A new polyoxometalate dimer based on lacunary Wells-Dawson anion and lanthanide cation, Na14[{Nd（H2O）3 （α2-PeWt7O61）2]·17H2O, was isolated as a sodium salt under ambient conditions and characterized by IR, T...A new polyoxometalate dimer based on lacunary Wells-Dawson anion and lanthanide cation, Na14[{Nd（H2O）3 （α2-PeWt7O61）2]·17H2O, was isolated as a sodium salt under ambient conditions and characterized by IR, TG, and X-ray single crystal structure analysis and electrochemistry. It belonged to the triclinic, space group Pi with a=1.26738 （15） nm, b=1.41464 （17） nm, c=2.3254 （4） nm, α=103.142 （2）°, β = 95.122 （2）°, γ=113.9690 （10）°, V=3.6317 （8）nm^3, Z=2, Dc=4.274 mg/m^3, and μ=27.695 mm^-1. The Nd^3＋ ion was substituted for a [W=O]^4＋ unit in the ＂cap＂ site of the tungsten-oxygen framework of the parent Wells-Dawson ion. The cyclic voltammograms of the title compound exhibited nearly chemically reversible one-step one-electron transfer process and two-step irreversible reduction processes. Thermogravimetric showed a one-step slow weight loss stage in the range of 25-850 ℃.展开更多
A novel cerium(Ⅲ) salt of Dawson type tungstophosphoric acid(Ce2P2W18O62·16H2O) was prepared by doping cerous nitrate in H6P2W18O62·13H2O powder and characterized by thermogravimetry and differential therma...A novel cerium(Ⅲ) salt of Dawson type tungstophosphoric acid(Ce2P2W18O62·16H2O) was prepared by doping cerous nitrate in H6P2W18O62·13H2O powder and characterized by thermogravimetry and differential thermal analyses(TG/DTA),Fourier transform infrared spectroscopy(FT-IR),X-ray powder diffraction(XRD),pyridine infrared spectroscopy(Py-IR) and scanning electron microscopy(SEM).Its catalytic activity was evaluated by the probe reaction of synthesis of n-butyl acetate with acetic acid and n-butanol.The effects of various parameters such as molar ratio of n-butanol to acetic acid,reaction temperature,reaction time,and catalyst amount have been studied by single factor experiment.The results show that Ce2P2W18O62·16H2O behaved as an excellent heterogeneous catalyst in the synthesis of n-butyl acetate.The optimum synthetic conditions were determined as follows︰molar ratio of n-butanol to acetic acid at 2.0︰1.0,mass of the catalyst being 1.44% of the total reaction mixture,reaction temperature of 120 ℃ and reaction time of 150 min.Under above conditions,the conversion of acetic acid was above 97.8%.The selectivity of n-butyl acetate based on acetic acid was,in all cases,nearly 100%.The catalysts could be recycled and still exhibited high catalytic activity with 90.4% conversion after five cycles of reaction.It was found by means of TG-DTA and Py-IR that the catalyst deactivation was due to the adsorption of a complex of by-product on the active sites on catalysts surface or the catalyst loss in its separation from the products.Compared with using sulfuric acid as catalyst,the present procedure with Ce2P2W18O62·16H2O is a green productive technology due to simple process,higher yield,catalyst recycling and no corrosion for the production facilities.展开更多
Zn2Al layered double hydroxide pillared with Dawson polyoxometalates,P2W17ZO8-61(Z=Mn2+,Co2+,Ni2+,Cu2+,Zn2+)was prepared.A basal space ofca.16 nm indicates the intercalated Dawson ions to be oriented with their C2 axi...Zn2Al layered double hydroxide pillared with Dawson polyoxometalates,P2W17ZO8-61(Z=Mn2+,Co2+,Ni2+,Cu2+,Zn2+)was prepared.A basal space ofca.16 nm indicates the intercalated Dawson ions to be oriented with their C2 axis perpendicular to the double hydroxide layers(with the exception of P2W17ZnLDH).The IR and^(13)P MASNMR spectral reveal that the Dawson ions retain their integrity in the interlayer space of LDH.A preliminary study shows that these compounds are highly active catalysts for the oxidation of cyclohexene with molecular oxygen.展开更多
