Search

Comprehensive Summary: It remains an urgent task to develop alternative hole‐transporting layer (HTL) materials beyond commonly used PEDOT:PSS to increase the shelf‐life of organic solar cells (OSCs). Inorganic metal oxide type materials, such as NiOx, CoOx and VOx, with suitable work functions have attracted numerous research attention recently. In this work, more abundant and easily accessible oxygenated salt, vanadyl sulfate (VOSO4) has been demonstrated to be excellent choice as HTL for OSCs. The VOSO4‐based HTL can be readily processed by spin‐coating from the precursor solution with subsequent thermal annealing and UVO treatment. As a consequence, a high power conversion efficiency (PCE) of 18.72% can be achieved for PM8:L8‐BO based OSCs with the VOSO4‐based HTL. High transmittance, smooth film surface, suitable energy level and high conductivity were revealed to contribute to the high OSC performance. More importantly, compared to device with PEDOT:PSS, VOSO4‐based OSCs exhibit improved stability when stored in the N2 filled glove box. After being stored for 600 h, VOSO4‐based device can retain 89% of its initial efficiency. Notably, VOSO4 can be used as general HTL in PM6:BTP‐BO‐4Cl and PM6:IT‐4F based OSCs, yielding high PCEs of 17.87% and 13.85%, respectively. [ABSTRACT FROM AUTHOR]

This study explores the theoretical properties of a novel complex formed by combining vitamin E (VitE) and vanadyl(II) sulfate. The complex, [VO(VitE)2(H2O)2]2H2O (Vcom), was synthesized in solid form through a reaction between VitE and VOSO4.xH2O in a specific solvent mixture and pH. VitE binds to the vanadyl ion as a single ligand via its deprotonated phenolic oxygen. To characterize the complex, various analytical techniques were employed, including elemental analysis, spectral analysis, conductivity measurements, thermal analysis, X-ray diffraction, and microscopy. Electronic and magnetic properties were also investigated. Theoretical calculations - molecular docking simulations were used to assess the binding affinity of Vcom with two receptors known to interact with vitamin E: α-tocopherol transfer protein (α-TTP) and p105 subunit of nuclear factor NFkappa-B p105 subunit (NF-κB). The findings revealed a square pyramidal geometry for the Vcom complex. Additionally, Density Functional Theory (DFT) were performed on both VitE and Vcom, focusing on their optimized structures, electrostatic properties, and HOMO-LUMO energy gaps. In summary, this research delves into the theoretical aspects of a newly formed VitE-vanadyl complex, providing insights into its structure, properties, and potential interactions with relevant receptors. [ABSTRACT FROM AUTHOR]

Herein, an accurate and simple spectrophotometric method for investigating cefixime in different formulations is reported. The proposed method elaborates on the complexation of cefixime with vanadyl sulfate in acidic media. The yellow color complexation product manifested its maximum absorbance peak at around 321 nm, and obeyed Beer's law in 2 × 10−6–1 × 10−4 M cefixime concentration. Obtained spectroscopic data were used to calculate standard deviation (S), limit of detection (LOD), limit of quantification (LOQ), and relative standard deviation (RSD) as 6.5 × 10−5, 1.96 × 10−4, 6.5 × 10−4 M, and 0.057%, respectively. In addition, the formation constant associated with the complex obtained, calculated as 5.7 × 1016, indicates that the final complex was remarkably stable. [ABSTRACT FROM AUTHOR]

Vanadyl sulfate (VS), is a component of some food supplements and experimental drugs. This study was carried out to present a novel method for induction of Type 2 diabetes in rats, then for the first time in literature, for evaluating the effect of VS on metabolic parameters and gene expression, simultaneously. 40 male wistar rats were distributed between the four groups, equally. High fat diet and fructose were used for diabetes induction. Diabetic rats treated by two different dose of VS for 12 weeks. Metabolic profiles were evaluated by commercial available kits and gene expression were assayed by real time-PCR. Compared to controls, in non-treated diabetic rats, weight, glucose, triglyceride, total cholesterol, insulin and insulin resistance were increased significantly (p-value <0.05) that indicated induction of type 2 diabetes. Further, the results showed that VS significantly reduced weight, insulin secretion, Tumor Necrosis Factor-alpha (TNF-α) genes expression, lipid profiles except HDL that we couldn't find any significant change and increased Peroxisome Proliferator-Activated Receptor- gamma (PPAR-γ) gene expression in VS-treated diabetic animals in comparison with the non-treated diabetics. Our study demonstrated that vanadyl supplementation in diabetic rats had advantageous effects on metabolic profiles and related gene expression. [ABSTRACT FROM AUTHOR]

Oncolytic viruses (OVs) are promising anticancer treatments that specifically replicate in and kill cancer cells and have profound immunostimulatory effects. We previously reported the potential of vanadium-based compounds such as vanadyl sulfate (VS) as immunostimulatory enhancers of OV immunotherapy. These compounds, in conjunction with RNAbased OVs such as oncolytic vesicular stomatitis virus (VSV🜂51), improve viral spread and oncolysis, leading to long-term antitumor immunity and prolonged survival in resistant tumor models. This effect is associated with a virus-induced antiviral type I IFN response shifting towards a type II IFN response in the presence of vanadium. Here, we investigated the systemic impact of VS+VSV🜂51 combination therapy to understand the immunological mechanism of action leading to improved antitumor responses. VS+VSV🜂51 combination therapy significantly increased the levels of IFN-γ and IL-6, and improved tumor antigenspecific T-cell responses. Supported by immunological profiling and as a proof of concept for the design of more effective therapeutic regimens, we found that local delivery of IL-12 using VSVD51 in combination with VS further improved therapeutic outcomes in a syngeneic CT26WT colon cancer model. [ABSTRACT FROM AUTHOR]

