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Inorganic Chemistry Communications (13877003) 180
This research focuses on the catalytic effect of transition metals substituted Wells-Dawson type polyoxometalates (M-WDPOMs; M = Mn, Fe, Co, Cu, Ni, and Zn) in epoxide ring-opening reactions. These catalysts were chosen for their sustainability, non-toxic nature, availability, low cost, environmental friendliness, and high electron transfer ability. The M-WDPOM compounds were prepared, characterized using various techniques, and their catalytic activities in ring-opening reactions of different epoxides with sodium azide and acetic anhydride were investigated. Azidolysis reactions were performed under reflux in a mixture of acetonitrile and water, while acetolysis reactions were conducted under solvent-free conditions. Among the different M-WDPOM catalysts, Fe-WDPOM demonstrated the highest catalytic performance in these ring-opening reactions with shorter reaction times and higher yields. Consequently, azidoalcohols and diacetates were produced efficiently with high to excellent yields (80–98 %). © 2025 Elsevier B.V.
Catalysis Letters (1572879X) 155(2)
A hybrid catalyst based on Mo132 as a Keplerate type polyoxometalate and MimAm as an ionic liquid was used as an effective catalyst for selective epoxidation of different alkenes with H2O2 as a green and safe oxidant. The effects of various parameters such as catalyst, oxidant amounts, reaction time, and temperature were also studied in selective epoxidation of cyclooctene. Moreover, under the optimal reaction conditions, the epoxidation of different alkenes was performed with 54–100% yields. Interestingly, this catalyst complies with the benefits of easy preparation, recovery, recycle, high catalytic activity, simplified workup, and flexible composition. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.
RSC Advances (20462069) 15(11)pp. 8777-8783
Silica-supported polyoxometalates [Si/AlO2]@[PWM] (M = Zn, Cu, Ni, Co, Fe, Mn, and Cr) were produced by immobilizing transition metal substituted Keggin-type polyoxometalates on cationic silica nanoparticles. These silica-supported polyoxometalates were then encapsulated with hexadecyltrimethylammonium bromide to obtain [Si/AlO2]@[PWM]@CTAB (M = Zn, Cu, Ni, Co, Fe, Mn, and Cr) to prevent polyoxometalate leaching. Characterization by FT-IR, TG-DTG, XRD, SEM, and TEM indicated that the polyoxometalate structure was retained after immobilization and encapsulation. These nanoscale compounds were used as heterogeneous catalysts in the oxidation of various alcohols, achieving very good to excellent yields with H2O2 as an oxidant, and demonstrating high reusability. These benefits introduce surfactant-encapsulated silica-supported polyoxometalates as highly efficient heterogeneous catalysts in different oxidation reactions. © 2025 The Royal Society of Chemistry.
Materials Advances (26335409) 5(14)pp. 5781-5793
Harmful industrial pollutants are the most important and substantial challenges in ecological and environmental processes. Therefore, environmental remediation of these types of toxic materials is an important issue. The main purpose of the present study is the catalytic reduction of some organic dyes and nitro aromatic compounds as toxic contaminants in the presence of polyoxometalates (POMs). At first, the transition metal-substituted Keggin-type POM-based melamine was prepared and identified using different techniques such as FTIR, XRD, TGA, and FE-SEM. Then, the catalytic performance of these synthesized compounds in the reduction of some nitro aromatic compounds and organic dyes was investigated. By copper-substituted Keggin-type POM-based melamine (CuPOM@melamine), the best result was obtained with higher conversion and shorter reaction time. All reactions were carried out using NaBH4 as the reducing reagent at room temperature and in water as solvent. Furthermore, the apparent rate constants were determined by considering pseudo first-order kinetic studies for these reactions. The main purpose of the present study is introducing an impressive way to eliminate hazardous industrial pollutants using POM-based melamine. The choice of melamine as a support for increasing the surface area, electron transfer ability and catalytic activity is another important aspect of this purpose. This effective system was used in water as the solvent and at room temperature. Easy preparation, nontoxicity, simple to operate, low-cost, environmentally friendly, and efficient catalytic activities are priorities of this system that could be applied in the environmental processes. © 2024 RSC.
Aramesh, N. ,
Reza bagheri, A. ,
Zhang, Z. ,
Yadollahi, B. ,
Kee lee, H. Coordination Chemistry Reviews (00108545) 507
Environmental pollution has been a threat since the industrial revolution. Environmental pollution has extensively increased in the last few decades because of human activity and the rapid expansion of modern industry and agriculture. Different pollutants like dyes, heavy metals, etc. can not only affect human health, but also that of other living things. Therefore, there is an urgent need for the application of suitable approaches and materials to mitigate toxic pollutants in the environment. Polyoxometalates (POMs), representing a group of metal-oxide clusters with high thermal stability, high negative charges, modification capability, and remarkable redox and ligand capabilities, are examples of materials used in environmental chemistry. They can function as remediation adsorbents and catalysts in pollution monitoring and control. This article gives a state-of-the-art overview of POMs and their synthetic strategies and presents the recent progress of POM-based materials (POMBMs) used in environmental pollution studies. It examines different POM-based composites and their applications in pollutant/contaminant monitoring (in conjunction with various analytical techniques) and abatement. Possible adsorption and catalytic degradation mechanisms are also described. Finally, the current challenges, gaps, future directions and prospects for improving the utility and applicability of POMBMs are presented. It is hoped that the article is timely and provides a comprehensive perspective on designing, constructing and applying POMs and POMBMs as adsorbents and/or catalysts for environmental pollution research. © 2024 Elsevier B.V.
Catalysis Communications (15667367) 185
In the present work, various transition metal substituted Keggin-type polyoxometalates/Ni-Al layered double hydroxide/graphene oxide (PWM/Ni-Al LDH/GO; M = Fe, Ni, Cu, Mn, Co, Cr, Zn) nanocomposites have been synthesized and utilized as catalysts in the epoxidation of alkenes. Results confirmed that in the epoxidation of alkenes, PWFe/Ni-Al LDH/GO nanocomposite could perform its role as the best catalyst. The selected nanocomposite evaluated as a heterogeneous catalyst in the green oxidation of various alkenes into the corresponding epoxides while aqueous hydrogen peroxide was used as an environmentally benign oxidant. The results of recovery and reusability experiments on PWFe/Ni-Al LDH/GO nanocomposite revealed that even after five times it could be easily reused without any considerable decrease in catalytic efficiency. © 2023 The Authors
Materials Chemistry and Physics (02540584) 296
The present study focuses on the development of an impressive way to eliminate toxic nitro aromatic compounds as hazardous industrial pollutants using polyoxometalate-based composites. For this purpose, transition metal substituted Keggin-type polyoxometalates were integrated on modified protonated graphitic carbon nitride (POMs@g-C3N4) via an electrostatic self-assembly strategy. These stable compounds are characterized by different techniques and used in the reduction of toxic nitro aromatic compounds. Among Cr, Mn, Fe, Co, Ni, Cu, and Zn, the composite containing copper substituted Keggin-type polyoxometalate (CuPOM@g-C3N4) presents the most respectable catalytic activity in these reduction reactions. Moreover, this efficient catalytic system is applied in the reduction of different toxic nitro aromatic compounds into the amino aromatic analogues with appropriate conversions and reaction times. Kinetic studies are also used to determine their apparent rate constants. This process is easy, low-cost, non-toxic, high potential catalytic performance, and environmental friendliness that could be accomplished in water as solvent and at room temperature. © 2023 Elsevier B.V.