An unprecedented 1D zigzag chain alkaline earth metal derivative, {[Ba（DMF）3 （H20）2][Ba（DMF）412（P2W18O62）}n, （DMF=N, N-dimethyl formamide） containing Dawson hetero- polyanion has been successfully synthesize...An unprecedented 1D zigzag chain alkaline earth metal derivative, {[Ba（DMF）3 （H20）2][Ba（DMF）412（P2W18O62）}n, （DMF=N, N-dimethyl formamide） containing Dawson hetero- polyanion has been successfully synthesized and characterized by X-ray crystallography. Two barium cations bridged by three DMF ligands in parallel combination with the Dawson-type heteropolyanion [P2W18O62]^6- and then the resulting subunits {[Ba（DMF）4]2（P2WlsO62）}^2＋ are alternately linked together via another [Ba（DMF）3（H2O）2]^2＋ ions, constructing a 1D zigzag chain architecture.展开更多
Two novel zeotype crystals, K4[Cr30（H2O） 3（OOCH） 6] 2[ P2W18O62]· 9.5H2 O and K4[ Cr3O（ H2O）3（ OOCH）6 ]2[ H3 P2 W17Co（H2O） O61]· 20H2O（2） , were synthesized and their structures were determined ...Two novel zeotype crystals, K4[Cr30（H2O） 3（OOCH） 6] 2[ P2W18O62]· 9.5H2 O and K4[ Cr3O（ H2O）3（ OOCH）6 ]2[ H3 P2 W17Co（H2O） O61]· 20H2O（2） , were synthesized and their structures were determined using X-ray single crystal diffraction. Crystal data： C12H43O103.5K4Cr6P2W18（1）, hexagonal P6（3）/m, α= 1. 5895（2） nm, b=1.5895（2） nm, c =2.1620（4） nm, α=90°, β=90°, γ= 120°, V=4.7305（13） nm^3, Z=2, R1 =0,0726, ωR2 =0. 1542; C6H57O98K4Cr3CoP2W17 （2）, hexagonal P6（3）/mmc, α = 1.61328（3） nm, b = 1.61328（3） nm, c=2.06613（9） nm, α=90°, β=90°, γ=120°, V=4.6570（2） nm^3, Z=2, R1 =0.0377, ωR2 =0. 1070. These crystals were characterized using elemental analysis, IR, TG-DTA, and XRD. It was found that the polyoxometalate anions maintained Wells-Dawson structure for crystal I and laeunary Wens-Dawson structure for crystal 2. Thermal analysis showed that crystal 1 lost the water of crystallization at 132 ℃, whereas crystal 2 lost the water of crystallization at 100 ℃. Crystal 1 could reversibly desorb and adsorb water molecules and its crystal structure could be restored after re-adsorbing the water molecules. It was also found from the XRD patterns that the void size of crystal 2 is smaller compared with that of crystal 1, which is attributed to the higher anion charges.展开更多
The present paper covers a salt of 2:18 heteropoly complex of tungstotitanophosphate prepared with the method of improved sequence preparation. The title compound was characterized by elemental analysis, 31P NMR spect...The present paper covers a salt of 2:18 heteropoly complex of tungstotitanophosphate prepared with the method of improved sequence preparation. The title compound was characterized by elemental analysis, 31P NMR spectra, polarography, cyclic voltammetry, IR, UV, X-ray powder diffraction , X-ray photoelectron spectra and TG-DTA analysis. The results show that the complex with the formula K8[TiP2W17O62]·12H2O has Dawson structure. Its properties such as spectra, redox behavior and thermal stability are discussed.展开更多
Eleven heteropolytungstophosphate compounds with lanthanon having Dawson structure were prepared, Ln_2[P_2W_(18)O_(62)]·xH_2O(Ln=La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Yb).Their structures were studied by IR,UV,polarograp...Eleven heteropolytungstophosphate compounds with lanthanon having Dawson structure were prepared, Ln_2[P_2W_(18)O_(62)]·xH_2O(Ln=La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Yb).Their structures were studied by IR,UV,polarography ,X-ray diffraction and X-ray photoelectron spectroscopy.展开更多
A series of lanthanide complexes.K17 [Ln (As2W17O61)2].rH2O (Ln=La, Pr,Nd, Sm, Eu,.Gd or Dy) have been prepared and characterized by elemental analysis,IR.183W NMR and electrochemistry.
