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In this work, Preyssler‐type POM (NH4)14[NaP5W30O110].44H2O (NH4P5W30), has been synthesised and its electrochemical behaviour in solution was examined at the surface of glassy carbon (GC) and gold electrodes. Furthermore, multilayer assemblies of NH4P5W30 POM were constructed onto the surfaces of GCE, gold electrode, and gold quartz electrode via the electrostatic Layer‐by‐Layer (LBL) technique employing polyethyleneimine as the cationic layer and POM as an anionic layer. Cyclic voltammetry, electrochemical impedance spectroscopy (EIS), and electrochemical quartz crystal microbalance measurements (EQCM) were used to monitor the LBL assembly as the NH4P5W30 POM layer was being built. These techniques revealed significant differences in film growth. The multilayer film exhibited well‐defined redox couples associated with POM's tungsten‐oxo framework and showed surface‐confined behaviour up to 100 mVs−1 on both the GC and gold electrodes. The pH dependency and stability of the film were investigated. EIS demonstrated that when the POM layer was the outer layer, the layers were less conductive, and resistance increased as the number of layers increased. In addition, the charge transfer resistance values (Rct) for the layers were calculated. The solvation of ions into the film associated with POM redox activity was studied employing an in‐situ EQCM. [ABSTRACT FROM AUTHOR]

Propagating micro-cracks in a structure decreases its load-bearing capacity and leads to the collapse of the entire structure. Addition of various additives in all kinds of concrete or concrete ingredients, as several studies have shown, could significantly make concrete reclaim from the specifications and attributes point of view. A possible manner to the common ruin and expensive preservation of concrete infrastructure, utilizing encapsulating healing factors is helpful for the self-healing of concrete. The selfhealing concrete with microencapsulated Preyssler, and calcium nitrate was studied in this paper. Microcapsules were synthesized by in-situ polymerization of urea-formaldehyde as a shell around the core materials inclusive of Preyssler, calcium nitrate. Physicochemical characterization of microcapsules was conducted by Fourier transformation infrared spectroscopy, field emission scanning electron microscopy, and Transmission Electron Microscope. The mechanical assessment of cementitious specimens with different dosages of microcapsules (0%,0.5%, 1%, 1.5%, and 2%) was performed by compressive tests. Also, by measurement before and after damage after 10 days, the self-healing potential was tested. After the concrete was damaged by exerting 30% of its final load, all samples were incubated by immersion in water. According to the results, the sample containing 0.5% UFN, the sample containing 1.5% UFP, and the sample containing 1.5% UFNP have higher repair rates than others. This scope of research because of its interdisciplinary nature would own several possibilities to be pioneering with making an opening gate to link sciences and engineering such as material, chemistry, science, nanotechnology, and the field of engineering to persuade a wide spectrum of contribution in engineering sciences and usages. [ABSTRACT FROM AUTHOR]

Abstract In this work, Preyssler‐type POM (NH4)14[NaP5W30O110].44H2O (NH4P5W30), has been synthesised and its electrochemical behaviour in solution was examined at the surface of glassy carbon (GC) and gold electrodes. Furthermore, multilayer assemblies of NH4P5W30 POM were constructed onto the surfaces of GCE, gold electrode, and gold quartz electrode via the electrostatic Layer‐by‐Layer (LBL) technique employing polyethyleneimine as the cationic layer and POM as an anionic layer. Cyclic voltammetry, electrochemical impedance spectroscopy (EIS), and electrochemical quartz crystal microbalance measurements (EQCM) were used to monitor the LBL assembly as the NH4P5W30 POM layer was being built. These techniques revealed significant differences in film growth. The multilayer film exhibited well‐defined redox couples associated with POM's tungsten‐oxo framework and showed surface‐confined behaviour up to 100 mVs−1 on both the GC and gold electrodes. The pH dependency and stability of the film were investigated. EIS demonstrated that when the POM layer was the outer layer, the layers were less conductive, and resistance increased as the number of layers increased. In addition, the charge transfer resistance values (Rct) for the layers were calculated. The solvation of ions into the film associated with POM redox activity was studied employing an in‐situ EQCM.