New Journal of Chemistry (11440546) 46(38)pp. 18199-18206
In this work, covalently bonded folic acid and niobium substituted Wells-Dawson polyoxometalate, (Bu4N)5H4[P2W15Nb3O62]-folic acid, has been synthesized and characterized. Afterward, the bioactivity behavior of this hybrid compound against cervical (HeLa) and human breast (MCF-7) cancer cells, and also human fibroblast cells (HFB) was investigated. This intelligent hybrid compound could surprisingly knock down cancer cells (IC50 about 37, 49 and 110 μg mL−1 on HeLa, MCF-7 and HFB, respectively). A higher expression of folic acid on HeLa and MCF-7 cells could explain the greater cytotoxicity of this hybrid polyoxometalate. As folate receptor (FR) negative cells, the normal cells remained approximately 2- to 3-fold safer. The bioactivity effect of (Bu4N)5H4[P2W15Nb3O62] on HeLa and MCF-7 cells reaches IC-50 values of about 87 and 107 μg mL−1 respectively, which is about twice that of the as synthesized hybrid compound. Compared to methotrexate as a positive control, this hybrid polyoxometalate is about 2 to 3 times safer on healthy cells. Moreover, it has high potential for developing a selective therapeutic effect against FR-positive cancer cells. © 2022 The Royal Society of Chemistry.
Scientific Reports (20452322) 12(1)
The aim of this study is to fabricate a new scaffold appropriate for tissue regeneration with antimicrobial activity and ability of controlled drug delivery. In this regard, scaffold nanofibers were produced using poly (methyl methacrylate) (PMMA), Mo132 as a Keplerate polyoxometalate and metronidazole. The final scaffolds, obtained by electrospinning, represent the intrinsic features including exceptional doubling tensile strength, high hydrophilicity (126 ± 5.2° to 83.9 ± 3.2° for contact angle and 14.18 ± 0.62% to 35.62 ± 0.24% for water uptake), proper bioactivity and cell adhesion. Moreover, the addition of Mo132 and metronidazole enhances the biodegradation rate of resulted scaffolds compared to the pure PMMA membrane. The controlled release of metronidazole over 14 days efficiently inhibits the colonization of anaerobic microorganisms. Overall, the results demonstrate high potential of Mo132 and metronidazole-loaded PMMA scaffold for guided bone regeneration/guided tissue regeneration. © 2022, The Author(s).
Journal of Drug Delivery Science and Technology (17732247) 69
Wound healing is crucial because it entails a complex cellular process that complicates the design of scaffolds for therapeutic purposes. Present study is focused on the development of a new wound dressing based on polymethyl methacrylate nanofibers containing Mo72Fe30 as a Keplerate-type polyoxometalate with efficient and controlled delivery of metronidazole during wound healing. The hydrophilic nature of biocompatible Mo72Fe30 along with the antibiotic and wound healing properties of metronidazole were utilized to develop an efficient wound dressing. The efficient and controlled release of metronidazole was assisted by the presence of Keplerete as an anion and metronidazole as a cation. The nanofibers were prepared by electrospinning of appropriate solution and characterized by FT-IR, XRD, FE-SEM, EDX, TGA, and elemental analysis. The surface wettability, microstructure, water absorption capacity, mechanical properties, in-vitro biocompatibility, drug release behavior, and in-vivo wound healing of prepared dressings were also evaluated. The in-vivo animal studies (injury created on the back of Wistar rats) showed the complete healing of wounds after 14 days of being covered by wound dressing compared to a sterile gauze, which shows approximately 45% reduction in wound size. The amounts of wound closure using dressing were found to be 95.26 and 97.97% after 7 and 14 days of wounding, respectively. The overall results indicated the high potential of these nanofiber-based dressings for wound healing. © 2022 Elsevier B.V.
Journal of Solid State Chemistry (1095726X) 305
In the present study, molecular geometry, electronic structure, first row transition metal-polyoxometalate interactions, transition metal-H2O bonding, and simulated infrared (IR) spectrum of H2O ligated/unligated transition metal substituted Keggin type polyoxometalates ([PW11O39(MII/MIIOH2)]5-, MII = Cr, Mn, Fe, Co, Ni, Cu and Zn) have been studied through Density Functional Theory (DFT) calculations. From the results, it has been predicted that the interaction of H2O ligand with MII leads to a stable [PW11O39(MII-H2O)]5- complex, without spin crossing during water attachment. The calculations have also revealed that interaction of H2O ligand with [PW11O39(MII)]5- could be discussed in two different classes: when MII is Cr, Mn and Fe, the H2O molecule interacts directly to MII from O side, while for MII = Co, Ni, Cu and Zn, the H-bond interaction between H2O and O atoms around the M, leads to the stabilization of POM-H2O system. Moreover, it has been predicted that the binding properties of H2O strikingly depends on axial 3dz2 orbital of MII. In this regard, it has been exhibited that the affinity of H2O for MII in [PW11O39(MII)]5- with a filled 3dz2 orbital, is strongly reduced as measured by increasing in calculated MII-ligand distance. Also, strong contributions of MII 3d as well as the 2p orbitals of five oxygen donor atoms in polyoxometalate cluster results in the bonding interaction between MII and lacunary Keggin polyoxometalate. The DFT-derived IR spectra showed displacement and splitting in four previously known vibrational bands of Keggin-type polyoxometalate, α-[PW12O40]3-, owing to transition metal substitution and H2O ligation. © 2021 Elsevier Inc.
Ramezani-aliakbari, M. ,
Soltanabadi, A. ,
Sadeghi, H. ,
Varshosaz, J. ,
Yadollahi, B. ,
Hassanzadeh, F. ,
Rostami, M. Journal of Molecular Structure (00222860) 1240
In this work, trimethylated gallic acid (Eudesmic acid, EU) was selected for the synthesis of an organo-conjugate (EU2POMo) from TRIS modified Anderson-type manganese polyoxomolybdate (POMo) for the first time. EU2POMo was synthesized through amide bonding between POMo and EU using carbodiimide coupling strategy. Some of the quantum chemical properties of POMo and EU2POMo beside the DFT and TD-DFT calculations were done using the Gaussian program. The cytotoxicity was studied on breast cancer cell lines (MCF-7 and MDA-MB-231) comparing the Human Umbilical Vein Endothelial Cell line (HUVEC) using the MTT method. The cellular uptake was determined using the ICP-MS method, and the apoptosis value was checked by the flow cytometry technique on the MDA-MB-231 cell line. The structure was approved by FTIR, NMR spectroscopy as well as elemental analysis. Quantum chemical calculations proposed better stability and lower chemical potential for EU2POMo, and internal energy and dipole moment were higher in the EU2POMo. Both POMo and EU2POMo showed reasonable anti-cancer effects on breast cancer cell lines (MCF-7 and MDA-MB-231), and the results were somewhat in favor of POMo. Interestingly, EU2POMo showed no significant cytotoxicity on the HUVEC and was safer than POMo. Cellular uptake (33.5% versus 29.2%) and apoptosis value (28% versus 15%) in the case of EU2POMo were slightly better than POMo. In conclusion, this study aimed to introduce a novel, potent and safe anti-cancer Anderson type polyoxometalate to cancer studies. Based on results, this conjugate has sufficient potential for further cancer chemotherapy assessments, specifically breast cancer. © 2021 Elsevier B.V.