Tetrabutylammonium or potassium salts of organometalllic derivatives of lacunary polyanion (RM) 3P 2W 15 O n- 59 (RM=CpTi, CpZr, C 4H 7O 2Sn or C 5H 9O 2Sn) have been prepared and structurally...Tetrabutylammonium or potassium salts of organometalllic derivatives of lacunary polyanion (RM) 3P 2W 15 O n- 59 (RM=CpTi, CpZr, C 4H 7O 2Sn or C 5H 9O 2Sn) have been prepared and structurally characterized by elemental analysis, IR, UV vis, 1H NMR and 183 W NMR spectroscopies. The title complexes exhibit antitumor activity in vitro.展开更多
基金the Nature Science Foundation of Henan Province (0611011900)
文摘A new polyoxometalate dimer based on lacunary Wells-Dawson anion and lanthanide cation, Na14[{Nd（H2O）3 （α2-PeWt7O61）2]·17H2O, was isolated as a sodium salt under ambient conditions and characterized by IR, TG, and X-ray single crystal structure analysis and electrochemistry. It belonged to the triclinic, space group Pi with a=1.26738 （15） nm, b=1.41464 （17） nm, c=2.3254 （4） nm, α=103.142 （2）°, β = 95.122 （2）°, γ=113.9690 （10）°, V=3.6317 （8）nm^3, Z=2, Dc=4.274 mg/m^3, and μ=27.695 mm^-1. The Nd^3＋ ion was substituted for a [W=O]^4＋ unit in the ＂cap＂ site of the tungsten-oxygen framework of the parent Wells-Dawson ion. The cyclic voltammograms of the title compound exhibited nearly chemically reversible one-step one-electron transfer process and two-step irreversible reduction processes. Thermogravimetric showed a one-step slow weight loss stage in the range of 25-850 ℃.
基金Supported by the National Natural Science Foundation of China（21161009）the Natural Science Foundation of Jiangxi Province（20122BAB213001,20114BAB213002）the Science and Technology Foundation of Jiangxi Province（GJJ11613）
文摘A novel cerium(Ⅲ) salt of Dawson type tungstophosphoric acid(Ce2P2W18O62·16H2O) was prepared by doping cerous nitrate in H6P2W18O62·13H2O powder and characterized by thermogravimetry and differential thermal analyses(TG/DTA),Fourier transform infrared spectroscopy(FT-IR),X-ray powder diffraction(XRD),pyridine infrared spectroscopy(Py-IR) and scanning electron microscopy(SEM).Its catalytic activity was evaluated by the probe reaction of synthesis of n-butyl acetate with acetic acid and n-butanol.The effects of various parameters such as molar ratio of n-butanol to acetic acid,reaction temperature,reaction time,and catalyst amount have been studied by single factor experiment.The results show that Ce2P2W18O62·16H2O behaved as an excellent heterogeneous catalyst in the synthesis of n-butyl acetate.The optimum synthetic conditions were determined as follows︰molar ratio of n-butanol to acetic acid at 2.0︰1.0,mass of the catalyst being 1.44% of the total reaction mixture,reaction temperature of 120 ℃ and reaction time of 150 min.Under above conditions,the conversion of acetic acid was above 97.8%.The selectivity of n-butyl acetate based on acetic acid was,in all cases,nearly 100%.The catalysts could be recycled and still exhibited high catalytic activity with 90.4% conversion after five cycles of reaction.It was found by means of TG-DTA and Py-IR that the catalyst deactivation was due to the adsorption of a complex of by-product on the active sites on catalysts surface or the catalyst loss in its separation from the products.Compared with using sulfuric acid as catalyst,the present procedure with Ce2P2W18O62·16H2O is a green productive technology due to simple process,higher yield,catalyst recycling and no corrosion for the production facilities.
文摘Zn2Al layered double hydroxide pillared with Dawson polyoxometalates,P2W17ZO8-61(Z=Mn2+,Co2+,Ni2+,Cu2+,Zn2+)was prepared.A basal space ofca.16 nm indicates the intercalated Dawson ions to be oriented with their C2 axis perpendicular to the double hydroxide layers(with the exception of P2W17ZnLDH).The IR and^(13)P MASNMR spectral reveal that the Dawson ions retain their integrity in the interlayer space of LDH.A preliminary study shows that these compounds are highly active catalysts for the oxidation of cyclohexene with molecular oxygen.
