A serial of ordered meso-macroporous phosphotungstic acid(HPW) supported on SiO2 nanocomposites were successfully prepared by a homogeneous precipitation method, using monodispersed polystyrene(PS) microspheres and ca...A serial of ordered meso-macroporous phosphotungstic acid(HPW) supported on SiO2 nanocomposites were successfully prepared by a homogeneous precipitation method, using monodispersed polystyrene(PS) microspheres and cationic surfactant as structure directing agent. These nanocomposites were used as catalysts for oxidative desulfurization(ODS) of model fuel. The materials were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), N2 adsorption-desorption isothrem, X-ray diffraction(XRD), and Fourier transform infrared spectra(FTIR). The characterization results suggested that the as-prepared material possessed ordered meso-macroporous architectures with Keggin type phosphotungstic acid dispersed homogeneously in SiO2 matrix. Under the selected reaction conditions, dibenzothiophene(DBT) in model fuel can be removed within 2 h at room temperature(30 ℃). In addition, only 1.2% of efficiency lose than the fresh catalyst even after 5 cycles.展开更多
Direct synthesis of dimethyl carbonate （DMC） from methanol and carbon dioxide over Co1.5PW12O40 in liquid and in gas phase is investigated. The synthesized catalyst has been characterized by means of FTIR and XRD. L...Direct synthesis of dimethyl carbonate （DMC） from methanol and carbon dioxide over Co1.5PW12O40 in liquid and in gas phase is investigated. The synthesized catalyst has been characterized by means of FTIR and XRD. Liquid phase experiment results showed that high pressures are favorable for the synthesis of DMC. However, DMC formation is limited by the reaction with co-produced water. DMC selectivity is more strongly dependent on the temperature than on the pressure of CO2. As for the reactions in gas phase, it has been found that both CH3OH conversion and DMC selectivity decreased with increasing temperature, owing to the decomposition of DMC at high temperatures. High temperatures and more amount of Co1.5PW12O40 catalyst favor the formation of dimethoxymethane （DMM） and methyl formate （MF）.展开更多
Parent compounds of cyclopentadienyltitanium substituted heteropolytungstates with Keggin structure,An[(CpTi)XW11O39]·xH2O(A=Me4N,K;X=P,Si,Co;Cp=η5-C5H5) were synthesized in aqueous phase.By allowing parent hete...Parent compounds of cyclopentadienyltitanium substituted heteropolytungstates with Keggin structure,An[(CpTi)XW11O39]·xH2O(A=Me4N,K;X=P,Si,Co;Cp=η5-C5H5) were synthesized in aqueous phase.By allowing parent heteropoly compounds to react with protonated 8-quinolinol,the title supermolecular compounds(C9H8NO)mAn[(CpTi)XW11O39]·xH2O(A=Me4N,H;X=P,Si,Co) were synthesized.The title compounds were characterized by means of elementary analysis,IR,UV,1H NMR,XRD and TG-DSC.The results indicate that the title compounds are new heteropoly compounds,and there is a charge transfer interaction between the organic cation and heteropoly anion.The results obtained from thermal analysis show that QCpTiPW,QCpTiSiW and QCpTiCoW begin to decompose at 212.4,194.2 and 171.2 ℃,respectively.The results obtained from antibacterial test reveal that QCpTiSiW has the best antibacterial activity,and the MIC values of QCpTiSiW against Escherichia coli and Staphylococcus aurous are 64.0 and 0.500 μg·mL-1,respectively.展开更多
Keggin type heteropolyacids was found to be an efficient and reusable catalyst for the synthesis of biologically active quinoxaline derivatives from the condensation of 1,2-diamine with 1,2-dicarbonyl compounds in exc...Keggin type heteropolyacids was found to be an efficient and reusable catalyst for the synthesis of biologically active quinoxaline derivatives from the condensation of 1,2-diamine with 1,2-dicarbonyl compounds in excellent yields in water. This method provides a new and efficient protocol in terms of small quantity of catalyst, a wide scope of substrates, and simple work-up procedure.展开更多