Oncolytic viruses (OVs) are promising anticancer treatments that specifically replicate in and kill cancer cells and have profound immunostimulatory effects. We previously reported the potential of vanadium-based compounds such as vanadyl sulfate (VS) as immunostimulatory enhancers of OV immunotherapy. These compounds, in conjunction with RNA-based OVs such as oncolytic vesicular stomatitis virus (VSVΔ51), improve viral spread and oncolysis, leading to long-term antitumor immunity and prolonged survival in resistant tumor models. This effect is associated with a virus-induced antiviral type I IFN response shifting towards a type II IFN response in the presence of vanadium. Here, we investigated the systemic impact of VS+VSVΔ51 combination therapy to understand the immunological mechanism of action leading to improved antitumor responses. VS+VSVΔ51 combination therapy significantly increased the levels of IFN-γ and IL-6, and improved tumor antigen-specific T-cell responses. Supported by immunological profiling and as a proof of concept for the design of more effective therapeutic regimens, we found that local delivery of IL-12 using VSVΔ51 in combination with VS further improved therapeutic outcomes in a syngeneic CT26WT colon cancer model.

The composition of the product formed in the V2O5–H2SO4–SO3–H2O system and its thermal decomposition are studied by differential thermal analysis, thermogravimetry, X-ray diffraction analysis, IR spectroscopy, scanning electron microscopy, and energy dispersive X-ray analysis. As found by X-ray diffraction, the formed deposit corresponds to vanadyl sulfate VOSO4⋅3H2O. The study of the thermal decomposition of VOSO4⋅3H2O by derivatography, IR spectroscopy, scanning electron microscopy, and energy dispersive X-ray analysis shows that the decomposition of vanadyl sulfate is multistage and occurs with the formation of intermediate phases. [ABSTRACT FROM AUTHOR]

The catalytically active vanadium-containing system of γ-Al2O3 was studied using a wide range of physical and chemical methods, depending on the synthesis conditions. It is shown that the vanadium-containing system includes several complexes with different thermal stabilities and catalytic activities. Low-active complexes are destroyed with the formation of more active ones based on V2O5 oxide, as the temperature of heat treatment increases. It can be assumed that V2O5 oxide has the decisive role in its catalytic activity. It was concluded that the vanadium-containing catalytic system on aluminium oxide, in the studied temperature range, is thermally stable and shows high activity not only in the reduction of nitrogen oxides but also in the oxidation of hydrocarbons (even of the most difficult ones, such as oxidizable methane). These properties of the system make it quite promising in the field of application for the purification of the exhaust gases of motor transport and industrial enterprises with environmentally harmful components, as well as for understanding the mechanism of the action of the catalysts in these processes, which is very important for solving the problems of decarbonization and achieving carbon neutrality. [ABSTRACT FROM AUTHOR]

Nephrotoxicity becomes a provoked problem as the kidneys are the target of many chemotherapies. For this reason, we aimed to study the protective effect of Galaxaura elongata extract (GE) against the vanadyl sulfate (Van) induced nephrotoxicity in rats. Forty Wistar albino rats (male) were divided into four groups (n = 10) as follows: control group: rats received 0.5% carboxymethyl cellulose (CMC). Galaxa group: rats received GE at a dose (100 mg/kg orally) daily for 6 weeks. Van group: rats injected with Van at a dose (50 mg/kg i.p.) once weekly for 6 successive weeks. Galaxa + Van group: rats received GE at a dose (100 mg/kg orally) daily for 6 weeks concurrently with Van at a dose (50 mg/kg i.p.) for 6 weeks. Our results showed that Van significantly raised urea and creatinine serum levels as compared to the control group as well as disordered renal oxidative/antioxidant redox. Administration of GE with Van alleviated the adverse impact of Van over the kidney tissues. Furthermore, GE administration in Galaxa + Van group downregulates angiotensin-converting enzyme (ACE1) mRNA expression, angiotensin II (Ang II) concentration, transforming growth factor β (TGF-β) mRNA expression and protein concentration and Nuclear factor κB (NF-κB) mRNA expression as compared to Van group. Also, GE administration caused a noticeable upregulation of Nrf2 and heme oxygenase-1 (HO-1) expressions with a consequent decrease of DNA fragmentation % compared to Van group. The results of the current study show that simultaneous treatment with GE can alleviate nephrotoxicity caused by Van in diabetic rats. The GE treatment of the Van treated animals restored altered renal oxidative/antioxidant redox values towards normal and lessened fibrosis. These results are consistent with these effects being caused by interactions with the TGF-B/Smads and Nrf2/NF-κB signaling pathways. [ABSTRACT FROM AUTHOR]