In the present study, platinum nanoparticles were synthesized through an effective, facile and green method using H14[NaP5W30O110], a Preyssler-structured polyoxometalate, under UV light irradiation. Preyssler plays the roles of photocatalyst, reducing agent and stabilizer in the synthesis of Pt nanoparticles. The effect of different parameters, i.e. time, propan-2-ol volume, pH, molar ratio of Preyssler to Pt ions ([Preyssler]/[Pt4+]) and temperature on the size of prepared nanoparticles were investigated. Under different conditions, platinum nanoparticles with minimum size of 13 nm were ultimately obtained. The nanoparticles were characterized by UV/Vis spectroscopy, particle size distribution, transmission electron microscopy and electron diffraction techniques. The results showed that the photocatalytic behavior of Preyssler was a propulsion factor in reducing the Pt4+ ions. The resultant NPs are covered with a Preyssler layer which contributes to the stabilization of NPs. It was shown that the subsequent increasing of NP size can be on account of partly increasing rate of NP growth compared to nucleation. Moreover, the stability of obtained nanoparticles was inspected.

Among different biopolymers, cellulose being the first abundant biopolymers in nature has many fascinating properties, including low cost, good biodegradability, and excellent biocompatibility, which made cellulose a real potential material to create nano-drug delivery systems. Regarding, emphasis of science and technology shifts toward environmentally friendly and sustainable resources and processes, herein, we report a facile, one pot and green synthesis of the catenated assemblies of cellulose nanoparticles (CNPs) via acidic catalysis in the presence of preyssler heteropolyacid. This fast, green, and high-yield catalytic synthesis reduces the time of reaction to 15 min using low-intensity ultrasonic waves of 150 W. CNPs were characterized by transmission electron microscopy, scanning electron microscopy, particle size distribution analysis, Fourier-transformed infrared spectroscopy, X-ray diffraction, and atomic force microscopy. The results showed that catenated CNPs exhibit spherical-like structures with widths and lengths of 35–40 and 50–150 nm, respectively. The CNPs showed a surface charge of −35.2 mV, which allows obtaining a stable colloidal suspension. Moreover, cellulose nanoparticles loaded with ascorbic acid (CNPs/AA) were engineered and ascorbic acid could be released from the CNPs/AA in a controlled manner for 1 h. [ABSTRACT FROM AUTHOR]

For the first time, sodium 30-tungstopentaphosphate, a green and efficient solid acid, was used for the isolation of cellulose from rice husk, resulting in the generation of Preyssler heteropolyacid-cellulose acetate hybrid nanofibers. These modified fibres were characterised by Fourier transform infrared spectroscopy spectrum, scanning electron microscopic images and energy-dispersive spectrometry. It was also showed that Preyssler heteropolyacid was evenly dispersed on or into the nanofibers and the distribution became denser as the concentration of Preyssler HPA increased. The electrospuned nanofibers were employed successfully for the photodegradation of methyl orange, a common azo dye pollutant in the environment.

Keggin, Wells-Dawson and Preyssler structured polyoxometalates (POMs) were synthesized by different methodologies. The POMs were used as catalysts for ammoxidation of 2-methylpyrazine. The structural properties of POMs were determined by XRD, SEM, DRIFT, DRUV- vis , H 2 -TPR, NH 3 -TPD and N 2 -physisorption. Preyssler POM sample showed highest 2-methylpyrazine conversion (69%) and 2-cyanopyrazine selectivity (98%) at 380 °C. Superior performance of Preyssler POM could be attributed to its redox behavior and relatively strong acid sites. Large number of ammonium ions in the secondary structure of Preyssler POM could also enhance the transformation of oxygenated 2-methylpyrazine species into 2-cyanopyrazine. A correlation between the amount of ammonium content of POMs and their catalytic ammoxidation activity was obtained. [ABSTRACT FROM AUTHOR]

For the first time, sodium 30-tungstopentaphosphate, a green and efficient solid acid, was used for the isolation of cellulose from rice husk, resulting in the generation of Preyssler heteropolyacid-cellulose acetate hybrid nanofibers. These modified fibres were characterised by Fourier transform infrared spectroscopy spectrum, scanning electron microscopic images and energy-dispersive spectrometry. It was also showed that Preyssler heteropolyacid was evenly dispersed on or into the nanofibers and the distribution became denser as the concentration of Preyssler HPA increased. The electrospuned nanofibers were employed successfully for the photodegradation of methyl orange, a common azo dye pollutant in the environment. [ABSTRACT FROM AUTHOR]

The catalytic oxidation of thiols to the corresponding disulfides usingPreyssler’s catalyst H14[NaP5W30O110] has been studied. These highly selective oxidationsgave good yields of the target disulfides.