A new hybrid compound was synthesized via the covalent grafting of vanadium-substituted Wells-Dawson type polyoxometalate (Bu4N)5H4[P2W15V3O62] to folic acid. The cytotoxic effect of the resulted bioactive hybrid compound was investigated on cervical (HeLa) and human breast (MCF-7) cancer cells. Interestingly this smart hybrid compound could knockdown cancer cells (IC50 about 19 and 75 µgmL−1 for HeLa and MCF-7 respectively), while the normal cells, as a folate receptor (FR) negative cell, remained nearly untreated (IC50 about 317 µgmL−1). Higher cytotoxicity of this hybrid polyoxometalate on HeLa than MCF-7 cells could be attributed to the higher expression of folic acid on HeLa. The IC50 for (Bu4N)5H4[P2W15V3O62] on healthy cells (about 84 µgmL−1) showed four times improvement in the polyoxometalate biocompatibility by incorporation of folic acid. In comparison to methotrexate (as a positive control), this smart polyoxometalate-folic acid hybrid compound has a high potential for developing a significant and selective therapeutic effect against FR-positive cancer cells. © 2021 Elsevier Ltd
RSC Advances (20462069) 10(56)pp. 33718-33730
Herein, the geometry, electronic structure, Fe-ligand bonding nature and simulated IR spectrum of α-Keggin, lacunary Keggin, iron(ii/iii)-substituted and the important oxidized high-valent iron derivatives of Keggin type polyoxometalates have been studied using the density functional theory (DFT/OPTX-PBE) method and natural bond orbital (NBO) analysis. The effects of different Fe oxidation states (ii-vi) and H2O/OH−/O2−ligand interactions have been addressed concerning their geometry and electronic structures. It has been revealed that the d-atomic orbitals of Fe and 2p orbitals of polyoxometalate's oxygen-atoms contribute in ligand binding. Compared with other high valent species, the considered polyoxometalate system of [PW11O39(FeVO)]4−, possesses a high reactivity for oxygen transfer. © The Royal Society of Chemistry 2020.
Science of the Total Environment (00489697) 708
In this work, the catalytic activity of core-shell-type polyoxometalate (POM) composites, comprised from Keggin POMs encapsulated in Mo72Fe30 Keplerate, in the oxidation of various sulfides into corresponding sulfoxides or sulfones and oxidative desulfurization of dibenzothiophene with hydrogen peroxide are investigated. From the results, the catalytic activity of these Keggins encapsulated in Keplerate are better than parent ones and among them BW12 ⊂ Mo72Fe30 showed the best results. The operationally simple oxidation reactions at room temperature, high to excellent yields and chemoselectivity, short reaction times, and the use of H2O2 as oxidant are some of the other advantages in this catalytic system. Also, the synergistic effect of Keggin POMs and Mo72Fe30 Keplarate has been confirmed. © 2019 Elsevier B.V.
Journal Of The Iranian Chemical Society (1735207X) 17(11)pp. 2895-2900
In this work, homogeneous and heterogeneous oxidation of alcohols by H2O2 in the presence of [(n-C4H9)4 N]5[PW11ZnO39].3H2O and [PW11ZnO39]5− supported on Dowex 22 as catalysts have been investigated. Using water as a green solvent, different alcohols were converted into the corresponding aldehydes and ketones in high to excellent yields. Dowex 22 supported polyoxometalate, PW11Zn@Dowex, was also catalyzed highly robust and selective oxidation of unsaturated alcohols. Leaching and recycling experiments on supported catalyst revealed the excellent stability and reusability of this catalytic system. © 2020, Iranian Chemical Society.
Polyhedron (02775387) 156pp. 98-104
Different Keggin encapsulated in Keplerate polyoxometalates (Mo72Fe30, PMo12 ⊂ Mo72Fe30, SiMo12 ⊂ Mo72Fe30 and BW12 ⊂ Mo72Fe30) have been synthesized and their catalytic efficiency in the epoxidation of olefins with hydrogen peroxide investigated. Results were confirmed that Keggin encapsulated in Keplerates could show higher catalytic activity than parent ones. These POM catalysts lead to heterogeneous epoxidation of alkenes by hydrogen peroxide with green features of convenient recovery, steady reuse, high conversion and selectivity, and simple preparation. © 2018 Elsevier Ltd
Microporous and Mesoporous Materials (13871811) 247pp. 23-30
Herein, a new antitumor active polyoxometalate, (TBA)4H3[GeW9V3O40], has been introduced as an inorganic drug with enormous influence on brain cancer cells and its outstanding results against U87 cells have been described. Post-functionalization of this polyoxometalate produces a drug delivery vehicle which comprises both kinds of inorganic and organic drugs. This system is consisted of mesoporous silica nanoparticles as organic drug carrier, along with redox-responsive disulfide bonds for drug release into the cell at the same time. Moreover, a fluorescence dye has been attached to the polyoxometalate that allows for tracking the drug into the cell environment. This dual-functionalized polyoxometalate was utilized in a designed multidrug delivery system, and worked greatly against U87 cells and knocked down these cancer cells up to near 70% in 48 h. Due to its unique properties, this multidrug delivery vehicle is potent to be developed and used for various applications in cancer therapy. © 2017 Elsevier Inc.
Fareghi-alamdari, R. ,
Hafshejani, S.M. ,
Taghiyar, H. ,
Yadollahi, B. ,
Farsani, M.R. Catalysis Communications (15667367) 78pp. 64-67
A practical method for the selective epoxidation of alkenes was discovered using HxPMo12O40 <> H4Mo72Fe30(CH3COO)15O254 as a catalyst in the presence of H2O2 as a green oxidant. However, the simple catalyst system involving polyoxometalates and H2O2 exercised the most successful system in obtaining high to excellent yields of epoxide products for different alkenes, including aromatic and aliphatic alkenes at room temperature in water. The effectiveness of this catalyst is evidenced by 99% selectivity to epoxide and 97-99% efficiency of H2O2 utilization. The stability of PMo > Mo72Fe30 under a catalytic reaction has been confirmed by XRD, FT-IR and Raman spectroscopies. © 2016 Elsevier B.V. All rights reserved.
RSC Advances (20462069) 6(17)pp. 13609-13613
Wheel-shaped polyoxotungstate [Cu20Cl(OH)24(H2O)12(P8W48O184)]25- (Cu20 POM) was used as an efficient catalyst for the preparation of triazoles from the corresponding alkyl halides, sodium azide, and alkynes. In this click reaction, the three-component synthesis of 1,2,3-triazoles was performed under mild reaction conditions at room temperature and high to excellent yields were obtained. The isolation and purification processing of organic azides were avoided in this procedure, as they were prepared in situ. © The Royal Society of Chemistry 2016.