The fascinating chemical structure and broad application prospect of Keggin-type polyoxometalates(POMs)have attracted many chemists to explore and discover continuously.Unlike the traditional Keggin,larger metal atomi...The fascinating chemical structure and broad application prospect of Keggin-type polyoxometalates(POMs)have attracted many chemists to explore and discover continuously.Unlike the traditional Keggin,larger metal atomic radius,higher metal coordinated numbers,lower metal valence states and other features allow the group IVB metal-based Keggin(IVB-Keggin)more space and unknown in terms of structure and performance.Herein,density functional theory(DFT)calculations were performed to explore the influences including cores,shells,caps,and terminal ligands,et al.on IVB-Keggin,and analyze the possibility of novel structure synthesis.From the perspective of multi-layer onion-like clusters,molecular energy level,host-guest interaction energy,surface charge and covalent bond polarity can be further adjusted to achieve the oriented design of functional IVB-Keggin.These insights are expected to provide theoretical support for experimental synthesis,opening a new perspective to understand the growth of Keggin.展开更多
Mixed ammonium-transition metal salts with formula of （NH4）xMyHzPMo12O40 （M = Ni^2＋, Co^2＋ or Fe ^3＋） denoted as MPMo12 have been investigated for the oxidation of propane, with molecular oxygen, at temperature...Mixed ammonium-transition metal salts with formula of （NH4）xMyHzPMo12O40 （M = Ni^2＋, Co^2＋ or Fe ^3＋） denoted as MPMo12 have been investigated for the oxidation of propane, with molecular oxygen, at temperature range between 380 ℃ and 420 ℃ after in-situ pre-treatment performed at two heating rate of 5 or 9℃/min. They were characterized by BET method, XRD, UV-Vis and IR techniques. The catalysts were found to be active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-treated with the heating rate of 9℃/min. FePMo12 was found to be a more active catalyst for propene （17.2% yield） with minimal over deep oxidation （0.3% yield in COx）.展开更多
We have systematically studied redox properties of two series of several dozen heteropoly acids (salts) and their derivatives with vanadium and rare-earth elements with Keggin and Dawson structures, e. g. LnHSiMo_(12)...We have systematically studied redox properties of two series of several dozen heteropoly acids (salts) and their derivatives with vanadium and rare-earth elements with Keggin and Dawson structures, e. g. LnHSiMo_(12), SiMo_(12-n)V_n, M_(1.5)PMo_(12), PMo_(12-n)V_n, PW_(12-n_V_n, Ln(PMo_(11))_2, Sm(XMo_(11))_2 and P_2Mo_(18-n)V_n, etc., and obtained their sequence of oxidation. It was found that there is a linear relationship between the reduction potentials of heteropoly anions and the derivatives of heteropoly anions with rare-earth elements with Keggin structure and nq^2 (n and q are the principal quantum number and charge of the central ion respectively). On the basis of the electrostatic model the regularity of oxidation and reduction was rationalized.展开更多
Secondary amine based ionic liquid and defective Keggin type heteropoly acid (HPA) are separately used for efficient one-pot four-component synthesis of 1,2,4,5-tetrasubstituted imidazoles assisted by microwave (MW). ...Secondary amine based ionic liquid and defective Keggin type heteropoly acid (HPA) are separately used for efficient one-pot four-component synthesis of 1,2,4,5-tetrasubstituted imidazoles assisted by microwave (MW). Eco-friendly solvent free procedure, short reaction time, high yield of products and reusability of catalysts are important features of the synthesis. A comparative study on the efficiency of the two catalysts is reported. This work further demonstrates the alternate use of urea, instead of often used ammonium acetate, as source of nitrogen.展开更多
Coagulation-based pre-treatment efficiency of high strength digestate of food waste(HSDFW) anaerobic digestion is negated by organic ligand-catalyzed decomposition of coagulants. In this study, an efficient HSDFW pre-...Coagulation-based pre-treatment efficiency of high strength digestate of food waste(HSDFW) anaerobic digestion is negated by organic ligand-catalyzed decomposition of coagulants. In this study, an efficient HSDFW pre-treatment method, magnetic seeds(MS) coagulation, was employed by using highly stable Keggin Al_(30) nanocluster(PAC_(30)), MS and polyacrylamide(PAM), and its operation was optimized by evaluating the performance of removing turbidity, total suspended solids(TSS), chemical oxygen demand(COD), and total phosphorous(TP) phosphate. Results showed that at the optimum dosage of 4.82 