BACKGROUND This study concerns the application of magnetic heteropolyacids composite for the adsorption of organic compounds from aqueous solutions. A novel magnetic Preyssler/chitosan/Fe3O4 nanoparticles composite (PCNF) adsorbent was designed using a one-pot synthesis method and characterized by multiple techniques including X-ray powder diffraction (XRD), infrared spectroscopy (FT-IR), N2 adsorption-desorption isotherms and scanning electron microscopy (SEM). RESULTS The adsorption activity of PCNF was evaluated by the removal of methyl orange (as an anionic azo dye model, MO) from aqueous solution and all the factors influencing the removal efficiency, such as adsorbent dosage, initial dye concentration, and initial pH have been studied. Results show that the Langmuir adsorption and pseudo-first-order rate equations can well describe the adsorption of MO onto the PCNF surface. The maximum MO adsorption capacity for the PCNF was estimated to be 88.5 mg g−1 at 45°C. CONCLUSIONS The adsorption kinetic data of MO on PCNF are generally well described by the pseudo-first-order model, and it is shown that pore diffusion seems to be the limiting factor for the adsorption kinetics. The MO adsorption capacity obtained was higher than capacities found in the literature for various other adsorbents. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

A novel nanomagnetic organic–inorganic hybrid catalyst (Fe@Si-Gu-Prs) was prepared by the chemical anchoring of Preyssler heteropolyacid (H 14 [NaP 5 W 30 O 110 ]) onto the surface of modified Fe 3 O 4 magnetic nanoparticles with guanidine-propyl-trimethoxysilane linker. The synthesized magnetically green catalyst has been characterized with several methods (FTIR, SEM, TEM, EDS, VSM, TGA-DTG, XRD, BET, and ICP) and these techniques confirmed that the Preyssler heteropolyacid is well dispersed on the surface of the solid support and its structure is retained after immobilization on the modified silica-coated Fe 3 O 4 nanoparticles, also the content of W in catalyst was measured by inductively coupled plasma optical emission spectroscopy (ICP-OES). After full characterization, its catalytic activity investigated in the synthesis of tetrahydropyridine derivatives at room temperature under solvent-free conditions. This nano hybrid catalyst can carry out the reactions in lower than 45 min with excellent yields, and the catalyst is easily isolated from the reaction mixture by an external magnet and reused at least five times without significant loss of activity. [ABSTRACT FROM AUTHOR]

In this study, we introduced a novel nanocomposite consisting of Au nanoparticles decorated TiO2 and Preyssler acid as a multifunctional photocatalyst linker molecule, in which gold ions reduced locally on the TiO2 surface. The obtained nanocomposite has been characterized using Fourier Transform Infrared (FTIR), X-ray Diffraction (XRD), Electron Dispersive X-ray (EDX) Spectroscopy, Transmission Electron Microscopy (TEM) and Scanning Electron Microscope (SEM). Also, their photocatalytic activity has been studied for the degradation of model organic azo dye Malachite Green under UV light irradiation. [ABSTRACT FROM AUTHOR]

Liquid-phase alkylation of benzene with 1-decene for the production of linear alkylbenzene (LAB) was investigated with silica-supported Preyssler heteropoly acid as the catalyst. Catalyst loading, Bz/C10molar ratio, and catalyst weight percentage were investigated. Catalyst with 30% loading, Bz/C10molar ratio of 17, and catalyst weight percentage of 2.6 showed 1-decene conversion of 100% and 2-phenyl decane selectivity of 27.2% at 80°C and 2-hr reaction. [ABSTRACT FROM AUTHOR]

An efficient and convenient method for the synthesis of 1,4-dihydropyridines from β-dicarbonyl compounds, aldehydes, and ammonium acetate and the synthesis of fused 1,4-dihydropyridines from dimedone in the presence of Preyssler heteropolyacid catalyst are reported under reflux conditions with good to excellent yields. Preyssler heteropolyacid catalyst is easily prepared, stable (up to 300 °C), reusable, efficient, green and inexpensive. [ABSTRACT FROM AUTHOR]

