Fast Microwave-Assisted Synthesis of Wells-Dawson-Type 18-Tungsto-2-Phosphate [P₂W₁₈O₆₂]⁶⁻

We report on a fast microwave-assisted synthetic procedure of the Wells-Dawson-type 18-tungsto-2-phosphate [P2W18O62]6− with a 35% yield in 24 h, rather than a week using conventional heating

Polyoxometalates in Biomedicine: Update and Overview

Background: Polyoxometalates (POMs) are negatively charged metal-oxo clusters of early transition metal ions in high oxidation states (e.g., WVI, MoVI, VV). POMs are of interest in the fields of catalysis, electronics, magnetic materials and nanotechnology. Moreover, POMs were shown to exhibit biological activities in vitro and in vivo, such as antitumor, antimicrobial, and antidiabetic. Methods: The literature search for this peer-reviewed article was performed using PubMed and Scopus databases with the help of appropriate keywords. Results: This review gives a comprehensive overview of recent studies regarding biological activities of polyoxometalates, and their biomedical applications as promising anti-viral, anti-bacterial, anti-tumor, and anti-diabetic agents. Additionally, their putative mechanisms of action and molecular targets are particularly considered. Conclusion: Although a wide range of biological activities of Polyoxometalates (POMs) has been reported, they are to the best of our knowledge not close to a clinical trial or a final application in the treatment of diabetes or infectious and malignant diseases. Accordingly, further studies should be directed towards determining the mechanism of POM biological actions, which would enable fine-tuning at the molecular level, and consequently efficient action towards biological targets and as low toxicity as possible. Furthermore, biomedical studies should be performed on solution-stable POMs employing physiological conditions and concentrations

Toxicity evaluation of two biologically active polyoxotungstates

Introduction. Polyoxometalates (POMs) are negatively charged inorganic aggregates that possess potential antibacterial, anticancer, antidiabetic and antiviral effects. Although toxicity evaluation of drug candidates is necessary, reports of relevant toxicological studies of these compounds are relatively rare. Aims. Since our preliminary results demonstrated biological activities of the donut-shaped POM {NaP5W30} (POM1) and the Ag + -containing derivative POM {AgP5W30} (POM2), the aim of present study was to evaluate their toxicological effects in vivo, using Wistar albino rats as an experimental model. Methods. Animals (n = 6 per group) were orally treated with investigated POMs in daily doses of 20 mg/kg body weight for 14 days when the rats were sacrificed and blood samples were collected. The biochemical markers of renal (serum concentrations of urea - SUr and creatinine - SCr) and liver function (serum concentrations of total protein–TP and albumin - Alb, serum activities of aspartate aminotransferase - AST and alanine transaminase - ALT) were determined spectrophotometrically. Results. The POM1 and POM2 were induced statistically significant increasing of SUr (in: mmol/L) (7.95 ± 0.35 and 6.83 ± 0.26 vs. 4.97 ± 0.47; p 0.05). Conclusion. Obtained results suggested that both investigated POMs induce kidney injury as well as synthetic dysfunction of liver. Thus, their potential clinical application would require a more complex toxicological study.Abstracts of the 8th International Congress of Pathophysiolog

15-Copper(ii)-containing 36-tungsto-4-silicates(iv) [Cu15O2(OH)(10)X(A--SiW9O34)(4)](25-) (X = Cl, Br): synthesis, structure, magnetic properties, and electrocatalytic CO2 reduction

The 15-copper(ii)-containing 36-tungsto-4-silicates [Cu15O2(OH)(10)X(A--SiW9O34)(4)](25-) (X = Cl, 1; Br, 2) have been prepared in 70% yield by reaction of the trilacunary 9-tungstosilicate precursor [A--SiW9O34](10-) with Cu2+ ions in aqueous pH 8 medium. Both polyanions 1 and 2 were isolated as hydrated mixed potassium/sodium salts and characterized in the solid state by FT-IR, TGA, single-crystal XRD, and elemental analysis. DC magnetic susceptibility measurements from 1.8-300 K established the ground state to be paramagnetic with a magnetic moment corresponding to 15 uncoupled Cu2+ (S = 1/2) ions. EPR measurements and simulations were consistent with this analysis. Electrochemical studies were performed for polyanions 1 and 2 dissolved in solution to elucidate the electroactivity of both copper and tungstate sites. Using 2 as a representative example, the electrocatalytic activity towards CO2 reduction upon deposition on a glassy carbon electrode surface, while retaining selectivity relative to hydrogen evolution, was demonstrated.</p

Toxicity evaluation of two polyoxotungstates with anti-acetylcholinesterase activity