g/L, PAC_(30) demonstrated excellent removals as high as 98.93% ± 0.1% of turbidity, 98.04% ± 0.1% of TSS, 58.28% ± 0.3% of total COD, 99.98% ± 0.01% of TP and 99.50% ± 0.01% of dissolved phosphate, respectively. Apparent molecular weight(AMW) and three-dimensional excitation-emission matrix(3 D-EEM) fluorescence spectroscopy analyses demonstrated more efficient removal of dissolved organic matter(DOM), particularly non-biodegradable and hydrophobic components by PAC_(30) than commercial coagulant. The sedimentation was much improved from 40 min by coagulation/flocculation to about 5 min settling by MS coagulation. The PAC_(30) based magnetic coagulation(MC) presents theoretical guidance on a cost-effective and much less footprint pre-treatment alternative for high strength wastewater.展开更多
The redox properties of molybdovanadoarsenic heteropolyacids having keggin structure,H x[AsV nM O 12-n O 40 ]·YH 2O(n=1～4),were studied with polarography,cyclic voltammetry and XPS.It was ascertained that three ...The redox properties of molybdovanadoarsenic heteropolyacids having keggin structure,H x[AsV nM O 12-n O 40 ]·YH 2O(n=1～4),were studied with polarography,cyclic voltammetry and XPS.It was ascertained that three redution steps for the four heteropolyacids involved 2,2,2 electrons accompanied by the adition of 1,1,1 protons.A reduction mechanism has been proposed.The oxidation ability of these heteropolyacids increases with the increase of the substitution of vanadium.展开更多
A cobalt paradodecatungstate [Co（H2O）5]2[Co（H2O）4]3[H2W12O42]·11H2O has been successfully synthesized and structurally characterized by X-ray crystallography. Structure analysis indicates that the title compo...A cobalt paradodecatungstate [Co（H2O）5]2[Co（H2O）4]3[H2W12O42]·11H2O has been successfully synthesized and structurally characterized by X-ray crystallography. Structure analysis indicates that the title compound is of monoclinic, space group P21/n, with a = 13.449（3）, b = 19.585（4）, c = 13.990（3） °A, = 113.79（3）°, V = 3371.8（12） °A^3, Z = 2, R = 0.0519 and wR = 0.1242. The title compound exhibits a novel 3D extended network structure constructed by interconnecting the paradodecatungstate polyanion [H2W12O42]^10- clusters and cobalt^11 coordination ions.展开更多
A 3D infinitely extended structural rare earth coordination compound with a formula of K3{[Sm(H2O)7]2Na[a-SiW11O39Sm(H2O)4]2}·14H2O has been synthesized by reaction of Sm2O3,HClO4,NaOH with a-K8SiW11O39·nH2O...A 3D infinitely extended structural rare earth coordination compound with a formula of K3{[Sm(H2O)7]2Na[a-SiW11O39Sm(H2O)4]2}·14H2O has been synthesized by reaction of Sm2O3,HClO4,NaOH with a-K8SiW11O39·nH2O,and characterized by IR,UV spectra,ICP,TG-DTA,cyclic voltammetry,variable-temperature magnetic susceptibility and X-ray single-crystal diffrac-tion.X-ray single-crystal diffraction indicates that the title compound crystallizes in a triclinic lat-tice,Pi space group,with a = 1.2462(3) nm,b = 1.2652(3) nm,c = 1.8420(4) nm,α = 87.45(3)°,β = 79.91(3)°,γ = 82.57(3)°,Z = 1,R1 = 0.0778,wR2 = 0.1610.Structural analysis reveals that Sm3+(1) coordination cation has incorporated into the vacant site of [α-SiW11O39]8? entity,forming the [α-SiW11O39Sm(H2O)4]5? subunit.The two adjacent [a-SiW11O39Sm(H2O)4]5? subunits are combined with each other through two Sm(1)-O-W bridges accompanying the formation of dim-mer structural unit [α-SiW11O39Sm(H2O)4]210? of the title compound.The neighboring dimmer structural units [α-SiW11O39Sm(H2O)4]210? are linked to form the 1D chainlike structure by means of two Sm3+(2) and a Na+(1) coordination cations.The K+(1) cations connect the 1D packing chains constructing the 2D netlike structure,and adjacent netlike layers are also grafted by K+(2) cations to build the novel 3D infinitely extended structure.The result of TG-DTA curves manifests that the decomposition temperature of the title polyanionic framework is 554℃.The cyclic volt-ammetry measurements show that the title polyanion has the two-step redox processes in aqueous solution with pH = 3.1.Variable temperature magnetic susceptibility indicates the title compound obeys the Cruie-Weiss Law in the higher temperature range from 110 to 300 K,while in the lower temperature range from 2 to 110 K the comparatively strong antiferromagnetism in-teractions can be observed.展开更多