Jalilian, F. ,
Yadollahi, B. ,
Farsani, M.R. ,
Tangestaninejad, S. ,
Amiri rudbari, H. ,
Habibi, R. RSC Advances (20462069) 5(86)pp. 70424-70428
In this work, the catalytic perspective of three Keplerate polyoxometalates, Mo72M30 (M = V, Cr, Fe) in the epoxidation of various alkenes is considered. The catalytic reactions were performed in water under mild conditions and high to excellent conversions and selectivities were obtained using H2O2 as oxidant and Mo72Cr30 as the best catalyst. Keplerate POM catalysts have shown a very good recyclability, up to five times, without any appreciable decreases in catalytic activity and selectivity. © The Royal Society of Chemistry 2015.
Comptes Rendus Chimie (18781543) 18(4)pp. 391-398
Abstract 1,2-bis(2'-aminophenoxy)-4-methylbenzene provides a Schiff base by reaction with 2-pyridinecarboxaldehyde. The stereochemical rigidity of ortho-aminophenyl diamines causes this latter, as well as the corresponding nitro precursors, be chiral. The chiral conformation of the diamine precursor is maintained in the octahedral zinc(II) and cobalt(II) complexes prepared from the Schiff base. The crystal structures of [ZnL(NO3)(H2O)]NO3 and CoLCl2 complexes exhibit non-planar cis-α configurations with both enantiomers (Δ and Λ). This implies that in the Schiff base ligand the two α-diimine systems shape an octahedral cavity having the same chirality of the precursory diamine. © 2014 Académie des sciences.
Applied Organometallic Chemistry (02682605) 29(1)pp. 7-11
The catalytic performance of tetra-n-butylammonium salts of Keggin and Wells-Dawson sandwich-type polyoxotungstates, [M4 (PW9O34)2]m- and [M4(P2W15O56)2]n- (M = Mn2+, Fe3+, Co2+, Ni2+, Zn2+), in the oxidation of cyclooctene and cyclohexene with 30% hydrogen peroxide under various conditions was investigated. In comparison, Wells-Dawson sandwich-type polyoxometalates were found to be less active than Keggin ones. In both of them, those containing Zn and Fe gave higher conversions for different oxidation conditions. These catalysts showed very good reusability in the oxidation reaction. Copyright © 2014 John Wiley & Sons, Ltd.
RSC Advances (20462069) 5(94)pp. 76875-76882
Polyoxometalates (POMs) are a class of inorganic metal-oxygen clusters comprising many elements, with unique structures and molecular weights, which possess similar energy band structures to metal oxides. In this research, for the first time, a Keggin-type hybrid polyoxometalate [SiW11O39(Si(CH2)3NH2)2O] (Hybrid-POM) is used as a pure semiconductor thin film in the working electrode of an efficient dye-sensitized solar cell (DSC) which was fabricated with a D35 organic dye as the sensitizer and a one-electron fast redox mediator cobalt complex. The D35 dye is attached to the surface of the POM by a strong amide bond (D35@Hybrid-POM). For comparison, two DSCs were also fabricated with mesoporous anatase TiO2, with and without a titania blocking layer, under the same conditions of electrolyte, sensitizer and counter electrode. J-V measurements of the DSCs were obtained under AM1.5G irradiation and photoelectrochemical parameters like open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), voltage decay and the overall efficiency were measured and compared to the mesoporous titania cells. The J-V curves show a promising enhancement overall in the DSC with the D35@Hybrid-POM structure in comparison with other prevalent mesoporous titania cells. Incident photon to current conversion efficiency spectra of the D35@Hybrid-POM DSCs and mesoporous titania with TBL (titania blocking layer) working electrodes were also obtained. A maximum IPCE of about 91% was found for the DSC employing D35@Hybrid-POM which is about 30% higher than the DSC with the mesoporous titania layer. The voltage decay measurements, calculated electron lifetime and effective recombination order (β) showed that the electron lifetime becomes promisingly longer when we use the Hybrid-POM structure in the photoanode. Thus, these results show that the rates of recombination and electron transfer of the cobalt mediator system at the surface of Hybrid-POM are very slow. ©2015 The Royal Society of Chemistry.
Inorganic Chemistry Communications (13877003) 55pp. 135-138
In this work a water soluble polyoxometalate nano capsule, HxPMo12O40 ⊂ H4Mo72Fe30(CH3COO)15O254, with high stability was evaluated for the oxidation of various alcohols into the corresponding aldehydes and ketones by hydrogen peroxide. This environmentally and economically valuable catalyst allowed for using water as solvent and has not required any organic solvents. In the presence of very low amounts of catalyst high to excellent yields and selectivity were obtained. © 2015 Elsevier B.V. All rights reserved.
Journal Of The Iranian Chemical Society (1735207X) 12(7)pp. 1207-1212
Abstract In this work it was demonstrated that the sodium and potassium salts of a sandwich-type tetra-cobalt tungstophosphate, [Co4(H2O)2(PW9O34)2]10-, are efficient catalysts for the selective oxidation of alcohols into corresponding aldehydes with hydrogen peroxide in water. Among these two salts, Na10[Co4(H2O)2(PW9O34)2]·27H2O complex showed better catalytic activity for the alcohols' oxidation. Using trace amounts of catalyst, different benzylic and aliphatic hydroxyl groups were converted into the corresponding carbonyl compounds in high to excellent yields. Graphical Abstract: In this work green and efficient catalytic oxidation of various alcohols to aldehydes and ketons with a sandwich-type tetra-cobalt tungstophosphate, [Co4(H2O)2(PW9O34)2]10-, is developed. High-to-excellent yields for oxidation of different alcohols by hydrogen peroxide in water are some advantageous of this catalytic system. © 2015 Iranian Chemical Society.
Dalton Transactions (14779226) 44(4)pp. 1709-1715
Herein, the synthesis, characterization and photocatalytic application of a novel hybrid polyoxometalate, which can absorb light in the visible region, are reported. This hybrid material was synthesized by attaching a monovacant polyoxometalate, (SiW11O39), through a (3-aminopropyl)triethoxysilane linker to the anthracene. The hybridization with anthracene drastically decreased the band gap of the polyoxometalate and made it a good candidate for utilization in photocatalytic applications under visible light. In this aspect, this photocatalyst was used for the oxidation of alcohols into the corresponding carbonyl compounds under an O2 atmosphere. Different benzylic and aliphatic alcohols were treated in the presence of this photocatalyst under the optimum reaction conditions and provided the corresponding carbonyl compounds in high yields. This journal is © 2015 The Royal Society of Chemistry.
