The emission spectra of some heteropolytungstates containing europium, K.[Eu(XW11 O39)2](X = P, Ge, As, or Ga), K17[EuCAs2W17O61)2] and K16H9EuAs4W40O140 have been investigated and the structures of these compounds ar...The emission spectra of some heteropolytungstates containing europium, K.[Eu(XW11 O39)2](X = P, Ge, As, or Ga), K17[EuCAs2W17O61)2] and K16H9EuAs4W40O140 have been investigated and the structures of these compounds are discussed. The emission spectra at room temperature are very similar to each other in terms of both the number of bands and transition frequencies, showing that they have the similar structures to those of K16[Ce(P2W17O61)2] and K12[U(GeW11O39)2].展开更多
Three novel scandium-containing heteropolytungstates[Sc3(H2O)3NO(PW9O34)2]^10(1a)Scs(H2O)2(GeW6O34)2(GeW6O26)2]^12(2a)and[Sc11(W6O10)2(OH)2(H2O)16(BiW9O33)6]^27(3a)were synthesized by reactions of Sclllions with trila...Three novel scandium-containing heteropolytungstates[Sc3(H2O)3NO(PW9O34)2]^10(1a)Scs(H2O)2(GeW6O34)2(GeW6O26)2]^12(2a)and[Sc11(W6O10)2(OH)2(H2O)16(BiW9O33)6]^27(3a)were synthesized by reactions of Sclllions with trilacunary Keggin precursors,[A-a-XW9O34]^n(X=P,Ge,n=9,10)or[B-a-BiW9O33]^9,in NaOAc/HOAc buffer solution under conventional synthetic condition,respectively.All the three compounds were characterized by means of single-crystal X-ray diffraction(XRD),Fourier transform-infrared(FTIR)spectroscopy ultraviolet-visible(UV-Vis)spectroscopy,elemental analysis,and thermogravimetric analysis.The aqueous solutior stability of the sandwich polvanion[Sc3(H2O)3(pw9O34)2]^10-was also verified by electrospray ionization mass Spectrometry(ESI-MS)due to its good solubility in water.展开更多
A series of heteropolytungstates has been synthesized and utilized as catalysts to catalyze oxidation of benzyl alcohol with aqueous hydrogen peroxide. The results indicated that three of these catalysts showed the pr...A series of heteropolytungstates has been synthesized and utilized as catalysts to catalyze oxidation of benzyl alcohol with aqueous hydrogen peroxide. The results indicated that three of these catalysts showed the properties of reaction-controlled phasetransfer catalysis, and they had excellent catalytic ability to the oxidation of benzyl alcohol. No other by-products were detected by gas chromatography. Once the hydrogen peroxide was consumed completely, the catalyst precipitated from solvent, and the results of the catalyst recycle showed that the catalyst had high stability.展开更多
The Eu3+-doped Na24P2W22O83 has been prepared by solid state reaction, and characterized by element analysis, infrared spectroscopy, powder X-ray diffractometry. The emission and excitation spectra were measured. The ...The Eu3+-doped Na24P2W22O83 has been prepared by solid state reaction, and characterized by element analysis, infrared spectroscopy, powder X-ray diffractometry. The emission and excitation spectra were measured. The luminescence properties of Eu3+-doped Na24P2W22O83 and the energy transfer mechanism were discussed.展开更多
The complex Na10[LaSiW11O39(H2O)4]2?2H2O was synthesized and crystallized in monoclinic,space group P21/n with cell parameters: a=17.9786(9), b=23.5940(2), c=13.1289(8), β=90.141(2)°, V=5569.1(6)3, Mr=6336.60, Z...The complex Na10[LaSiW11O39(H2O)4]2?2H2O was synthesized and crystallized in monoclinic,space group P21/n with cell parameters: a=17.9786(9), b=23.5940(2), c=13.1289(8), β=90.141(2)°, V=5569.1(6)3, Mr=6336.60, Z=2, Dc=3.779g/cm3, (MoKa)= 0.71069? =23.533mm-1, F(000)=5488, T=293(2)K. The final refinement for 8404 observed reflections with I >2s (I) gave R = 0.0595 and wR = 0.1366. Both lanthanide cations are coordinated by nine oxygen atoms in a distorted squareantiprism environment. The LaO bond lengths are from 2.52(1) to 2.63(2).展开更多