Vanadium is a ubiquitous environmental contaminant although there are limited data to assess potential adverse human health impact following oral exposure. In support of studies investigating the subchronic toxicity of vanadyl sulfate (V4+) and sodium metavanadate (V5+) following perinatal exposure via drinking water in male and female rats, we have determined the internal exposure and urinary excretion of total vanadium at the end of study. Water consumption decreased with increasing exposure concentration following exposure to both compounds. Plasma and urine vanadium concentration normalized to total vanadium consumed per day increased with the exposure concentration of vanadyl sulfate and sodium metavanadate suggesting absorption increased as the exposure concentration increased. Additionally, females had higher concentrations than males (in plasma only for vanadyl sulfate exposure). Animals exposed to sodium metavanadate had up to 3-fold higher vanadium concentration in plasma and urine compared to vanadyl sulfate exposed animals, when normalized to total vanadium consumed per day, demonstrating differential absorption, distribution, metabolism, and excretion properties between V5+ and V4+ compounds. These data will aid in the interpretation of animal toxicity data of V4+ and V5+ compounds and determine the relevance of animal toxicity findings to human exposures. • Vanadium (V) is a ubiquitous environmental contaminant. • Internal exposure was determined in rodents after oral exposure to V4+ and V5+. • Plasma and urine V levels increased more than proportional to V4+ and V5+ dose. • Exposure to V5+ caused up to 3-fold higher plasma and urine V levels than V4+. • Data demonstrate differential ADME properties between V5+ and V4+ compounds. [ABSTRACT FROM AUTHOR]

The avian paramyxovirus, Newcastle disease virus (NDV), is a promising oncolytic agent that has been shown to be safe and effective in a variety of pre-clinical cancer models and human clinical trials. NDV preferentially replicates in tumor cells due to signaling defects in apoptotic and antiviral pathways acquired during the transformation process and is a potent immunostimulatory agent. However, when used as a monotherapy NDV lacks the ability to consistently generate durable remissions. Here we investigate the use of viral sensitizer-mediated combination therapy to enhance the anti-neoplastic efficacy of NDV. Intratumoral injection of vanadyl sulfate, a pan-inhibitor of protein tyrosine phosphatases, in combination with NDV significantly increased the number and activation status of natural killer (NK) cells in the tumor microenvironment, concomitant with increased expression of interferon-β, granulocyte-macrophage colony-stimulating factor, and monocyte chemoattractant protein-1, leading to rapid tumor regression and long-term cures in mice bearing syngeneic B16-F10 melanomas. The anti-tumor efficacy of this combination therapy was abrogated when NK cells were depleted and when interferon-β expression was transiently suppressed. Tumor-specific CD8+ T cell responses were not detected, nor were mice whose tumors regressed protected from re-challenge. This suggested efficacy of the combination therapy predominantly relied on the innate immune system. Importantly, efficacy was not limited to melanoma; it was also demonstrated in a murine prostate cancer model. Taken together, these results suggest that combining NDV with vanadyl sulfate potentiates an innate immune response that can potentiate rapid clearance of tumors, with type I interferon signaling and NK cells being important mechanisms of action.

The catalytically active vanadium-containing system of γ-Al2O3 was studied using a wide range of physical and chemical methods, depending on the synthesis conditions. It is shown that the vanadium-containing system includes several complexes with different thermal stabilities and catalytic activities. Low-active complexes are destroyed with the formation of more active ones based on V2O5 oxide, as the temperature of heat treatment increases. It can be assumed that V2O5 oxide has the decisive role in its catalytic activity. It was concluded that the vanadium-containing catalytic system on aluminium oxide, in the studied temperature range, is thermally stable and shows high activity not only in the reduction of nitrogen oxides but also in the oxidation of hydrocarbons (even of the most difficult ones, such as oxidizable methane). These properties of the system make it quite promising in the field of application for the purification of the exhaust gases of motor transport and industrial enterprises with environmentally harmful components, as well as for understanding the mechanism of the action of the catalysts in these processes, which is very important for solving the problems of decarbonization and achieving carbon neutrality.

Exposure to vanadium has been associated with deleterious effects on the central nervous system in animals and humans. Although vanadium‐derived pro‐oxidant species were reported to be involved in vanadium‐mediated neurotoxicity, the ability of this metal to induce oxidative stress markers in glial cells remains to be elucidated. In this study, we investigated the cytotoxicity and the generation of reactive oxygen species (ROS) and nitric oxide (NO) by mouse primary astrocytes after treatment with vanadyl sulfate (VOSO4) at concentrations of 20, 50, 100, 200, and 500 μM. The resazurin assay revealed that treatment with VOSO4 for 24 and 48 h at concentrations of 50 and 100 μM, respectively, or higher substantially induced astrocytic cytotoxicity. Intracellular ROS increased after 6‐h exposure to the lowest concentration tested (20 μM VOSO4) and tended to intensify after 24‐ and 48‐h treatments reaching significant values for 20 and 500 μM VOSO4. In turn, NO production in the examined cells was elevated after exposure to all concentrations at the 6‐, 24‐, and 48‐h incubation periods. Our study demonstrated the ability of VOSO4 to induce H2O2 generation in cell‐free DMEM/F12 medium. The H2O2 levels were in the micromolar range (up to 5 μM) and were detected mostly during the first few minutes after VOSO4 addition, suggesting that the generated H2O2 could not induce toxic effects on the cells. Taken together, these results show VOSO4 induced cytotoxicity in primary astrocyte cells, which may have resulted from vanadyl‐stimulated intracellular ROS and NO generation in these cells. The regression analysis for the levels of H2O2 produced by VOSO4 in the culture medium showed that 86% and 85% of the variation in the concentration of H2O2 (measured after the 0‐ and 5‐min incubation with VOSO4, respectively) was determined by vanadium. [ABSTRACT FROM AUTHOR]