Various type of cesium partially substituted phosphotungstate,Cs_xH_（3-x）PW_（12）O_（40）（x = 1.0,2.0 and 2.5）,were synthesized and their catalytic activities were investigated in the synthesis of quinoline.It wa...Various type of cesium partially substituted phosphotungstate,Cs_xH_（3-x）PW_（12）O_（40）（x = 1.0,2.0 and 2.5）,were synthesized and their catalytic activities were investigated in the synthesis of quinoline.It was shown that catalytic activities of these catalysts correlated to surface acidity and total number of acidic sites.Finally,a series of quinoline derivatives were synthesized with Cs2.5H0.5PW12O40 via the Friedlander reaction in high to excellent yields and the plausible mechanism was proposed.Simple experiment,catalyst reusability,short reaction time and preclusion of toxic solvent are the advantages of this method.展开更多
基金Supported by the National Nature Science Foundation of China(No.21476177)
文摘A serial of ordered meso-macroporous phosphotungstic acid(HPW) supported on SiO2 nanocomposites were successfully prepared by a homogeneous precipitation method, using monodispersed polystyrene(PS) microspheres and cationic surfactant as structure directing agent. These nanocomposites were used as catalysts for oxidative desulfurization(ODS) of model fuel. The materials were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), N2 adsorption-desorption isothrem, X-ray diffraction(XRD), and Fourier transform infrared spectra(FTIR). The characterization results suggested that the as-prepared material possessed ordered meso-macroporous architectures with Keggin type phosphotungstic acid dispersed homogeneously in SiO2 matrix. Under the selected reaction conditions, dibenzothiophene(DBT) in model fuel can be removed within 2 h at room temperature(30 ℃). In addition, only 1.2% of efficiency lose than the fresh catalyst even after 5 cycles.
基金the Deanship of Scientific Research at King Saud University for funding the work through the research group project (No. RGP-VPP-116)
文摘Direct synthesis of dimethyl carbonate （DMC） from methanol and carbon dioxide over Co1.5PW12O40 in liquid and in gas phase is investigated. The synthesized catalyst has been characterized by means of FTIR and XRD. Liquid phase experiment results showed that high pressures are favorable for the synthesis of DMC. However, DMC formation is limited by the reaction with co-produced water. DMC selectivity is more strongly dependent on the temperature than on the pressure of CO2. As for the reactions in gas phase, it has been found that both CH3OH conversion and DMC selectivity decreased with increasing temperature, owing to the decomposition of DMC at high temperatures. High temperatures and more amount of Co1.5PW12O40 catalyst favor the formation of dimethoxymethane （DMM） and methyl formate （MF）.
基金supported by the chemical materials institute China academy of engineering physics,the doctoral innovation research assistance program of science and technology review
文摘Parent compounds of cyclopentadienyltitanium substituted heteropolytungstates with Keggin structure,An[(CpTi)XW11O39]·xH2O(A=Me4N,K;X=P,Si,Co;Cp=η5-C5H5) were synthesized in aqueous phase.By allowing parent heteropoly compounds to react with protonated 8-quinolinol,the title supermolecular compounds(C9H8NO)mAn[(CpTi)XW11O39]·xH2O(A=Me4N,H;X=P,Si,Co) were synthesized.The title compounds were characterized by means of elementary analysis,IR,UV,1H NMR,XRD and TG-DSC.The results indicate that the title compounds are new heteropoly compounds,and there is a charge transfer interaction between the organic cation and heteropoly anion.The results obtained from thermal analysis show that QCpTiPW,QCpTiSiW and QCpTiCoW begin to decompose at 212.4,194.2 and 171.2 ℃,respectively.The results obtained from antibacterial test reveal that QCpTiSiW has the best antibacterial activity,and the MIC values of QCpTiSiW against Escherichia coli and Staphylococcus aurous are 64.0 and 0.500 μg·mL-1,respectively.
文摘Keggin type heteropolyacids was found to be an efficient and reusable catalyst for the synthesis of biologically active quinoxaline derivatives from the condensation of 1,2-diamine with 1,2-dicarbonyl compounds in excellent yields in water. This method provides a new and efficient protocol in terms of small quantity of catalyst, a wide scope of substrates, and simple work-up procedure.