Dianat, S. ,
Bordbar, A. ,
Tangestaninejad, S. ,
Yadollahi, B. ,
Amiri, R. ,
Zarkesh-esfahani, H. ,
Habibi, P. Journal of Inorganic Biochemistry (01620134) 152pp. 74-81
Free and nanosized starch and lipid encapsulated Na5[PMo10V2O40]·nH2O complexes (abbreviated as PMoV, SEP and LEP, respectively) have been prepared and structurally characterized by Fourier transform infrared (FT-IR) spectroscopy, inductively coupled plasma (ICP) analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The results show that the PMoV retains its parent structure after encapsulation by starch and lipid nanoparticles. The in vitro antitumor activity of PMoV in its free and nano-encapsulated forms was investigated using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay that was carried out on two types of human cancer cells, MCF-7 (breast cancer cells) and HEK-293 (Human Embryonic Kidney). The results represent the enhancement of cell penetration and antitumor activity of PMoV due to its encapsulation in starch or lipid nanoparticles. However, this observed enhancement for the lipid relative to the starch nanocapsule can be attributed to its smaller size. In order to investigate the molecular nature of antitumor activity, the binding properties of PMoV with calf thymus DNA (ctDNA) were also comprehensively evaluated using UV-vis absorption spectroscopy, fluorescence quenching and fluorescence Scatchard plots. The results rule out the intercalating binding mode and propose the groove or outside stacking binding for PMoV. However, a biphasic binding behavior that is due to the change in the binding mode was observed by varying of [PMoV]/[ctDNA] mole ratio. The results of cell culture assay and DNA binding experiments represent that the rate of cell penetration is more important than DNA binding affinity in the antitumor activity for POM. © 2015 Elsevier Inc.
Jalilian, F. ,
Yadollahi, B. ,
Farsani, M.R. ,
Tangestaninejad, S. ,
Amiri rudbari, H. ,
Habibi, R. Catalysis Communications (15667367) 66pp. 107-110
The catalytic activity of three Keplerate polyoxometalates Mo72M30 (M = V, Cr, Fe) was examined in the H2O2-based oxidation of different sulfides in water. Various sulfides were successfully converted into the corresponding sulfones under mild reaction conditions with high to excellent yields. The recyclability of Keplerate POM catalysts did not show a significant loss of catalytic activity up to five times. The use of water and hydrogen peroxide as green solvent and oxidant makes these reactions interesting from environmental and economic points of view. © 2015 Elsevier B.V. All rights reserved.
Applied Organometallic Chemistry (02682605) 29(8)pp. 561-565
[PW11ZnO39]5- was immobilized on activated carbon and characterized using Fourier transform infrared, X-ray diffraction, Brunauer-Emmett-Teller and elemental analysis techniques. Effective oxidation of various alcohols with hydrogen peroxide was performed in the presence of this catalyst. Easy separation of the catalyst from the reaction mixture, cheapness, high activity and selectivity, stability as well as retained activity in subsequent catalytic cycles make this supported catalyst suitable for small-scale synthesis. Copyright © 2015 John Wiley & Sons, Ltd.
Polyhedron (02775387) 99pp. 260-265
Zn-Al layered double hydroxides pillared by Fe(III) substituted Keggin type polyoxometalate, [Zn2Al(OH)6](NO3)0.6(PW11FeO39)0.1·mH2O (LDH-PWFe), was synthesized by anion exchange method. The synthesized compound was characterized using various techniques such as FTIR, XRF, XRD, TGA, and BET. The resulting LDH-PWFe was assessed as catalyst in the green oxidation of alcohols with aqueous H2O2 as the oxidant. Results showed that, LDH-PWFe is an efficient catalyst for the oxidation of alcohols into corresponding aldehydes with good to excellent conversions and excellent selectivity. Recovery and reusability experiments of the catalyst demonstrated that, it could be recycled and reused at least five times without manifest loss of activity and selectivity. © 2015 Elsevier Ltd. All rights reserved.
Polyhedron (02775387) 76pp. 102-107
The tetra-n-butylammonium (TBA) salts of Keggin and Wells-Dawson sandwich type polyoxotungstates, [M4(PW9O34) 2]m- and [M4(P2W 15O56)2]n- (M = Mn 2+, Fe3+, Co2+, Ni2+ and Zn 2+), proved to be effective catalysts for the oxidation of benzylic alcohols to the corresponding aldehydes with 30% hydrogen peroxide in acetonitrile. The Wells-Dawson type polyoxometallates showed lower activity than the Keggin ones, and both the Zn substituted polyoxometallates depicted higher conversions. Oxidation of different benzylic alcohols with electron withdrawing and electron donating substituents gave high to excellent yields in the presence of Zn substituted POMs. © 2014 Elsevier B.V. All rights reserved.
Farsani, M.R. ,
Yadollahi, B. ,
Amiri rudbari, H. ,
Amini, A. ,
Caradoc-davis, T. ,
Price, J.R. Inorganic Chemistry Communications (13877003) 43pp. 39-44
A stable sandwich type Keggin polyoxometalate, Na4K 5[K3Cu3(NO3)(A-α-PW 9O34)2], has been synthesized and crystallized by a simple reaction method. Elemental analysis, FTIR, UV-vis, X-ray single crystal, thermal gravimetry, and cyclic voltammetry were used for the characterization of synthesized POM. The TBA salt of [K3Cu 3(PW9O34)2]9 - revealed high catalytic activity and 74-99% selectivity in the liquid phase epoxidation of alkenes with aqueous H2O2. The X-ray structure of this complex reveals that three Cu(II) ions are sandwiched between two A-α-PW9O34 moieties and that a nitrate monoanion is encapsulated in the same plane as the three Cu(II) atoms. The nitrate is coplanar with the three copper atoms, which are each in a distorted square-pyramidal environment. After recrystallization, the NO3 - group in the central belt didn't exit, in which this phenomenon is attributed to the type of counterion in the complex (as a result of mixing Na+ and K+ as counterions). This compound showed excellent stability in different pH and also didn't dissociate with hydrogen peroxide. © 2014 Elsevier B.V.
Tetrahedron Letters (00404039) 55(29)pp. 3923-3925
The catalytic oxidation of sulfides into the corresponding sulfones by a chromium substituted Keggin type polyoxometalate, (TBA)4[PW 11CrO39]·3H2O, was achieved using mild reaction conditions. Excellent yields were obtained using four equivalents of 30% H2O2. Under these reaction conditions, the sulfide group was highly reactive and other functional groups such as hydroxyl or a double bond were unaffected. Using a commercially available, eco-friendly, and cheap oxidant, mild reaction conditions, operational simplicity, practicality, short reaction times, high to excellent yields, and excellent chemoselectivity are some of the advantages of this catalytic system.
Inorganic Chemistry Communications (13877003) 50pp. 113-116
Solvent-free oxidation of sulfides into sulfones by 30% hydrogen peroxide has been achieved using chromium substituted Keggin type polyoxometalate under mild reaction conditions in 94-100% yield. This catalytic system showed excellent activity in the oxidation of sulfide groups. The other active functional groups such as hydroxyl and C=C bond have been tolerated. © 2014 Elsevier B.V. All rights reserved.
Journal of Molecular Catalysis A: Chemical (13811169) 392pp. 8-15
Fe(III) substituted Keggin type polyoxometalate in amorphous silica matrix, (n-C4H9)4N)4[PW 11FeO39]/SiO2 (PWFe/SiO2), has been synthesized by sol-gel method. The synthesized PWFe/SiO2 composite was characterized by various analytical and spectroscopic techniques. Results indicated that the primary Keggin structure remain after incorporation in silica matrix. As a heterogeneous catalyst, PWFe/SiO2 composite showed an elevated catalytic activity and selectivity with high to excellent yields for oxidation of alcohols into aldehydes by H2O2. The stability and reusability of the catalyst was very high, so these composites are suitable for the heterogeneous catalysis by hydrogen peroxide. © 2014 Elsevier B.V.