Vanadium/L-cysteine (V/L-cys) hybrid films with favorable anti-corrosion performance were fabricated on copper substrate based on the coordination between Vanadium and L-cys. The characteristic adsorption of sulfhydryl groups (-SH) in L-cys on copper acts as a bridge for film formation, while the coordination between VO2+ ions and –COOH or NH 2 in L-cys repairs defects and enhances the density of film. The EIS results indicated that the corrosion protection efficiency of V/L-cys film was 99.6 %, which was much higher than that of single L-cys film (91.1 %). Moreover, the immersion test exhibited that V/L-cys film was capable of enduring 300 min of immersion in a 3.5 % NaCl solution, whereas L-cys film could only withstand 60 min of immersion. The durability of V/L-cys film showed a significantly higher level than that of L-cys film. [Display omitted] • A hybrid conversion film was fabricated on the copper surface. • Coordination between VO2+ and L-cys improve the performances of hybrid film. • The corrosion protection efficiency of V/L-cys film was 99.6 %. • The V/L-cys film exhibited excellent durability in NaCl solution. [ABSTRACT FROM AUTHOR]

Background: Vanadyl sulphate is available as herbal medicine against diabetes mellitus and body building supplement, over the counter worldwide. The available data on its safety is controversial and inadequate. The objective of this study was to analyse its safety in usual therapeutic dose range. Methods: It was an experimental study carried out at the Department of Biochemistry & Molecular Biology, Army Medical College, National University of Medical Sciences (NUMS), Rawalpindi, Pakistan, from Jun 2014 to Oct 2018. The study was carried out on 105 Sprague Dawley rats for duration of 24 weeks. The animals were randomly distributed in three groups of 35 each. The group I rats were marked as control while rats of group II & III were administered vanadyl sulphate 0.06mg/day and 0.3mg/day respectively. Alanine amino transferase (ALT) and Malondialdehyde (MDA) were measured in serum while comet assay was performed on WBCs. Results: The plasma levels of ALT and MDA were significantly raised in group II and III subjects. Single cell gel electrophoresis (SCGE) / comet assay showed minimal "tail moment" in control group and increased tail moment in group II and III in a dose dependent manner which indicates dsDNA breaks. Conclusion: It was observed that vanadyl sulphate causes hepatocellular toxicity, oxidative stress and damage to the DNA in usual therapeutic/supplemental doses. Due to hazardous effects, its use in humans as alternate medicine may be reviewed. [ABSTRACT FROM AUTHOR]

We report Raman spectral studies of pure potassium oxalate monohydrate, K2C2O4 · H2O (POM) and its doped varieties with 1 and 5% vanadyl concentrations at room temperature. Apart from many other interesting changes in the Raman spectra on doping with VO2+, one of the most intriguing observations is the change in relative intensities of factor group split components of several Raman bands including some bands in the lattice mode region. We have explained the relative intensity changes of factor group split components in terms of locking of adjacent C2O4−H2O−C2O4−H2O chains due to vanadyl doping in the POM lattice. The reduction in the intensities of water bands on vanadyl doping also supports this view. [ABSTRACT FROM AUTHOR]

Highlights • Viscosity and density for aqueous VOSO 4 + H 2 SO 4 system was determined. • The viscosity coefficients – B i and Δ μ i ≠0 were estimated. • A predicting function of the viscosity for mixed electrolyte. Abstract Viscosities of ternary mixtures of VOSO 4 + H 2 SO 4 with water were measured across the entire range of total ionic strength (I T = 1 to 11) mol·kg−1 and over a temperature range of (283.15–318.15) K. The viscosity B -coefficients of the binary aqueous were determined from Jones-Dole equation. Using the B -coefficients, the activation parameters for viscous flow of the solutes were further evaluated. On the basis of Eyring's equation, a semi-empirical method to estimate the viscosity for concentrated and mixed electrolyte solutions was put forward. The estimated viscosity values of VOSO 4 + H 2 SO 4 + H 2 O are in quite good agreement with the corresponding experimental results with the average absolute relative deviation of 0.96%. [ABSTRACT FROM AUTHOR]