A toxicity evaluation of two Keggin-type heteropolytungstates, K-7[Ti2PW10O40].6H(2)O and K6H [SiV3W9O40].3H(2)O, with different inhibitory potencies toward acetylcholinesterase activity (IC50 values of 1.04 x 10(-6) and 4.80 x 10(-4) mol/L, respectively) was performed. Wistar albino rats were orally treated with single doses (5 and 50 mg/kg) of both investigated compounds. The biochemical parameters of renal (serum urea and creatinine) and liver function (direct and total bilirubin, alanine transaminase, and aspartate aminotransferase) were determined after 24 h and 14 days. A histopathological analysis of liver tissue was carried out 14 days after the polyoxotungstate administration. Both applied doses of the investigated compounds did not induce statistically significant alterations of the renal function markers. However, the polyoxotungstate treatment caused an increase in the activities of serum alanine transaminase and aspartate aminotransferase in a time- and concentration -dependent manner, although statistically significant changes in bilirubin concentrations were not observed. Furthermore, the detected hepatotoxic effect was confirmed by histhopathological analysis that suggested some reversible liver tissue damage two weeks after the treatment, especially in the case of K6H [SiV3W9O40]-3H(2)O. Accordingly, the toxicity of these two polyoxotungstates with anti-acetylcholinesterase effect cannot be considered as a severe one, but their potential clinical application would require a more complex toxicological study

In vivo toxicity evaluation of two polyoxotungstates with potential antidiabetic activity using Wistar rats as a model system

In this study, thein vivohypoglycemic effect of a donut-shaped polyanion salt (NH4)14[Na@P5W30O110]$31H2O{NaP5W30} and its Ag-containing derivative K14[Ag@P5W30O110]$22H2O$6KCl {AgP5W30}, as wellas their hepatotoxicity and nephrotoxicity, was evaluated. In the screening hypoglycemic study,Wistaralbinorats with streptozotocin induced diabetes were treated intraperitoneally with three single doses (5,10, and 20 mg per kg per b.w.) of both investigated polyoxotungstates. The blood glucose levels,measured before and after 2, 4 and 6 h polyoxotungstate application, showed that both studiedcompounds induced the most pronounced and time dependent glucose lowering effects at the doses of20 mg kg1. Thus, daily doses of 20 mg kg1were administered toWistar albinorats orally for 14 days infurther toxicity examinations. The serum glucose concentration and biochemical parameters of kidneyand liver function, as well as a histopathological analysis of kidney and liver tissues were evaluated 14days after the polyoxotungstate administration. Both investigated compounds did not induce statisticallysignificant alterations of the serum glucose and uric acid concentrations, as well as some of the liverfunction markers (serum alanine and aspartate aminotransferases, and alkaline phosphatase activities).However, the significant decrease in serum total protein and albumin concentrations and the increase inbiochemical parameters of renal function–serum urea (up to 63.1%) and creatinine concentrations (upto 23.3%) were observed for both polyoxotungstates. In addition, the detected biochemical changeswere in accordance with kidney and liver histhopathological analysis. Accordingly, the hepatotoxic andnephrotoxic effects of these potential antidiabetic polyoxotungstates could be considered as mild

Dithallium(III)-Containing 30-Tungsto-4-phosphate, [Tl2Na2(H2O)2(P2W15O56)2]16-: Synthesis, Structural Characterization, and Biological Studies

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Dithallium(III)-Containing 30-Tungsto-4-phosphate, [Tl Na (H O) (P W O ) ] : Synthesis, Structural Characterization, and Biological Studies

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Dithallium(III)-Containing 30-Tungsto-4-phosphate, [Tl₂Na₂(H₂O)₂(P₂W₁₅O₅₆)₂]^16–: Synthesis, Structural Characterization, and Biological Studies

Here we report on the synthesis and structural characterization of the dithallium­(III)-containing 30-tungsto<i>-</i>4-phosphate [Tl₂Na₂(H₂O)₂­{P₂W₁₅O₅₆}₂]^16– (<b>1</b>) by a multitude of solid-state and solution techniques. Polyanion <b>1</b> comprises two octahedrally coordinated Tl³⁺ ions sandwiched between two trilacunary {P₂W₁₅} Wells–Dawson fragments and represents only the second structurally characterized, discrete thallium-containing polyoxometalate to date. The two outer positions of the central rhombus are occupied by sodium ions. The title polyanion is solution-stable as shown by ³¹P and ^203/205Tl NMR. This was also supported by Tl NMR spectra simulations including several spin systems of isotopologues with half-spin nuclei (²⁰³Tl, ²⁰⁵Tl, ³¹P, ¹⁸³W). ²³Na NMR showed a time-averaged signal of the Na⁺ counter cations and the structurally bonded Na⁺ ions. ^203/205Tl NMR spectra also showed a minor signal tentatively attributed to the trithallium-containing derivative [Tl₃Na­(H₂O)₂­(P₂W₁₅O₅₆)₂]^14–, which could also be identified in the solid state by single-crystal X-ray diffraction. The bioactivity of polyanion <b>1</b> was also tested against bacteria and <i>Leishmania</i>