A new heteropolytungstate, [H2bpy]3[SiMnW11O39]· 1.25H2O （1）, has been prepared under mild hydrothermal conditions and structurally characterized by single crystal X-ray diffraction. It is the first characteriz...A new heteropolytungstate, [H2bpy]3[SiMnW11O39]· 1.25H2O （1）, has been prepared under mild hydrothermal conditions and structurally characterized by single crystal X-ray diffraction. It is the first characterized compound containing ID zigzag chain of transition metal substituted Keggin heteropolytungstate, which is connected through a common oxygen atom. The elemental analysis and IR of it are also described.展开更多
The Eu^(3+)-doped Na^(24)As_2W_(22)O_83 phosphor has been prepared by solidstare reaction from Na_3AsO_4.12H_2O, Na_2WO_4.2H_2O and WO_3, and characterized by elementalanalysis, infrared spectroscopy and powder X-ray ...The Eu^(3+)-doped Na^(24)As_2W_(22)O_83 phosphor has been prepared by solidstare reaction from Na_3AsO_4.12H_2O, Na_2WO_4.2H_2O and WO_3, and characterized by elementalanalysis, infrared spectroscopy and powder X-ray diffractometry. According to the measurements withX-ray diffraction, this material belongs to orthorhombic system with its lattice constants: avelence 1.4750 nm, b velence 1.1944 nm, c velence 1.1062 nm, it is consistent with space groupD_2~4-P2_12_12_1 (No.19). The emission and excitation spectra were measured. The luminescentproperties of Eu^(3+)-doped Na^(24)As_2W_(22)O_83 and mechanism of energy transfer were discussed.展开更多
The redox properties of K17[Ln(As2W17O61)2](Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Tm or Yb) in solution were investigated using polarographic and cyclic voltammographic methods. Experimental results indicate that t...The redox properties of K17[Ln(As2W17O61)2](Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Tm or Yb) in solution were investigated using polarographic and cyclic voltammographic methods. Experimental results indicate that the heteropolyanions underwent three-step-two-electron-tungsten-reduction processes, and each reduction process was accompanied by adding two protons.展开更多
The heteropolytungstate Na9[{Na(H2O)2}3{Cu(H2O)}3(BiW9O33)2]?2H2O is obtained by the reaction of Na2WO4·2H2O, Bi(NO3)3·5H2O with CuCl2·2H2O at pH≈6. The structure and chemical composition are de-termin...The heteropolytungstate Na9[{Na(H2O)2}3{Cu(H2O)}3(BiW9O33)2]?2H2O is obtained by the reaction of Na2WO4·2H2O, Bi(NO3)3·5H2O with CuCl2·2H2O at pH≈6. The structure and chemical composition are de-termined by X-ray diffraction analysis and elemental analysis. The crystal data and main structure refinement are: a=1.410(3) nm, b=2.338(5) nm, c=3.173(6) nm, =98.06(4)? V=10.354(35) nm3, monoclinic crystal system, space group: C2/c, Z=4, R1=0.0471, wR2=0.0642 [I>2(I)], R1=0.1371, wR2=0.0868 (all data). [{Na(H2O)2}3{Cu(H2O)}3W9O33)2]9- has D3h symmetry. IR, UV-vis spectra, TG curve and magnetic property of the complex were also discussed. The compound exhibits an antiferromagnetic coupling with J=-8.08 cm-1 and g=2.21.展开更多