Highlights • Vanadium (IV) sulfate VOSO 4 and vanadium (V) pentoxide V 2 O 5 dissolution. • Temporal evolution of the concentrations of VO2+ and VO 2 + at various temperatures. • Understanding the dissolution limitations: VIV → mass transfer; VV → reaction with H+. • Simple kinetic models to predict the evolution of VO2+ and VO 2 + concentrations. Abstract The study deals with the 'vanadium (IV) sulfate' and 'vanadium (V) pentoxide' dissolution processes in 3 M H 2 SO 4 aqueous media. Several measurements of the concentration of dissolved VO2+ and VO 2 + were achieved in the range of 0–40 °C, and allowed to understand the limitations of the dissolution process ('endothermic' – mass transport for VOSO 4 and 'exothermic' – reaction with the proton for V 2 O 5). In addition, simple models were proposed (diffusion/accumulation for VOSO 4 and kinetic rate for V 2 O 5) and their resolution leads to theoretical kinetic equations describing the temporal evolution of these concentrations with satisfactory agreement with the experimental curves. Solubility's data and their temperature dependence were determined for both vanadium compounds involved. [ABSTRACT FROM AUTHOR]

Non‐small lung cell carcinoma has a high morbidity and mortality rates. The elective treatment for stage III and IV is cisplatinum that conveys serious toxic side effects. Vanadium compounds are metal molecules with proven antitumor activity that depends on its valence. Therefore, a better understanding of the mechanism of action of vanadium compounds is required. The aim of our study was to investigate the mechanisms of cell death induced by sodium metavanadate (NaVO3 [V(+5)]) and vanadyl sulfate (VOSO4 [(+4)]), both of which have reported apoptotic‐inducing activity. We exposed the A549 cell line to various concentrations (0‐100 μM) and to different exposure times to each compound and determined the cell viability and expression of caspases, reactive oxygen species (ROS) production, Bcl2, Bax, FasL and NO. Our results showed that neither compounds modified the basal expression of caspases or pro‐ and anti‐apoptotic proteins. The only change observed was the 12‐ and 14‐fold significant increase in ROS production induced by NaVO3 and VOSO4, respectively, at 100 μm concentrations after 48 hours. Our results suggest that classical apoptotic mechanisms are not related to the cell death induced by the vanadium compounds evaluated here, and showed that the higher ROS production was induced by the [(+4)] valence compound. It is possible that the difference will be secondary to its higher oxidative status and thus higher ROS production, which leads to higher cell damage. In conclusion, our results suggest that the efficacy of the cell death mechanisms induced by vanadium compounds differ depending on the valence of the compound. Lung cancer has a high mortality rate. In advanced stages, chemotherapy is the chosen treatment; however, toxic side effects are still a problem. Development of new molecules, which could overcome these disadvantages, should be a priority. Some metal compounds with proven antitumor activity, such as vanadium compounds, have been proven to inhibit the growth of cancer cells in vitro and in vivo assays. Therefore, a better understanding of the mechanism of action of vanadium compounds is required. [ABSTRACT FROM AUTHOR]

The reaction of VOSO4 with K2cbdc (cbdc2– is cyclobutane‐1,1‐dicarboxylate anion) and Ln(NO3)3 (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Tm, Yb, Lu) yielded 17 novel heterometallic LnIII‐VIV compounds comprising stable bis‐chelate units {VIVO(cbdc)2(H2O)}. Three structural types of compounds are formed depending on the nature of the rare‐earth metal: 1D polymers {[Ln(VO)(cbdc)2(H2O)7]·0.5[VO(cbdc)2]}n (structural type I) [Ln = La (1), Ce (2)], 3D polymers {[KLn(VO)2(cbdc)4(H2O)9]·3.5H2O}n (structural type II) [Ln = La (3), Ce (4), Pr (5), Nd (6), Sm (7), Eu (8), Gd (9), Tb (10), Dy (11), Ho (12)] comprising trinuclear units {LnV2}, and octanuclear complexes {[KLn(VO)2(cbdc)4(H2O)11]·2H2O}2 (structural type III) [Ln = Y (13), Er (14), Tm (15), Yb (16), Lu (17)] containing dinuclear units {LnV}. Magnetic properties were investigated for all isolated compounds. The GdIII‐VIV compound has ferromagnetic and antiferromagnetic exchange interactions between isotropic VIV and GdIII ions. Calculations using the DFT method at the UB3LYP/6‐31G(d,p)/SDD level of theory were performed in order to explain the different nature of exchange interactions in two GdIII‐VIV pairs. The YbIII‐VIV complex displays single‐molecule magnet properties; the effective energy barrier was estimated at ΔEeff/kB = 26 K. The magnetic properties of LnIII‐VIV compounds with heavy lanthanide ions (LnIII = Er, Tm, Yb) were rationalized in terms of crystal‐field calculations for LnIII ions. Three structural types of heterometallic LnIII‐VIV substituted malonates were synthesized from the bis‐malonate vanadyl unit and were characterized by single‐crystal and powder XRD and by magnetic measurements. The structures of the new compounds depend on the nature of the rare‐earth metal: a decrease in the LnIII ionic radius is accompanied by a decrease in the nuclearity of the {LnIII‐VIV} unit. [ABSTRACT FROM AUTHOR]