基金financially supported by the National Natural Science Foundation of China(NSFC,Nos.22225109,22071109,92061101,22173016 and 22301084)the China Postdoctoral Science Foundation(No.2023M741232)。
文摘The fascinating chemical structure and broad application prospect of Keggin-type polyoxometalates(POMs)have attracted many chemists to explore and discover continuously.Unlike the traditional Keggin,larger metal atomic radius,higher metal coordinated numbers,lower metal valence states and other features allow the group IVB metal-based Keggin(IVB-Keggin)more space and unknown in terms of structure and performance.Herein,density functional theory(DFT)calculations were performed to explore the influences including cores,shells,caps,and terminal ligands,et al.on IVB-Keggin,and analyze the possibility of novel structure synthesis.From the perspective of multi-layer onion-like clusters,molecular energy level,host-guest interaction energy,surface charge and covalent bond polarity can be further adjusted to achieve the oriented design of functional IVB-Keggin.These insights are expected to provide theoretical support for experimental synthesis,opening a new perspective to understand the growth of Keggin.
文摘Mixed ammonium-transition metal salts with formula of （NH4）xMyHzPMo12O40 （M = Ni^2＋, Co^2＋ or Fe ^3＋） denoted as MPMo12 have been investigated for the oxidation of propane, with molecular oxygen, at temperature range between 380 ℃ and 420 ℃ after in-situ pre-treatment performed at two heating rate of 5 or 9℃/min. They were characterized by BET method, XRD, UV-Vis and IR techniques. The catalysts were found to be active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-treated with the heating rate of 9℃/min. FePMo12 was found to be a more active catalyst for propene （17.2% yield） with minimal over deep oxidation （0.3% yield in COx）.
基金Project supported by the National Natural Science Foundation of China.
文摘We have systematically studied redox properties of two series of several dozen heteropoly acids (salts) and their derivatives with vanadium and rare-earth elements with Keggin and Dawson structures, e. g. LnHSiMo_(12), SiMo_(12-n)V_n, M_(1.5)PMo_(12), PMo_(12-n)V_n, PW_(12-n_V_n, Ln(PMo_(11))_2, Sm(XMo_(11))_2 and P_2Mo_(18-n)V_n, etc., and obtained their sequence of oxidation. It was found that there is a linear relationship between the reduction potentials of heteropoly anions and the derivatives of heteropoly anions with rare-earth elements with Keggin structure and nq^2 (n and q are the principal quantum number and charge of the central ion respectively). On the basis of the electrostatic model the regularity of oxidation and reduction was rationalized.
文摘Secondary amine based ionic liquid and defective Keggin type heteropoly acid (HPA) are separately used for efficient one-pot four-component synthesis of 1,2,4,5-tetrasubstituted imidazoles assisted by microwave (MW). Eco-friendly solvent free procedure, short reaction time, high yield of products and reusability of catalysts are important features of the synthesis. A comparative study on the efficiency of the two catalysts is reported. This work further demonstrates the alternate use of urea, instead of often used ammonium acetate, as source of nitrogen.
基金supported by the National Key Research and Development Program of China (No. 2018YFD1100600)the Program of China-Sri Lanka Joint Center for Water Technology Research and Demonstrationthe Chinese Government Scholarship Program (CSC No. 2018SLJ023250)。
文摘Coagulation-based pre-treatment efficiency of high strength digestate of food waste(HSDFW) anaerobic digestion is negated by organic ligand-catalyzed decomposition of coagulants. In this study, an efficient HSDFW pre-treatment method, magnetic seeds(MS) coagulation, was employed by using highly stable Keggin Al_(30) nanocluster(PAC_(30)), MS and polyacrylamide(PAM), and its operation was optimized by evaluating the performance of removing turbidity, total suspended solids(TSS), chemical oxygen demand(COD), and total phosphorous(TP) phosphate. Results showed that at the optimum dosage of 4.82 g/L, PAC_(30) demonstrated excellent removals as high as 98.93% ± 0.1% of turbidity, 98.04% ± 0.1% of TSS, 58.28% ± 0.3% of total COD, 99.98% ± 0.01% of TP and 99.50% ± 0.01% of dissolved phosphate, respectively. Apparent molecular weight(AMW) and three-dimensional excitation-emission matrix(3 D-EEM) fluorescence spectroscopy analyses demonstrated more efficient removal of dissolved organic matter(DOM), particularly non-biodegradable and hydrophobic components by PAC_(30) than commercial coagulant. The sedimentation was much improved from 40 min by coagulation/flocculation to about 5 min settling by MS coagulation. The PAC_(30) based magnetic coagulation(MC) presents theoretical guidance on a cost-effective and much less footprint pre-treatment alternative for high strength wastewater.