Inorganic Chemistry Communications (13877003) 28pp. 37-40
Various β-aminoalcohols were prepared by the ring opening reaction of epoxides with aromatic amines in the presence of Fe(III) substituted Wells-Dawson type polyoxometalate, α2-[(n-C4H 9)4N]7P2W17FeO 61·3H2O, as an efficient catalyst. The reaction was performed under neutral condition at room temperature and afforded the corresponding products in high to excellent yields. © 2012 Elsevier B.V.
Nadealian, Z. ,
Mirkhani, V. ,
Yadollahi, B. ,
Moghadam, M. ,
Tangestaninejad, S. ,
Mohammadpoor baltork, I. Journal of Coordination Chemistry (10290389) 66(7)pp. 1264-1275
Inorganic-organic hybrid catalysts 1-POM(M) were prepared by electrostatic interaction between transition metal-substituted polyoxometalates, {[PW11MO 39]4- [M = Cr(III), Fe(III)], [PW11MO39]5, [M= Mn(II), Co(II), Ni(II), Cu(II), Zn(II)], [PW11VO40]4-}, and branched organic polyammonium, (tris[2-(dimethylammonium)ethyl]-1,3,5- benzenetricarboxylate), and characterized by elemental analyses, UV-vis and FT IR spectroscopic techniques, XRD, SEM, and Thermogravimetric-Differential thermogravimetric analyses. The hybrid material 1-POM(Zn) was an efficient and selective heterogeneous catalyst in the oxidation of benzylic alcohols to their corresponding carbonyl compounds with hydrogen peroxide. The catalyst was reused several times without significant loss of catalytic activity. © 2013 Taylor & Francis.
Nadealian, Z. ,
Mirkhani, V. ,
Yadollahi, B. ,
Moghadam, M. ,
Tangestaninejad, S. ,
Mohammadpoor baltork, I. Journal Of The Iranian Chemical Society (1735207X) 10(4)pp. 777-782
The catalytic activity of [bmim]5[PW11ZnO 39]·3H2O as a hybrid catalyst was studied in the oxidation of various alkenes in acetonitrile, using hydrogen peroxide as oxygen source. The effect of reaction parameters such as type of solvent and oxidant, amount of catalyst and oxidant, and temperature was also investigated. From our results, [bmim]5[PW11ZnO39]·3H 2O hybrid catalyst gave higher yields and selectivity in the oxidation of alkenes and was reused four times without loss of its catalytic activity. © 2013 Iranian Chemical Society.
Nadealian, Z. ,
Mirkhani, V. ,
Yadollahi, B. ,
Moghadam, M. ,
Tangestaninejad, S. ,
Mohammadpoor baltork, I. Journal of Coordination Chemistry (10290389) 65(6)pp. 1071-1081
Various organic-inorganic hybrid compounds, [bmim] x [PW 11MO 39]3H 2O {(bmim: 1-n-butyl-3- methylimidazolium) and [M=V(IV), Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II)]}, were prepared and characterized by elemental analysis, UV-Vis, FT-IR, and TGA. The synthesized hybrid compounds were used as catalysts in oxidation of various alcohols with hydrogen peroxide in acetonitrile. The effect of the transition metal on the catalytic activity was in the order, Zn>Fe>Ni>Cr>Co>V>Mn>Cu. In this catalytic system, the effects of other parameters such as the type of solvent, amount of oxidant and catalyst, and the temperature were also investigated. [bmim] 5[PW 11ZnO 39]3H 2O was reused several times without loss of catalytic activity. © 2012 Copyright Taylor and Francis Group, LLC.
Dianat, S. ,
Tangestaninejad, S. ,
Yadollahi, B. ,
Bordbar, A. ,
Moghadam, M. ,
Mirkhani, V. ,
Mohammadpoor baltork, I. Journal of Molecular Liquids (18733166) 174pp. 76-79
Polyoxometalates (POMs) have shown a great potential of antitumor and antiviral activities; take into account, in this work we investigated the stability of a series of heteropolyoxotungstate-amino acids, heteropolyoxomolybdate-amino acids and the corresponding 12-heteropoly acids at different experimental conditions such as pH, buffer concentration, and the type of counter ion using UV-vis spectroscopy. Furthermore, the effect of tyrosine and ornithine were investigated as a counter ion, on the stability of POMs. The results indicated that degradation of these POMs in aqueous solutions follows pseudo-first order reaction kinetics according to the order of H 4SiW 12O 40 > H 3PW 12O 40 > H 4SiMo 12O 40 > H 3PMo 12O 40 for stability with respect to increasing of pH. The stability of POM increases in the presence of these amino acids. © 2012 Elsevier B.V.
Applied Organometallic Chemistry (02682605) 25(2)pp. 83-86
Herein, we want to report a simple and convenient way for protection-deprotection of alcohols in the presence of ammonium decatungstocerate(IV) {(NH4)8[CeW10O 36]·20H2O} as catalyst under ambient temperature in CH3CN. Using 0.002 mmol of the catalyst, various alcohols and phenols were transformed easily to the corresponding TMS ethers in excellent yields. In the second part, various TMS ethers were successfully converted to the parent hydroxyl compounds in the presence of the ammonium decatungstocerate(IV) catalyst. © 2010 John Wiley & Sons, Ltd.
Catalysis Communications (15667367) 10(6)pp. 842-847
Fe(III) substituted Keggin type polyoxometalate ((TBA)4PFeW11O39 · 3H2O) is an effective catalyst for the ring opening of epoxides with aromatic amines under neutral and mild conditions at room temperature. This regio- and chemoselective reaction proceeds rapidly and affords the corresponding β-aminoalcohols in excellent yields. © 2008 Elsevier B.V. All rights reserved.
Electrochimica Acta (00134686) 54(12)pp. 3495-3500
[PFeW11O39]4- (PFeW11) supported on the surface of 3-aminopropyl(triethoxy)silane modified silica gel was synthesized and used as a bulk modifier to fabricate a renewable three-dimensional chemically modified electrode. The electrochemical behavior of the modified electrode was investigated. Cyclic voltammetry studies showed that the PFeW11 on the electrode surface sustained the same electrochemical properties as that of the PFeW11 in solution. The preparation of chemically modified electrode is simple and quiet reproducible using inexpensive material. The modified electrode had high electrocatalytic activity toward H2O2 reduction and it was successfully applied as an electrochemical detector to monitor H2O2 in flow injection analysis (FIA). The electrocatalytic peak current was found to be linear with the H2O2 concentration in the range 10-200 μmol L-1 with a correlation coefficient of 0.998 and a detection limit (3σ) of 7.4 μmol L-1 H2O2. The electrode has the remarkable advantage of surface renewal owing to bulk modification, as well as simple preparation, good mechanical and chemical stability and reproducibility. © 2009 Elsevier Ltd. All rights reserved.