Reaction of differing amounts of vanadyl sulfate with p-tert-butylthiacalix[4]areneH4 and base allows access to the vanadyl-sulfate species [NEt4]4[(VO)4(μ3-OH)4(SO4)4]·½H2O (1), [HNEt3]5[(VO)5(μ3-O)4(SO4)4]·4MeCN (2·4MeCN) and [NEt4]2[(VO)6(O)2(SO4)4(OMe)(OH2)]·MeCN (3·MeCN). Similar use of p-tert-butylsulfonylcalix[4]areneH4, p-tert-butylcalix[8]areneH8 or p-tert-butylhexahomotrioxacalix[3]areneH3 led to the isolation of [HNEt3]2[H2NEt2]2{[VO(OMe)]2p-tert-butylcalix[8-SO2]areneH2} (4), [HNEt3]2[V(O)2p-tert-butylcalix[8]areneH5] (5) and [HNEt3]2[VIV2VV4O11(OMe)8] (6), respectively. Dc magnetic susceptibility measurements were performed on powdered microcrystalline samples of 1–3 in the T = 300–2 K temperature range. Preliminary screening for electrochemical water oxidation revealed some activity for 2 with turnover frequency (TOF) and number (TON) of 2.2 × 10−4 s−1 and 6.44 × 10−6 (mmol O2/mmol cat.), respectively. The compound 3 showed an improved electrochemical activity in the presence of water. This is related to the increased number and the rate of electrons exchanged during oxidation of V4+ species, facilitated by protons generated in the water discharge process. [ABSTRACT FROM AUTHOR]

The reaction of vanadyl sulfate, VOSO 4 ·H 2 O, with Schiff base ligand based on 2-hydroxybenzhydrazide and 5-bromosalicylaldehyde, with addition of 1,10-phenantroline as co-ligand, in ethanolic solution results in isolation of oxovanadium(IV) complex [VO(phen)L]·H 2 O (1). The complex was characterized by elemental analysis, single crystal X-ray structure measurements, IR, UV–Vis, EPR spectroscopy and cyclic voltammetry. Magnetic susceptibility measurements indicated the +4 vanadium oxidation state. The molecular structure of the complex was confirmed by single-crystal X-ray diffraction, revealing that the central vanadium atom was located in a six-coordinate distorted octahedral geometry. The stability of the complex at native pH and pH = 2.00 was also measured and the results are promising for application the vanadium complex as insulin mimetic compound. [ABSTRACT FROM AUTHOR]

This study examined the effects of vanadyl sulfate (VOSO4) on the livers of nondiabetic and streptozotocin-induced diabetic rats. Rats were divided into 6 groups. Groups 1, 2, and 3 consisted of nondiabetic rats that were, respectively, control animals or those receiving an intraperitoneal (i.p.) injection of either 5 or 10 mg·kg−1 (i.p.) VOSO4 for 30 days. Groups 4, 5, and 6 consisted of diabetic animals that were, respectively, control animals or those treated with 5 or 10 mg·kg−1 (i.p.) VOSO4 for 30 days. Results showed that VOSO4 reduced body mass in nondiabetic rats, whereas it increased body mass in diabetic groups. Plasma transaminases (aspartate aminotransferase, alanine aminotransferase), lactate dehydrogenase, and alkaline phosphatase activities and malondialdehyde levels were increased, while liver catalase and superoxide dismutase activities were profoundly decreased in diabetic animals in comparison with enzyme activities in the nondiabetic group. Rats in the diabetic group also showed notable oxidative damage to the liver. Treatment of diabetic rats with VOSO4 decreased the hepatotoxic markers, significantly restored the activities of antioxidant enzymes, and attenuated histopathological changes in liver tissue. In nondiabetic rats, VOSO4 treatment increased most of the hepatotoxic markers, reduced antioxidant enzyme activities, and induced pronounced oxidative damage in liver tissue. These data suggest that treatment with VOSO4 exerts toxic effects in healthy animals and significantly prevents liver oxidative damage in streptozotocin-induced diabetic rats, but without total safety. Further studies are needed to clarify its mechanism of action. [ABSTRACT FROM AUTHOR]

Background: Vanadium (V) is a candidate to decrease the serum level of glucose in diabetic animal model. However, it affects the lipid peroxidation and antioxidant activity so could make nephrotoxicity and hepatotoxicity. In this study, the protective role of vitamin C as an antioxidant on nephrotoxicity and hepatotoxicity induced by vanadyl sulfate was investigated. Methods: This study was designed in 2 protocols. There were 3 groups in protocol 1 that received saline (group 1), saline daily for 7 days plus single dose of vanadyl sulfate (50 mg/kg intraperitoneally) in day 2 (group 2), or vitamin C (250 mg/kg intraperitoneally) daily for 7 days and single dose of vanadyl sulfate (group 3). There were 2 groups in protocol 2 that received saline plus single dose of vanadyl sulfate (50 mg/kg intraperitoneally) in day 2 (group 4) or vitamin C (250 mg/kg intraperitoneally) daily for 2 days plus single dose of vanadyl sulfate (group 5). At the end of experiment, blood samples were collected to measure serum level of blood urea nitrogen (BUN), creatinine (Cr), aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP), and all animals were sacrificed for histopathology investigation and determination of kidney tissue damage score (KTDS). Findings: In protocol 1, BUN/Cr ratio, kidney weight (KW), and KTDS decreased significantly in vanadyl sulfate plus vitamin C group in comparison with vanadyl sulfate plus saline group (P < 0.05). In addition, serum level of AST and ALP significantly decreased in vanadyl sulfate plus vitamin C group. In protocol 2, not only similar results were not observed, but also vitamin C increased the side effects of vanadyl sulfate. Conclusion: Administration of vitamin C as a potent antioxidant could decrease the vanadium-induced toxicity. So, as vanadyl sulfate can be used for diabetic model in laboratory, vitamin C can be useful to decrease the vanadium-induced nephrotoxicity and hepatotoxicity, too.