The heteropolytungstate(NH_4)_(20)[Na_2(H_2O)_2Ni(H_2O)_5{Ni(H_2O)}_2As_4W_(40)O_(140)] · 61H_2O is obtained by thereaction of Na_(27)[NaAs_4W_(40)O_(140)] · 60H_2O with NiCl_2 · 6H_2O and NH_4Cl in pH ...The heteropolytungstate(NH_4)_(20)[Na_2(H_2O)_2Ni(H_2O)_5{Ni(H_2O)}_2As_4W_(40)O_(140)] · 61H_2O is obtained by thereaction of Na_(27)[NaAs_4W_(40)O_(140)] · 60H_2O with NiCl_2 · 6H_2O and NH_4Cl in pH ≈ 4.0. Thestructure and chemical composition are determined by X-ray diffraction analysis and elementanalysis. The crystal data and main structure refinement are: a = 1.33135(18) nm, b = 1.9722(3) nm,c = 3.6430(5) nm, a = 78.010(2)°, β = 82.145(2)°, γ= 74.385(2)°, V= 8.978(2) nm^3, tricliniccrystal system, space group: P_1, Z= 2, R1 = 0.0512, and wR2 = 0.0684(I > 2σ). The four S2 sites ofthe big cyclic ligand [As_4W_(40)O_(140)]^(28-) are occupied by two Na^+ and two Ni^(2+)respectively, and each site supplies four O_d coordinating to metal ion. The coordination number ofNi^(2+) is six, and that of two Na^+ is five and six respectively. The third Ni^(2+) locates outsidethe cyclic [As_4W_(40)O_(140)]^(28-) and connects with one O_d, and its coordination number is six.展开更多
基金This work was supported by the National Natural Science Foundation of China
文摘The emission spectra of some heteropolytungstates containing europium, K.[Eu(XW11 O39)2](X = P, Ge, As, or Ga), K17[EuCAs2W17O61)2] and K16H9EuAs4W40O140 have been investigated and the structures of these compounds are discussed. The emission spectra at room temperature are very similar to each other in terms of both the number of bands and transition frequencies, showing that they have the similar structures to those of K16[Ce(P2W17O61)2] and K12[U(GeW11O39)2].
基金Supported by the National Natural Science Foundation of China(Nos.21871026,21671019,21701010).
文摘Three novel scandium-containing heteropolytungstates[Sc3(H2O)3NO(PW9O34)2]^10(1a)Scs(H2O)2(GeW6O34)2(GeW6O26)2]^12(2a)and[Sc11(W6O10)2(OH)2(H2O)16(BiW9O33)6]^27(3a)were synthesized by reactions of Sclllions with trilacunary Keggin precursors,[A-a-XW9O34]^n(X=P,Ge,n=9,10)or[B-a-BiW9O33]^9,in NaOAc/HOAc buffer solution under conventional synthetic condition,respectively.All the three compounds were characterized by means of single-crystal X-ray diffraction(XRD),Fourier transform-infrared(FTIR)spectroscopy ultraviolet-visible(UV-Vis)spectroscopy,elemental analysis,and thermogravimetric analysis.The aqueous solutior stability of the sandwich polvanion[Sc3(H2O)3(pw9O34)2]^10-was also verified by electrospray ionization mass Spectrometry(ESI-MS)due to its good solubility in water.
文摘A series of heteropolytungstates has been synthesized and utilized as catalysts to catalyze oxidation of benzyl alcohol with aqueous hydrogen peroxide. The results indicated that three of these catalysts showed the properties of reaction-controlled phasetransfer catalysis, and they had excellent catalytic ability to the oxidation of benzyl alcohol. No other by-products were detected by gas chromatography. Once the hydrogen peroxide was consumed completely, the catalyst precipitated from solvent, and the results of the catalyst recycle showed that the catalyst had high stability.
文摘The Eu3+-doped Na24P2W22O83 has been prepared by solid state reaction, and characterized by element analysis, infrared spectroscopy, powder X-ray diffractometry. The emission and excitation spectra were measured. The luminescence properties of Eu3+-doped Na24P2W22O83 and the energy transfer mechanism were discussed.
基金the foundation of NSF of Fujian Province (2000F002)the foundation of Education Committee of Fujian Province (JA00137).
文摘The complex Na10[LaSiW11O39(H2O)4]2?2H2O was synthesized and crystallized in monoclinic,space group P21/n with cell parameters: a=17.9786(9), b=23.5940(2), c=13.1289(8), β=90.141(2)°, V=5569.1(6)3, Mr=6336.60, Z=2, Dc=3.779g/cm3, (MoKa)= 0.71069? =23.533mm-1, F(000)=5488, T=293(2)K. The final refinement for 8404 observed reflections with I >2s (I) gave R = 0.0595 and wR = 0.1366. Both lanthanide cations are coordinated by nine oxygen atoms in a distorted squareantiprism environment. The LaO bond lengths are from 2.52(1) to 2.63(2).