Eslami, A. ,
Nasseri s., ,
Yadollahi, B. ,
Mesdaghinia, A. ,
Vaezi f., ,
Nabizadeh, R. Iranian Journal Of Public Health (22516085) 38(2)pp. 18-26
Background: Methyl tert-butyl ether (MTBE) has been commercially used as an octane enhancer to replace tetraethyl lead in gasoline since 1979. The high mobility, water solubility, and resistance to natural attenuation associated with MTBE may result in contamination of ground and surface waters. In this investigation the degradation of aqueous MTBE at relatively high concentrations was studied by UV-vis/TiO2/O2 photocatalytic process. The effect of important operational parameters such as pH, oxygen flow, catalyst loading, and irradiation time were also studied. Methods: Concentration of MTBE and intermediates such as tert-butyl formate (TBF) and tert-butyl alcohol (TBA) were measured using a gas chromatograph equipped with flam ionization detector and combined with headspace sampler. Results: The time required for complete degradation increased from 15 to 150 min, when the initial concentration was increased from 10 to 500 mg/L. The first order rate constant for degradation of MTBE from the hydroxyl radical was estimated to be 0.266 to 0.033 min-1 as the concentration increased from 10 to 500 mg/L. Study on the overall mineralization monitored by total organic carbon (TOC) analysis showed that in the initial concentration of 100 mg/L MTBE, complete mineralization was obtained after 110 min under UV-vis/TiO2/O2 photocatalytic process. Conclusion: The data presented in this paper clearly indicate that UV/TiO2/O2 advanced oxidation process provides an efficient treatment alternative for the remediation of MTBE contaminated water.
Talanta (00399140) 74(4)pp. 909-914
α-PW12O40 3- (PW12) supported on the surface of silica gel derivatized by 3-aminopropyl(triethoxy)silane (devoted briefly as SiNH3PW12) was synthesized and used as bulk modifier to fabricate a renewable three-dimensional chemically modified electrode. The electrochemical behavior of the modified electrode was characterized by cyclic voltammetry. There is an ionic bonding character between PW12 and the surface amino groups of modified silica, which greatly improves the stability of SiNH3PW12-modified carbon paste electrode due to insolubility of silica gel in water. The SiNH3PW12 bulk-modified carbon paste electrode not only maintains the electrochemical activity of PW12, but also exhibits remarkable advantages of renewability, as well as simple preparation and inexpensive material. The modified electrode offers an excellent and stable electrocatalytic response for the reduction of IO3 - and hydrogen peroxide. The SiNH3PW12-CPE is successfully applied as an electrochemical detector to monitor IO3 - in flow injection analysis (FIA). The catalytic peak current was found to be linear with the IO3 - concentration in the range 5 × 10-6 to 1 × 10-3 mol L-1. The detection limit of the proposed method was found to be 3.1 × 10-6 mol L-1 for IO3 - determination. © 2007 Elsevier B.V. All rights reserved.
Eslami, A. ,
Nasseri, S. ,
Yadollahi, B. ,
Mesdaghinia, A. ,
Vaezi, F. ,
Nabizadeh, R. ,
Nazmara, S. Journal of Chemical Technology and Biotechnology (02682575) 83(11)pp. 1447-1453
Background: Over the past several decades methyl tert-butyl ether (MTBE) as additive to gasoline, intended to either boost ratings of fuel or to reduce air pollution, has been accepted worldwide. Since MTBE has high water solubility, the occurrence of fuel spills or leaks from underground storage tanks or transferring pipeline has led to the contamination of natural waters. In this study the degradation of aqueous MTBE at relatively high concentrations was investigated by a UV-visible/ZnO/H2O2 photocatalytic process. The effects of important operational parameters such as pH, amount of H2O2, catalyst loading and irradiation time were also investigated. Concentration of MTBE and intermediates such as tert-butyl formate and tert-butyl alcohol were measured. Results: Time required for complete degradation increased from 20 to 150 min when the initial concentration was increased from 10 to 500mg L-1. The first-order rate constants for degradation of MTBE were estimated to be 0.183-0.022 min-1 as the concentration increased from 10 to 500mg L-1. Study of the overall mineralization monitored by total organic carbon analysis showed that at an initial concentration of 100mg L-1 MTBE complete mineralization was obtained after 100 min under UV-visible/ ZnO/H2O2 photocatalysis. Conclusion: The data presented in this paper clearly indicated that UV-visible/ZnO/O2 as an advanced oxidation process provides an efficient treatment alternative for the remediation of MTBE-contaminated waters. © 2008 Society of Chemical Industry.
Catalysis Letters (1572879X) 113(3-4)pp. 120-123
The catalytic efficiency of transition metal substituted polyoxometalates in the azidolysis of 1,2-epoxides has been studied in acetonitrile/water, using NaN3 as the source of the azido group. The reaction is regioselective and afforded the corresponding products in high to excellent yields under mild reaction conditions. Fe (III) substituted polyoxometalate was identified as the optimal catalyst. © Springer Science+Business Media, LLC 2007.
Eslami, A. ,
Nasseri, S. ,
Yadollahi, B. ,
Mesdaghinia, A. ,
Vaezi, F. ,
Nabizadeh, R. Iranian Journal of Environmental Health Science and Engineering (17352746) 4(4)pp. 215-222
The oxygenate methyl tert-butyl ether is added to gasoline to increase the octane level and to reduce carbon monoxide and hydrocarbon emissions by vehicles. The high mobility, water solubility, and resistance to natural attenuation associated with methyl tert-butyl ether may result in contamination of ground and surface waters. In this research the degradation of aqueous methyl tert-butyl ether at relatively high concentrations was investigated by UV-vis/TiO2/H2O2 photocatalytic process. The effect of important operational parameters such as pH, amount of H2O2, catalyst loading, and irradiation time were also studied. Concentrations of methyl tert-butyl ether and intermediates such as tert-butyl formate and tert-butyl alcohol were measured over a 180 min period, using a gas chromatograph equipped with flame ionization detector and cobined with headspace sampler. Results showed that the time required for complete degradation increased from 30 to 180min, when the initial concentration was increased from 10 to 500mg/ L. The first order rate constant for degradation of methyl tert-butyl ether from the hydroxyl radical was estimated to be 0.177 to 0.022 1/min as the concentration increased from 10 to 500mg/L. Study on the overall mineralization monitored by total organic carbon (TOC) analysis showed that in the initial concentration of 100mg/L methyl tert-butyl ether, complete mineralization was obtained after 110min under UV-vis/TiO2/ H2O2 photocatalytic process.
Chemistry Letters (03667022) 36(5)pp. 676-677
Iron(III)-substituted polyoxometalate (TBA)4PFeW 11O39· 3H2O, has been demonstrated as an efficient catalyst in the ring opening of 1,2-epoxides with acetic anhydride for the one-pot synthesis of 1,2-diol esters in high to excellent yields under solvent-free condition. Copyright © 2007 The Chemical Society of Japan.
Monatshefte fur Chemie (00269247) 137(2)pp. 235-242
Efficient ring opening of epoxides under mild conditions is reported. Potassium dodecatungstocobaltate(III) trihydrate was used as an efficient catalyst for the alcoholysis and acetolysis of epoxides. Conversion of epoxides to thiiranes was also performed efficiently in the presence of this catalyst. © Springer-Verlag 2005.
Catalysis Letters (1572879X) 101(1-2)pp. 93-97
A mild, convenient and efficient ring opening of oxiranes with aromatic amines was catalyzed by ammonium decatungstocerate (IV) in acetonitrile. The reaction afforded the corresponding products in 92-100% yields. The catalyst was reused for several times with consistent activity. Equation presented. © Springer Science+Business Media, Inc. 2005.