The cyclic voltammetry technique was used to study the electrochemical behavior of vanadyl sulfate in absence and presence of antibiotic (cefazolin) in 0.1 M KCl under different pH values at 300.15 K. The redox behavior of vanadyl sulfate has been studied by using glassy carbon electrode, Ag/AgCl as a reference electrode and Pt wire as a counter electrode under potential from +1500 mV to −1000 mV. One anodic peak and one cathodic peak are observed in cyclic voltammograms. Peak current ratio and peak potential separation (ΔE) was calculated, the higher values of them gave an indication about systems under study are quasi-reversible. The effect of pH, scan rate and concentration of electroactive species on the interaction between vanadyl sulfate and antibiotic were studied. Charge transfer coefficients (α), the heterogeneous electron transfer rate constants (k s ) and the diffusion coefficients (D) involved in the redox reaction were evaluated. [ABSTRACT FROM AUTHOR]

2,5-Bis(aminomethyl)furan as a promising monomer was efficiently synthesized in 94.1% yield from biomass-derived 2,5-diformylfuran dioxime. The high selectivity is likely to be a result of the controlled reaction pathway over Rh/HZSM-5, which enhanced the sequence of the dehydration–hydrogenation of 2,5-diformylfuran dioxime owing to the surface acidity on the HZSM-5 support. [ABSTRACT FROM AUTHOR]

Coordination of vanadyl (VO2+) ions with 8-hydroxyquinoline (8Hq) in the interlayer space of layered silicate magadiite (mag) was realized by solid-solid intercalation. Composition, structure and morphology of this compound were studied by X-ray diffraction (XRD), Fourier-transform infrared spectrometry (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The obtained results indicate that the basal spacing of decorated mag increased after intercalation and suggest that VO-8Hq decorated into the interlayer of mag (VO-mag-8Hq) was successfully synthesized for the first time. Optical properties of VO-mag-8Hq were studied by ultraviolet-visible (UV-Vis) and photoluminescence spectroscopy (PL). The findings reveal that VO-8Hq complexes in the interlayer space exhibit extraordinary fluorescence properties and the confined space of mag influences the optical properties of VO-8Hq complexes. [ABSTRACT FROM AUTHOR]

Reactions of layered perovskite-like oxides K 2 La 2 Ti 3 O 10 , NaLaTiO 4 and corresponding protonated oxides H 2 La 2 Ti 3 O 10 , HLaTiO 4 with vanadyl sulfate aqueous solution have been studied. It was revealed that the exchange reaction of interlayer alkali cations in K 2 La 2 Ti 3 O 10 and NaLaTiO 4 by with vanadyl cations, which was reported in the literature previously, does not proceed. The formation of the corresponding protonated forms and vanadium-containing particles is found to occur instead. In the case of protonated forms H 2 La 2 Ti 3 O 10 , HLaTiO 4 vanadium-containing nanostructures are formed on the surface. [ABSTRACT FROM AUTHOR]

We have investigated electronic and catalytic modifications of the p-type semiconducting selective oxidation catalyst vanadyl pyrophosphate (VPP) for propane oxidation in the presence and absence of steam. Steam changes propane conversion only slightly, but increases the selectivity toward oxygenates (acrylic acid, acetic acid) and the olefin propylene resulting in reduced selectivity of the undesired total oxidation products CO and CO2. Contact-free in operando microwave conductivity measurements at 0.1 MPa revealed that the modified catalytic performance is accompanied by a reduced electrical conductivity. Surface sensitive near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS) and X-ray absorption spectroscopy (XAS) measurements at 25 Pa showed that steam depletes the topmost surface of VPP in phosphorus and enhances the average vanadium oxidation state slightly. These findings are accompanied by a decreased work function, but no detectable shift of the valence band edge is observed. Thus, the chemical surface modification changes the surface dipole but leaves the barrier height of the surface induced space charge layer basically unaffected. Hence, we conclude that steam does not affect the electron hole concentration (majority charge carriers) and hence the oxygen vacancy concentration. Therefore, the reduced conductivity can be understood in terms of charge carrier mobility changes, which may affect the selectivity of VPP toward oxygenates with steam. In addition, the modification of local properties, such as the concentration of acid sites as well as the nature and number of adsorption sites may have an impact on the catalytic properties. [ABSTRACT FROM AUTHOR]

VMCM-41 catalysts from two different tetravalent vanadium sources, hydrothermally synthesized after a mild gelation step at room temperature, were used as catalysts for the selective oxidation of methane to formaldehyde. Vanadyl acetylacetonate as VMCM-41 precursor, facilitates highest VO x density with predominance of monomeric and a small portion of low-oligomeric VO x species. It produces CH 2 O in high yield and the highest space time yield (STY CH2O ) reaches 5.3 kg CH2O ·kg cat − 1 ·h − 1 at 600 °C (rate of formation, r CH2O of 363 h − 1 ). VMCM-41 synthesized from vanadyl sulfate hydrate precursor contains a more significant portion of low-oligomeric species. With a lower V loading, these VO x species are significantly less active resulting in a maximum STY CH2O of 2.7 kg CH2O ·kg cat − 1 ·h − 1 at 625 °C (r CH2O of 243 h − 1 ). [ABSTRACT FROM AUTHOR]