The authors describe a facile procedure for size-controlled synthesis of gold nanoparticles based on the reduction of Au3+ (HAuCl4) using Preyssler heteropolyacid (H14[NaP5W30O110]) under UV irradiation. Preyssler plays the role of green reducing agent and also efficient stabilizer. This method allows the synthesis of uniform hexagonal nanoparticles with an average size that is tunable between 1.35 and 86.7 nm by varying the gold ion concentration, molar ratio of gold ion to Preyssler, and Propan-2-ol amount. The authors found that there is a critical ratio for [Au3+]/[Preyssler] in which two opposing trends in the size of nanoparticles would happened. [ABSTRACT FROM AUTHOR]

Two novel chiral organic-inorganic hybrid materials based on two important heteropolyoxometallate namely Preyssler and Wells-Dawson anions, (Hval)(Hgly)(HO)K[Na(HO)PWO]·19.5HO ( 1) and (Hpro)[PWO]·8HO ( 2), were prepared and characterized by elemental analysis, X-ray diffraction, and infrared spectroscopy. The mixed amino acid as cations, Preyssler and Wells-Dawson as anions held together into a 3D-network through hydrogen-bonding interactions. The most unique structural features of 1 and 2 are their 3D-inorganic infinite tunnel-like framework. It results a weak van der Waals interlayer interaction. This provides a desirable condition to use its potential as a host in a host-guest complex. The chirallity for these two crystal structures, with the space group P2 has been observed. The electrostatic forces and hydrogen bonding, keep these ''adducts'' stable in the solid state. [ABSTRACT FROM AUTHOR]

Preparation of gold nanoparticles by chemical reduction method using Preyssler heteropolyacid was investigated. The experimental conditions have been optimized using Taguchi robust design method with L9 orthogonal array. Particle size of the gold nanoparticles was considered as the property in the optimization. Amounts of Preyssler heteropolyacid, pH and irradiation time were selected as the main parameters. The result of Taguchi analysis has shown that in this process, the preyssler acid amount is the most influencing parameter on the size of gold nanoparticle. Also, the effects of different parameters are in order to: Preyssler acid amount > pH > irradiation time (negligible). This method showed that decreasing Preyssler amount and increasing pH of solution lead to formation of smaller nanoparticles. Finally, the prepared nanoparticles at optimum condition with a size of about 6.42 were characterized by using Dynamic Light Scattering (DLS) method, transmission electron microscopy (TEM), and UV-Vis spectroscopy. [ABSTRACT FROM AUTHOR]

An efficient, improved, and environmentally benign procedure for catalytic oxidation of benzyl alcohols to the corresponding benzaldehdes was developed in the presence of nano-SiO2-supported Preyssler heteropolyacid (HPA), both in thermal conditions and under microwave irradiation. Silica nanostructures were obtained through a sol–gel method and were characterized by transmission electron microscopy and powder x-ray diffraction. Nano-SiO2-supported Preyssler HPA was synthesized by an impregnation method and confirmed by infrared spectroscopy. In catalytic reactions, the effects of various parameters such as catalyst loading, catalyst amount, temperature, and reaction time were studied and the optimum conditions were obtained. [ABSTRACT FROM PUBLISHER]

Abstract: K6P2W18O62 and K14[NaP5W30O110] polyoxometalate salts are synthesized and immobilized within MCM-48, SBA-3, SBA-15 and NH3 + functionalized mesoporous silicas. The newly designed hybrid materials are studied as catalysts for oxidation of thioethers. Preyssler complex is found to be a more active catalyst compared to its Dawson analog. Texture and chemical composition of the silica framework is shown to have indispensable effect on oxidation efficiency, stability, and reusability of catalysts. Catalysts with larger pores are proved to be more proper for the oxidation of relatively large thioethers and functionalization improves catalyst''s properties. [Copyright &y& Elsevier]

A novel and simple approach is reported to fabricate ZnO nanorods in the presence of nano Preyssler polyoxometalate. The morphology and size of these nanorods were characterized using transmission electron microscopy and X-ray diffraction. The performance of nano form of Preyssler was compared with bulk form. Results showed that both Preyssler and nano Preyssler produce ZnO nanorods via a solvothermal route. In a designed photo reactor, the photocatalytic degradation of methyl orange as common azo dye pollutants was selected as a test reaction to estimate the catalytic activity of the synthesized ZnO nanorods and found to be excellent. [ABSTRACT FROM AUTHOR]