Monatshefte fur Chemie (00269247) 135(10)pp. 1257-1263
Efficient esterification of primary and sterically-hindered secondary or tertiary alcohols with acetic anhydride was achieved in the presence of ammonium decatungestocerate(IV) icosahydrate, (NH4)8[CeW 10O36]·OH2O, as catalyst in high yields. Primary and secondary alcohols were also converted to their corresponding acetates and formates with acetic acid and ethyl formate in the presence of this catalyst. Easy work-up, non-toxicity, reusability, and stability of the catalyst are noteworthy advantages of this method. © Springer-Verlag 2004.
Synthetic Communications (00397911) 34(15)pp. 2823-2827
Titanium dioxide (TiO2) efficiently catalyze the reaction of a variety of epoxides with ammonium thiocyanate in refluxing acetonitrile to afford the corresponding thiirane in high to excellent yields.
Chemistry Letters (03667022) 32(11)pp. 1066-1067
Keggin type polyoxometalates can be used as catalysts for the activation of 30% aqueous hydrogen peroxide for the selective transformation of various organic substrates. In this paper, results are presented for the oxidation of sulfides to sulfoxides in high to excellent yields using 30% aqueous H 2O2 as oxidant and [PZnMo2W9O 39]5- as catalyst in acetonitrile.
Tetrahedron (14645416) 59(41)pp. 8213-8218
Epoxides can be cleaved in a regio- and stereoselective manner under neutral conditions with alcohols and acetic acid in the presence of catalytic amounts of decatungstocerate(IV) ion, ([CeW10O36] 8-), affording the corresponding β-alkoxy and β-acetoxy alcohols in high yields. In water, ring opening of epoxides occurs with this catalyst to produce the corresponding diols in good yields. © 2003 Elsevier Ltd. All rights reserved.
Catalysis Letters (1572879X) 91(1-2)pp. 129-132
Various types of oxiranes react with acetone in the presence of catalytic amounts of ammonium decatungstocerate (IV) icosahydrate, (NH4) 8[CeW10O36]. 20H2O to give 1,3-dioxolanes. The 1,3-dioxonation of cyclohexane oxide with acetone using catalytic amounts of various polyoxometalate complexes (0.04M) was also examined. Ammonium decatungstocerate icosahydrate was prepared using Peacock's procedure. It was reported that (NH4)8[CeW 10O36]. 20 H2O can be used as an effective catalyst for the conversion of oxiranes to thiiranes.
Monatshefte fur Chemie (00269247) 133(3)pp. 323-327
Alcohols and phenols are converted to esters in a mild, clean, and efficient reaction with acetic anhydride in the presence of a catalytic amount of potassium dodecatungstocobaltate trihydrate (K5CoW12O40· 3H2O).
Synthetic Communications (00397911) 32(6)pp. 863-867
Alcohols and phenols were efficiently acetylated with acetic anhydride without solvent in the presence of 0.01 molar equiv. of cobalt polyoxometalate (CoW12O405-).
Journal of Industrial Pollution Control (discontinued) (09702083) 17(1)pp. 67-73
The photoassisted oxidation of water containing paramethyl thiophenol (PMTP) was investigated, over a heterogeneous catalyst of TiO2 (anatase/rutile) in a photocatalytic reactor. The effect of some physical and chemical parameters such as irradiation time, amount of TiO2, flow of O2 and pH were studied in order to optimise the process. Carbon dioxide an d sulphate ion yield measurements indicte that almost complete minzeralization occurs in the final phase of oxidation.
Catalysis Letters (1572879X) 75(3-4)pp. 205-207
A mild and efficient preparation of 1,3-dioxolanes from epoxides and acetone has been carried out in high to excellent yields under catalysis of potassium dodecatungstocobaltate trihydrate (K5CoW12O40·3H2O) (0.01 molar equiv.).
Tetrahedron (14645416) 57(39)pp. 8333-8337
Acetylation and formylation reactions of alcohols with ethyl acetate, acetic acid and ethyl formate were catalyzed with potassium dodecatungstocobaltate trihydrate (K5CoW12O40·3H2O) in a mild, efficient and convenient method with high to excellent yields. © 2001 Elsevier Science Ltd. All rights reserved.
Pollution Research (discontinued) (02578050) 20(3)pp. 295-298
2-Mercaptobenzothiazole (MBT) is known as a widespread, toxic and poorly biodegradable pollutant. In this study, the results of photocatalysed degradation of MBT, an industrial pollutant, in aqueous solutions using suspended titanium dioxide are presented. The rate of MBT degradation as a function of pH, amount of TiO 2 and flow of O 2 was investigated and their optimum values were obtained. Carbon dioxide, ammonia and sulphate ion yield measurements indicate that almost complete mineralization occurs in the final phase of oxidation with some indication of benzothiazole-2-sulfonate (BTSO 3) as intermediate.
Applied Catalysis B: Environmental (18733883) 33(1)pp. 57-63
The photocatalytic oxidation of aqueous solutions of 2-mercaptobenzothiazole (MBT), 2-mercaptobenzimidazole (MBI), 2-mercaptobenzoxazole (MBO), 2-mercaptopyridine (MP), para-tolylmercaptan (PTM) was investigated over a heterogeneous catalyst of TiO2, in a photocatalytic reactor. The effect of some physical and chemical parameters such as amount of catalyst, flow of oxygen, pH and time of irradiation were studied in order to optimise the process. These mercaptans are almost completely mineralised to carbon dioxide, ammonia and sulphate ion by photocatalytic method. The results obtained from photocatalytic oxidation of MBT have led us to propose a compound with the sum formula of benzothiazol-2-sulfonate (BTSO3) to be a main intermediate. © 2001 Elsevier Science B.V. All rights reserved.
Tetrahedron Letters (00404039) 42(38)pp. 6771-6774
Mild and easy deprotection of benzylic dioxolanes to carbonyl compounds (in refluxing dry acetone) and trimethylsilyl ethers to alcohols in acetonitrile at ambient temperature has been carried out in excellent yields under K5CoW12O40·3H2O (0.01 molar equiv.) catalysis. © 2001 Elsevier Science Ltd. All rights reserved.
Tetrahedron Letters (00404039) 42(15)pp. 2851-2853
A simple, mild and effective method for tetrahydropyranylation of a variety of alcohols and cleavage of their tetrahydropyranyl ethers at ambient temperature in the presence of K5CoW12O40·3H2O as the catalyst with high turnovers is described. © 2001 Elsevier Science Ltd.
Journal of Chemical Research - Part S (13645560) (11)pp. 515-517
Alkens are transformed to their corresponding epoxides in high yields and with high selectivity by ultrasonic irradiation and sodium periodate in the presence of catalytic amounts of manganese porphyrin supported on Amberlite IRA-400 ion-exchange resin (MnTPPS-Ad).
Chemistry Letters (03667022) (6)pp. 511-512
Zinc heteropolyanion, PZnMo2W9O395-, was found to be an efficient catalyst for alkene epoxidation and oxidation of alkylaromatic compounds with 30% H2O2. Epoxide selectivities in the range of 80 to 100% was observed.