A simple and expedient multicomponent protocol was developed to synthesize 4-thiazolidinones by employing VOSO 4 as a catalyst under ultrasonic irradiation. The significant features of this protocol includes shorter reaction time, high yields, low catalyst loading, and also the catalyst can be recovered and reused up to next four cycles without significant loss in catalytic activity. All the synthesized novel indazole compounds were evaluated for their antibacterial and anti-biofilm activities. Compounds 9n , 9o and 9q showed promising activity (MIC value of 3.9 µg/mL) against K. planticola (MTCC 530). They also exhibited significant bactericidal activity against K. planticola (MTCC 530) (MBC value of 15.6 µg/mL). Additionally, 9n , 9o and 9q inhibited biofilm formation (IC 50 values ranging between 20.28–20.79 μg/mL) in this organism. [ABSTRACT FROM AUTHOR]

Correlations are reported between structure and performance of current, state-of the art, industrial maleic anhydride production catalysts. Characterization was done with fully equilibrated catalysts to achieve reliable correlations of structure and activity. The kinetic analysis of the investigated VPO catalysts revealed differences in activities but comparable activation energies indicating active on-surface sites of similar nature but of different concentrations. One major crystalline component, VPP, and six minority compounds were identified, hence, VPP alone cannot be reasonably correlated with catalytic activity. XPS revealed elevated V concentrations, differences in the P/V ratios, and the P surface content correlates negatively with catalytic activity. Hence, all crystalline phases must have noncrystalline, surface-layers containing V species and varying P amounts. Deconvolution of Raman spectra identified four major vanadyl phosphate species of changing concentrations. One species, α-VOPO, was absent from the XRD patterns of the two most active catalysts, indicating that it is noncrystalline and, hence, integral part of the amorphous surface layers. These spectral/structural differences correlated with catalyst activity. The most active catalysts contain relatively more crystalline VPP, in accordance with literature. These active catalysts also have a higher amount of the amorphous V surface species, α-VOPO. All other V species detected, δ- and -VOPO are crystalline and negatively affect catalyst activity. Again in agreement with literature, the surface P/V ratio negatively correlates with catalyst activity, while the reported correlation of the V/V ratio with activity was not observed. The multi-method approach chosen here, always strongly favored by H. Knözinger, generated a detailed picture of the compositional differences between the bulk and surface regions of the investigated catalysts and revealed how these differences correlate with catalytic performance. [ABSTRACT FROM AUTHOR]

Periodic electrochemical oscillation of the anolyte was reported for the first time in a simulated charging process of the vanadium redox flow batteries. The electrochemical oscillation could be explained in terms of the competition between the growth and the chemical dissolution of V2O5 film. Also, the oscillation phenomenon was possible to regular extra power consumption. The results of this paper might enable new methods to improve the charge efficiency and energy saving for vanadium redox flow batteries.

The reaction between vanadyl sulfate and an NNO donor Schiff base (HL 1 or HL 2 ) in methanol resulted in the formation of two new binuclear vanadium(V) complexes, viz., [(L 1 )VO(μ-O) 2 VO(L 1 )]0.5H 2 O ( 1 ) and [(L 2 )VO(μ-O) 2 VO(L 2 )] ( 2 ) (L 1 = N ′-[( E )-phenyl(pyridin-2-yl)methylidene]benzohydrazide and L 2 = N ′-[( E )-phenyl(pyridin-2-yl)methylidene]furan-2-carbohydrazide). During the reaction, atmospheric oxygen spontaneously acted as an oxidizing agent and yielded new (V IV → V V ) vanadium(V) complexes. The electronic spectra of 1 and 2 shown the vanadium(V) centre is in a distorted octahedral environment in each case. The complexes were characterized by routine physico-chemical methods. The single crystal X-ray structures of 1 and 2 also revealed a distorted octahedral coordination around each of the vanadium(V) centres, confirming the NNO binding mode of the ligands L 1 and L 2 . In these binuclear complexes, the bridging functions are the μ-oxido bonds. The occurrence of weak CH⋯π interactions in 1 and π⋯π stacking interactions in 2 contribute extra stabilization in their solid state. The complexes catalyzed the dismutation of superoxide in an alkaline nitroblue tetrazolium chloride assay and the IC 50 values were estimated. [ABSTRACT FROM AUTHOR]

Using the atomic absorption spectrometry and electronic paramagnetic resonance techniques, we have investigated the features of vanadium and vanadyl complexes content in asphaltenes of heavy oils of Permian and Carboniferous productive sediments in the Volga-Ural oil and gas basin deposits. The investigation has been carried out using the heavy oils example, where the asphaltene content ranges from 5.1 to 21.2 wt%, and vanadium content varies in the range of 0.009–0.165 wt%. The specificity of asphaltene–vanadium relationship has been found for heavy oils of various productive sediments. It has been demonstrated that vanadium and vanadyl complexes content in asphaltenes of heavy oils in separate productive sediments varies in the certain range limits. [ABSTRACT FROM PUBLISHER]