Photocatalytic oxidation of aromatic aldehydes to related carboxylic acids was investigated with molecular oxygen in the presence of Preyssler anion, with formula [NaP5W30O110]14 -. It was observed that H14[NaP5W30O110] could catalyze the oxidation of aromatic aldehydes by molecular oxygen under homogeneous conditions as well as supported on silica in heterogeneous conditions. Also, for further studies, we have investigated the application of Preyssler catalyst in the presence of hydrogen peroxide as oxidizing agent. Our findings showed that this catalyst is very active in the presence of hydrogen peroxide and UV light. The effects of catalyst concentration, time and loading percentage have been studied. [ABSTRACT FROM AUTHOR]

Preyssler acid as bulk form, H14[NaP5W30O110] and silica-supported with different loadings used as green, eco-friendly and recyclable photocatalysts for catalytic oxidation of benzyl alcohols to the corresponding aldehyds under O2 and H2O2. High selectivity and moderate to excellent yields were obtained. Silica-supported Preyssler were less active than the bulk form under the same conditions. Our findings showed that the catalyst concentration, time, loading percentage, and amount of the catalyst are important factors. [ABSTRACT FROM AUTHOR]

Heteropolyacid (H14 [NaP5W30O110])/SiO2 nano particles were synthesized by a micro emulsion technique. The morphology and size of these nano particles were characterized using, transmission electron microscopy and X-ray diffraction. In a designed photo reactor, the photo degradation of methyl orange as common azo dye pollutants in the environment was selected as a test reaction to estimate the catalytic activity of the synthesized nano particles and found to be excellent. [ABSTRACT FROM AUTHOR]

Using, Preyssler acid, H14[NaP5W30O110], as the reaction promoter, the synthesis of silver nanoparticles by chemical reduction of silver nitrate was carried out in water as an environmentally safe solvent. Poly(N-vinyl-2-pyrolidone) (PVP) was used as stabilizer, which can be readily washed out at the end of reaction. Metal nanoparticles were characterized by transmission electron microscopy (TEM), x-ray diffraction (XRD), and ultraviolet-visible (UV-Vis) spectroscopy. The catalytic performance of silver nanoparticles (Ag NPs) for photodegradation of the azo dyes methylene blue (MEB) and methyl orange (MeO) has been investigated in aqueous solution. UV-Vis studies showed that Ag NPs can catalyze photodegradation of these azo dyes. The pseudo-first-order rate constants were calculated. [ABSTRACT FROM AUTHOR]

The Keggin and Preyssler-structured tungstophosphoric acid catalysts anchored on the surface of modified SBA-15 (KNS and PNS) by grafting amine groups into system, and were characterized by infra-red spectroscopy, X-ray diffraction, N2-adsorption, Hammett indicator and UV-Vis spectroscopy. Their catalytic behaviors were investigated in the esterification of n-butanol with acetic acid. Characterization results for obtained catalysts verified the ordered hexagonal mesostructure of SBA-15 and preservation of the structures of heteropolyanions on amine-modified SBA-15. KNS and PNS catalysts with the 37 and 25% loadings of Keggin and Preyssler acids exhibited considerable conversions of n-butanol of 61.2 and 63.8% with both 100% selectivity for n-butyl acetate in the esterification reaction, respectively. Especially, tests of six-cycle reaction revealed good reusabilities of KNS and PNS due to their excellent water-resistance properties, and in contrast, the catalysts prepared by direct impregnation lost their high activities immediately at their second cycles. Active sites on the amine-modified SBA-15 retained the Keggin or Preyssler structure after reaction demonstrated by IR analysis. Also, reaction conditions such as the amount of catalyst, reaction time and temperature were explored. [ABSTRACT FROM AUTHOR]

Abstract: Under mild conditions a liquid phase alkylation of phenol with 1-octene was studied in the presence of Preyssler catalyst, H14[NaP5W30O110]. This polyanion with high hydrolytic stability (pH 0–12), thermal stability and high acidic strength shows great activity. The effects of various parameters on the yield of product, including catalyst type, reactant molar ratio, solvent type and reaction time were studied. Comparison between Keggin type heteropolyacids, H5[PMo10V2O40], H6[PMo9V3O40] and Wells–Dawson, H6[P2W18O62] with Preyssler’s anion shows that the latter reacts better than the other studied heteropolyacids and without any degradation of the structure. [Copyright &y& Elsevier]