文摘An unprecedented 1D zigzag chain alkaline earth metal derivative, {[Ba（DMF）3 （H20）2][Ba（DMF）412（P2W18O62）}n, （DMF=N, N-dimethyl formamide） containing Dawson hetero- polyanion has been successfully synthesized and characterized by X-ray crystallography. Two barium cations bridged by three DMF ligands in parallel combination with the Dawson-type heteropolyanion [P2W18O62]^6- and then the resulting subunits {[Ba（DMF）4]2（P2WlsO62）}^2＋ are alternately linked together via another [Ba（DMF）3（H2O）2]^2＋ ions, constructing a 1D zigzag chain architecture.
基金Supported by the Dalian Municipal Science and Technology Commission and Liaoning Provincial Science and Technology Com-mission(No. 20031059)
文摘Two novel zeotype crystals, K4[Cr30（H2O） 3（OOCH） 6] 2[ P2W18O62]· 9.5H2 O and K4[ Cr3O（ H2O）3（ OOCH）6 ]2[ H3 P2 W17Co（H2O） O61]· 20H2O（2） , were synthesized and their structures were determined using X-ray single crystal diffraction. Crystal data： C12H43O103.5K4Cr6P2W18（1）, hexagonal P6（3）/m, α= 1. 5895（2） nm, b=1.5895（2） nm, c =2.1620（4） nm, α=90°, β=90°, γ= 120°, V=4.7305（13） nm^3, Z=2, R1 =0,0726, ωR2 =0. 1542; C6H57O98K4Cr3CoP2W17 （2）, hexagonal P6（3）/mmc, α = 1.61328（3） nm, b = 1.61328（3） nm, c=2.06613（9） nm, α=90°, β=90°, γ=120°, V=4.6570（2） nm^3, Z=2, R1 =0.0377, ωR2 =0. 1070. These crystals were characterized using elemental analysis, IR, TG-DTA, and XRD. It was found that the polyoxometalate anions maintained Wells-Dawson structure for crystal I and laeunary Wens-Dawson structure for crystal 2. Thermal analysis showed that crystal 1 lost the water of crystallization at 132 ℃, whereas crystal 2 lost the water of crystallization at 100 ℃. Crystal 1 could reversibly desorb and adsorb water molecules and its crystal structure could be restored after re-adsorbing the water molecules. It was also found from the XRD patterns that the void size of crystal 2 is smaller compared with that of crystal 1, which is attributed to the higher anion charges.
文摘The present paper covers a salt of 2:18 heteropoly complex of tungstotitanophosphate prepared with the method of improved sequence preparation. The title compound was characterized by elemental analysis, 31P NMR spectra, polarography, cyclic voltammetry, IR, UV, X-ray powder diffraction , X-ray photoelectron spectra and TG-DTA analysis. The results show that the complex with the formula K8[TiP2W17O62]·12H2O has Dawson structure. Its properties such as spectra, redox behavior and thermal stability are discussed.
文摘Eleven heteropolytungstophosphate compounds with lanthanon having Dawson structure were prepared, Ln_2[P_2W_(18)O_(62)]·xH_2O(Ln=La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Yb).Their structures were studied by IR,UV,polarography ,X-ray diffraction and X-ray photoelectron spectroscopy.
文摘A series of lanthanide complexes.K17 [Ln (As2W17O61)2].rH2O (Ln=La, Pr,Nd, Sm, Eu,.Gd or Dy) have been prepared and characterized by elemental analysis,IR.183W NMR and electrochemistry.
基金theNationalNaturalScienceFoundationofChina (No .2 0 1710 11)
文摘Tetrabutylammonium or potassium salts of organometalllic derivatives of lacunary polyanion (RM) 3P 2W 15 O n- 59 (RM=CpTi, CpZr, C 4H 7O 2Sn or C 5H 9O 2Sn) have been prepared and structurally characterized by elemental analysis, IR, UV vis, 1H NMR and 183 W NMR spectroscopies. The title complexes exhibit antitumor activity in vitro.
