBA)4[γ-XV2W10O38(µ-O)] (X = Ge, Si) were investigated, using a combination of nuclear magnetic resonance spectroscopy and density functional theory (DFT) calculations. Both the substitution of SiO4 heteroatom units with larger GeO4 ones and the introduction of more electronegative alkoxo groups in place of hydroxo groups resulted in deshielding of the vanadium nuclei. DFT calculations using the Def2-SVP basis set at TPSSh level of theory could well-reproduce the anionic moieties of a series of divanadium-substituted γ-Keggin-type polyoxometalates, and the estimated chemical shifts approximately reproduced the experimental ones with the individual gauge localized orbital method (SO-IGLO) taking the spin-orbit interaction into account. The magnetic shielding (σ) consists of σd + σp + σSD + σFC, where σd, σp, σSD, and σFC are diamagnetic, paramagnetic, spin-dipolar, and Fermi contact terms, respectively. The σp changed much among (TBA)4[γ-XV2W10O38(µ-OH)2], (TBA)4[γ-XV2W10O38(µ-OH)(µ-OR)], and (TBA)4[γ-XV2W10O38(µ-O)], while σd, σSD, and σFC did not change much. Therefore, the σp largely contributed to the magnetic shielding. Moreover, σp consisted of the occupied-occupied transitions (s-terms) and the occupied-virtual ones (u-terms), and the u-terms were predominant for σp. The most contributing occupied localized orbital consisted of the dz(2) orbital of vanadium, the pz orbital of terminal oxygen related to the V═O bond, and the pz orbital of oxygen of the XO4 unit, whereas the two virtual localized orbitals consisted of the dyz orbital of vanadium and the py orbital of terminal oxygen. Analysis of the structural and electronic characteristics of a series of divanadium-substituted γ-Keggin-type POMs revealed a linear correlation between both (51)V{H} chemical shifts and the reciprocal values of the energy gaps between the corresponding XO4-predominant orbital HOMOs-X and the LUMOs+X (X = 0, 1, or 2). All these results indicate that neighboring XO4 units weakly interact with the addenda atoms and control the electronic states of polyoxometalates and the magnetic shielding of their addenda atoms.

A green mesostructured vanadosilicate catalyst and its unprecedented catalytic activity for the selective synthesis of 2,6-disubstituted p-benzoquinones.

We have developed a green method for the production of 2,6-disubstituted p-benzoquinones (DSBQs) by liquid-phase oxidations of di/tri-substituted phenols using two-dimensional hexagonally thick-walled mesoporous vanadosilicate catalysts. In particular, 2,6-di-tert-butyl-p-benzoquinone was synthesized by the oxidation of 2,6-di-tert-butylphenol, using various reaction parameters, over mesoporous VSBA-15 catalysts synthesized with various vanadium contents. A promising chemical treatment method for the preparation of green mesoporous VSBA-15(5) or W-VSBA-15(5) (W: washed) catalysts was successfully used in the presence of ammonium acetate solution to remove moderately toxic non-framework V2O5 crystallite species from the active surface, and the catalytic activity of the recovered green mesoporous VSBA-15(5) catalyst was determined. To confirm the green aspects, recyclability and hot-catalytic filtration experiments were performed. The combined results show that the green mesoporous VSBA-15(5) is a highly active, recyclable, and promising heterogeneous catalyst for the selective synthesis of DSBQs (98-100%), and has unprecedented catalytic activity compared with other mesoporous vanadosilicate catalysts.

A bioinspired solution for spectrally selective thermochromic VO2 coated intelligent glazing.

We present a novel approach towards achieving high visible transmittance for vanadium dioxide (VO(2)) coated surfaces whilst maintaining the solar energy transmittance modulation required for smart-window applications. Our method deviates from conventional approaches and utilizes subwavelength surface structures, based upon those present on the eyeballs of moths, that are engineered to exhibit broadband, polarization insensitive and wide-angle antireflection properties. The moth-eye functionalised surface is expected to benefit from simultaneous super-hydrophobic properties that enable the window to self-clean. We develop a set of design rules for the moth-eye surface nanostructures and, following this, numerically optimize their dimensions using parameter search algorithms implemented through a series of Finite Difference Time Domain (FDTD) simulations. We select six high-performing cases for presentation, all of which have a periodicity of 130 nm and aspect ratios between 1.9 and 8.8. Based upon our calculations the selected cases modulate the solar energy transmittance by as much as 23.1% whilst maintaining high visible transmittance of up to 70.3%. The performance metrics of the windows presented in this paper are the highest calculated for VO(2) based smart-windows.

Synthesis, characterization and cell viability test of six vanadyl complexes with acetylacetonate derivatives.

Vanadium compounds are known to display a number of therapeutic effects, namely insulin-mimetic and cardiovascular effects. Evidence of the antiproliferative and proapoptotic activity of a number of vanadyl complexes, together with their low toxicity, establishes these metal compounds as promising antitumoral therapeutic agents. In the present work, we describe the synthesis and full characterization of six new vanadyl complexes with acetylacetonate derivatives bearing asymmetric substitutions on the ß-dicarbonyl moiety: the complexes were characterized in the solid state as well as in solution. Our results show that all complexes are in square pyramidal geometry; cis isomers in the equatorial plane are favored in the presence of strongly coordinating solvents. EPR evidence suggests that all complexes are in the bis-chelate form, although in two cases the mono-chelated complex seems to be present as well. Preliminary tests carried out on non-tumor and tumor cell lines show that these complexes are effective in suppressing cell viability and elicit a distinct response of tumor and non-tumor cells.

Synthesis, structures and properties of the catalytic bromination reaction of a series of novel scorperate oxidovanadium complexes with the potential detection of hydrogen peroxide in water.

A series of scorpionate oxovanadium (IV) complexes: [VO(Tp(4I))(pz)(SCN)]·1/2CH2Cl2 (1), [VO(Tp)(pzTp)]·2H2O (2), [VO(Bp)(Tp(4I))] (3) and [VO(C5H7O2)(Tp(4I))]·CH3OH (4) (Bp: [H2B(pz)(2-)], Tp: [HB(pz)(3-)], Tp(4I): [HB(4I-pz)(3-)], pzTp: [B(pz)(4-)]) have been synthesized and characterized by elemental analysis, IR spectra, UV-Vis spectroscopy, powder X-ray diffraction, single-crystal X-ray diffraction and thermal gravimetric analysis (TG). Structural analysis shows that the coordination environment of vanadium atom is N5O, to form a distorted octahedron geometry. In addition, the catalytic activities of the bromination reactions for complexes 1 and 2 in phosphate buffer with phenol red as a trap were evaluated primary by UV/Vis spectroscopy, and a practical application of H2O2 detection was firstly observed in the catalytic reaction system.

Synthesis and characterization of patronite form of vanadium sulfide on graphitic layer.

With the exploding interest in transition metal chalcogenides, sulfide minerals containing the dianion S2(2-), such as pyrite (FeS2), cattierite (CoS2), and vaesite (NiS2), have recently attracted much attention for potential applications in energy conversion and storage devices. However, the synthesis of the patronite structure (VS4, V(4+)(S2(2-))2) and its applications have not yet been clearly demonstrated because of experimental difficulties and the existence of nonstoichiometric phases. Herein, we report the synthesis of VS4 using a simple, facile hydrothermal method with a graphene oxide (GO) template and the characterization of the resulting material. Tests of various templates such as CNT, pyrene, perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA), and graphite led us to the conclusion that the graphitic layer plays a role in the nucleation during growth of VS4. Furthermore, the VS4/rGO hybrid was proved to be a promising functional material in energy storage devices.