Abstract: A simple, clean and environmentally benign route to the synthesis of 2-amino-4H-chromenes is described using Preyssler type heteropolyacid, H14[NaP5W30O110], as a green and reusable catalyst in water. The products were obtained in very good yields. [Copyright &y& Elsevier]

Abstract: Direct esterification of butanol to butylbutanoate in the absence of butanoic acid has been investigated by a series of green solid acid catalysts, including H14[NaP5W30O110], H 14 -P 5 , H14[NaP5W29MoO110], H 14 -P 5 Mo and silica supported H14[NaP5W30O110], H 14 -P 5 /SiO 2 , with H2O2 as oxidizing agent at reflux and at room temperatures. The performance of these eco-friendly catalysts were compared with H2SO4. Maximum butylbutanoate yield and product selectivity (100%) was observed by using H 14 -P 5 Mo as the catalyst. The effects of various parameters such as catalyst type, reaction times, reaction temperatures, and molar ratio of n-butanol to hydrogen peroxide have been studied. The green catalysts can be easily recovered and recycled with retention of their initial structure and activity. [Copyright &y& Elsevier]

Abstract: Benzylic, allylic and aliphatic alcohols were transformed into the corresponding carbonyl compounds by catalytic oxidation of preyssler type heteropolyacid supported onto silica gel, H14[NaP5W30O110]/SiO2, in a heterogeneous system. The catalyst can be recovered and reused. [Copyright &y& Elsevier]

Abstract: 2,3-Dihydro-1H-1,5-benzodiazepines are synthesized by the condensation of o-phenylenediamine and various ketones in the presence of Preyssler heteropolyacid as a recyclable catalyst in refluxing ethanol. [Copyright &y& Elsevier]

Abstract: Catalytic performance of Preyssler, H14[NaP5W30O110], and Keggin, H3[PW12O40], heteropolyacids as pure and supported on silica, H14[NaP5W30O110]/SiO2, H3[PW12O40]/SiO2, have been studied in cyclocondensation of 4-amino-3-hydrazino-6-methyl-1,2,4-triazin-5(2H)-one (4-AHMT) with orthoesters. The catalytic activity of various forms of these catalysts in different solvents was compared with other classical catalysts, such as H2SO4 and HY-zeolite. In all cases the best yields were obtained, using H14[NaP5W30O110]. [Copyright &y& Elsevier]

Abstract: Many substituted anilines were converted into the corresponding azoxy benzenes as major products, by hydrogen peroxide, using Preyssler catalyst. The ability of various Preyssler catalysts as pure, H14[NaP5W30O110], mixed addenda, H14[NaP5W29MoO110], and cetylpyridinium acidic salt, was investigated. In all cases, the highest yield of azoxy compounds was observed, using H14[NaP5W30O110] as catalyst. The oxidations of anilines with 30% H2O2 catalyzed by Preyssler catalysts in various solvents with different molar ratio of amine to oxidant, have been investigated and the results showed that the reaction yields were affected by changing the solvent as well as molar ratio of amine:oxidant. [Copyright &y& Elsevier]

Abstract: γ-Butyrolactone, ɛ-caprolactone and 2-cumaranone are synthesized from related diols, using Preyssler heteropolyacids, H14[NaP5W30O110] and H14[NaP5W29MoO110] as catalyst, and hydrogen peroxide as oxidizing agent. The performance of eco-friendly Preyssler catalysts was compared with H2SO4 and the catalytic activity of H2SO4 is found to be lower than Preyssler catalysts. The effects of various parameters such as amount of diol, temperature, solvent and time were studied. In all cases, the Preyssler catalyst was easily recovered and recycled with retention of their initial structure and activity. [Copyright &y& Elsevier]