文摘The redox properties of molybdovanadoarsenic heteropolyacids having keggin structure,H x[AsV nM O 12-n O 40 ]·YH 2O(n=1～4),were studied with polarography,cyclic voltammetry and XPS.It was ascertained that three redution steps for the four heteropolyacids involved 2,2,2 electrons accompanied by the adition of 1,1,1 protons.A reduction mechanism has been proposed.The oxidation ability of these heteropolyacids increases with the increase of the substitution of vanadium.
基金This work was supported by the National Natural Science Foundation of China, Specialized Research Fund for the Doctoral Program of Higher Education, Henan Innovation Project for University Prominent Research Talents, Program for New Century Excellent Talent in University of Henan Province, the Foundation of Educational Department of Henan Province and Natural Science Foundation of Henan Province
文摘A cobalt paradodecatungstate [Co（H2O）5]2[Co（H2O）4]3[H2W12O42]·11H2O has been successfully synthesized and structurally characterized by X-ray crystallography. Structure analysis indicates that the title compound is of monoclinic, space group P21/n, with a = 13.449（3）, b = 19.585（4）, c = 13.990（3） °A, = 113.79（3）°, V = 3371.8（12） °A^3, Z = 2, R = 0.0519 and wR = 0.1242. The title compound exhibits a novel 3D extended network structure constructed by interconnecting the paradodecatungstate polyanion [H2W12O42]^10- clusters and cobalt^11 coordination ions.
文摘A 3D infinitely extended structural rare earth coordination compound with a formula of K3{[Sm(H2O)7]2Na[a-SiW11O39Sm(H2O)4]2}·14H2O has been synthesized by reaction of Sm2O3,HClO4,NaOH with a-K8SiW11O39·nH2O,and characterized by IR,UV spectra,ICP,TG-DTA,cyclic voltammetry,variable-temperature magnetic susceptibility and X-ray single-crystal diffrac-tion.X-ray single-crystal diffraction indicates that the title compound crystallizes in a triclinic lat-tice,Pi space group,with a = 1.2462(3) nm,b = 1.2652(3) nm,c = 1.8420(4) nm,α = 87.45(3)°,β = 79.91(3)°,γ = 82.57(3)°,Z = 1,R1 = 0.0778,wR2 = 0.1610.Structural analysis reveals that Sm3+(1) coordination cation has incorporated into the vacant site of [α-SiW11O39]8? entity,forming the [α-SiW11O39Sm(H2O)4]5? subunit.The two adjacent [a-SiW11O39Sm(H2O)4]5? subunits are combined with each other through two Sm(1)-O-W bridges accompanying the formation of dim-mer structural unit [α-SiW11O39Sm(H2O)4]210? of the title compound.The neighboring dimmer structural units [α-SiW11O39Sm(H2O)4]210? are linked to form the 1D chainlike structure by means of two Sm3+(2) and a Na+(1) coordination cations.The K+(1) cations connect the 1D packing chains constructing the 2D netlike structure,and adjacent netlike layers are also grafted by K+(2) cations to build the novel 3D infinitely extended structure.The result of TG-DTA curves manifests that the decomposition temperature of the title polyanionic framework is 554℃.The cyclic volt-ammetry measurements show that the title polyanion has the two-step redox processes in aqueous solution with pH = 3.1.Variable temperature magnetic susceptibility indicates the title compound obeys the Cruie-Weiss Law in the higher temperature range from 110 to 300 K,while in the lower temperature range from 2 to 110 K the comparatively strong antiferromagnetism in-teractions can be observed.
基金the Razi University Research Council and Kermanshah Oil Refining Company
文摘Various type of cesium partially substituted phosphotungstate,Cs_xH_（3-x）PW_（12）O_（40）（x = 1.0,2.0 and 2.5）,were synthesized and their catalytic activities were investigated in the synthesis of quinoline.It was shown that catalytic activities of these catalysts correlated to surface acidity and total number of acidic sites.Finally,a series of quinoline derivatives were synthesized with Cs2.5H0.5PW12O40 via the Friedlander reaction in high to excellent yields and the plausible mechanism was proposed.Simple experiment,catalyst reusability,short reaction time and preclusion of toxic solvent are the advantages of this method.