Abstract: A series of eco-friendly solid acid catalysts, including H14[NaP5W30O110], H14–P5, H14[NaP5W29MoO110], H14–P5Mo, and silica supported H14[NaP5W30O110], H14–P5/SiO2 have been used as catalysts for esterification of salicylic acid with aliphatic alcohols (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, t-butanol, 1-pentanol, and 2-pentanol) and benzylic alcohols (benzyl, 2-methylbenzyl, 2-chlorobenzyl, 4-bromobenzyl, 3-nitrobenzyl, and 4-methoxy benzyl) alcohol. The performance of different forms of Preyssler''s anion in the presence of dichloroethan as the solvent of choice was compared with H2SO4. In all cases, maximum of ester yields and product selectivity (100%) was observed by using H14–P5 as catalyst. The esterification reactions were extended with other aliphatic and aromatic acids. [Copyright &y& Elsevier]

This study is a new sight to the application of Preyssler heteropolyacid with the formula of [NaP 5 W 30 O 110 14− as a green and nontoxic inorganic crosslinker to prepare a supramolecular hydrogel using chitosan and polyvinyl alcohol. This novel Preyssler/chitosan/polyvinyl alcohol hydrogel was designed using a multicomponent synthesis method and characterized by multiple techniques including infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), force atomic microscopy (AFM), contact angle measurement, mechanical tests and thermogravimetric analysis (TGA). TGA was conducted to measure the weight loss of the synthesized hydrogel at a heating rate of 10 °C min−1 in the nitrogen atmosphere. It is evident that Preyssler is acting as a crosslinker which has high thermal degradation or high thermal stability. The FTIR of the synthesized hydrogel reveals no chemical changes during crosslinking. The resultant surface showed excellent hydrophilic ability and had a water contact angle (CA) of 19.8 ± 4. Results of the SEM revealed that the surface of the hydrogel film is homogeneous and continuous. The sample had a low elongation at break (1.84 ± 2.38%), due to strong hydrogen bonding interactions between the Preyssler, chitosan, and PVA. The performance of the synthesized hydrogel using Preyssler's anion was compared with chitosan/polyvinyl alcohol. In all cases, the maximum improvement was observed by using the Preyssler heteropolyacid. To expand the potential application of the synthesized hydrogel in water treatment, the removal of methyl orange and red pigment as common azo dye pollutants in the environment was selected as a test reaction to estimate the potential application of the synthesized hydrogel and found to be excellent. • This study is a new sight to the application of Preyssler heteropolyacid as crosslinker. • Preyssler/chitosan/polyvinyl alcohol hydrogel was synthesized and fully characterized. • A green and nontoxic inorganic crosslinker used to prepare supramolecular hydrogel. • The process as a green technology does not require harmful and corrosive crosslinkers. • The synthesized hydrogel is a good candidate to remove azo dyes from color wastewaters. [ABSTRACT FROM AUTHOR]

Polyoxometalate-based drugs have been selected by some researchers as alternative antitumor substances with promising results in suppression of tumor growth because of low toxicity towards the human body and high activity. In this research, for the first time, nanolipid-loaded Preyssler polyoxometalate with diameters of 230–250 nm was synthesized and characterized by the Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDAX), Atomic Force Microscopy (AFM), and Infrared (IR) spectroscopy. The nanoliposomes were found to be nearly spherical, without any agglomeration with the Entrapment Efficiency of 53.8%. In -vitro antitumor activity of the synthesized nanoliposomes was investigated using the MTT method on HepG2 tumor cells. Our findings showed enhanced anticancer activity for the nanolipid-loaded Preyssler (NLP) compared to the Sorafenib as a commercially drug at 72 h. Selectivity of the synthesized NLP and Sorafenib for cancer cells versus primary HFF cells was obtained as 4.2 and 2.2, respectively. The IC50 value of the loaded nanoliposomes for cancer cells and normal cells was equal to 470 and 2000 μg/mL, respectively at 72 h, which was much better compared to that of the Sorafenib (7 and 16 μg/mL, respectively). Unlabelled Image • This study is the first to explore the potential of nanolipid-loaded Preyssler and its inhibitory effects on HepG2 tumor cells. • Enhanced anticancer activity observed for nanolipid-loaded Preyssler compared with sorafenib as a commercially drug at 72 h. • This is the first time that Preyssler as an effective and selective drug acts on HepG2 tumor cells. • High yields, short reaction times, simplicity of operation and easy work-up procedure are some advantages of this protocol. • The synthesis does not require harmful drugs and organic solvents, thus could be termed as green nanotechnology for drug delivery. [ABSTRACT FROM AUTHOR]