基金This work was supported by the National Natural Science Foundation of China(20371011).
文摘A new heteropolytungstate, [H2bpy]3[SiMnW11O39]· 1.25H2O （1）, has been prepared under mild hydrothermal conditions and structurally characterized by single crystal X-ray diffraction. It is the first characterized compound containing ID zigzag chain of transition metal substituted Keggin heteropolytungstate, which is connected through a common oxygen atom. The elemental analysis and IR of it are also described.
基金This project is financially supported by the National Natural Science Foundation of China (No. 29971024) the Natural Science Foundation of Hubei Education Committee (No. 2002A00008)
文摘The Eu^(3+)-doped Na^(24)As_2W_(22)O_83 phosphor has been prepared by solidstare reaction from Na_3AsO_4.12H_2O, Na_2WO_4.2H_2O and WO_3, and characterized by elementalanalysis, infrared spectroscopy and powder X-ray diffractometry. According to the measurements withX-ray diffraction, this material belongs to orthorhombic system with its lattice constants: avelence 1.4750 nm, b velence 1.1944 nm, c velence 1.1062 nm, it is consistent with space groupD_2~4-P2_12_12_1 (No.19). The emission and excitation spectra were measured. The luminescentproperties of Eu^(3+)-doped Na^(24)As_2W_(22)O_83 and mechanism of energy transfer were discussed.
基金Supported by the foundation of laboratory of rare earth chemistry and physics
文摘The redox properties of K17[Ln(As2W17O61)2](Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Tm or Yb) in solution were investigated using polarographic and cyclic voltammographic methods. Experimental results indicate that the heteropolyanions underwent three-step-two-electron-tungsten-reduction processes, and each reduction process was accompanied by adding two protons.
基金Project supported by Visiting Scholar Foundation of Key Lab in Chinese Universities and the Education Commission of Shaanxi Province (No. 03JK077).
文摘The heteropolytungstate Na9[{Na(H2O)2}3{Cu(H2O)}3(BiW9O33)2]?2H2O is obtained by the reaction of Na2WO4·2H2O, Bi(NO3)3·5H2O with CuCl2·2H2O at pH≈6. The structure and chemical composition are de-termined by X-ray diffraction analysis and elemental analysis. The crystal data and main structure refinement are: a=1.410(3) nm, b=2.338(5) nm, c=3.173(6) nm, =98.06(4)? V=10.354(35) nm3, monoclinic crystal system, space group: C2/c, Z=4, R1=0.0471, wR2=0.0642 [I>2(I)], R1=0.1371, wR2=0.0868 (all data). [{Na(H2O)2}3{Cu(H2O)}3W9O33)2]9- has D3h symmetry. IR, UV-vis spectra, TG curve and magnetic property of the complex were also discussed. The compound exhibits an antiferromagnetic coupling with J=-8.08 cm-1 and g=2.21.
基金This work was supported by the Foundation of Shaanxi Key Laboratory of Chemical Reaction Engineering.
文摘The heteropolytungstate(NH_4)_(20)[Na_2(H_2O)_2Ni(H_2O)_5{Ni(H_2O)}_2As_4W_(40)O_(140)] · 61H_2O is obtained by thereaction of Na_(27)[NaAs_4W_(40)O_(140)] · 60H_2O with NiCl_2 · 6H_2O and NH_4Cl in pH ≈ 4.0. Thestructure and chemical composition are determined by X-ray diffraction analysis and elementanalysis. The crystal data and main structure refinement are: a = 1.33135(18) nm, b = 1.9722(3) nm,c = 3.6430(5) nm, a = 78.010(2)°, β = 82.145(2)°, γ= 74.385(2)°, V= 8.978(2) nm^3, tricliniccrystal system, space group: P_1, Z= 2, R1 = 0.0512, and wR2 = 0.0684(I > 2σ). The four S2 sites ofthe big cyclic ligand [As_4W_(40)O_(140)]^(28-) are occupied by two Na^+ and two Ni^(2+)respectively, and each site supplies four O_d coordinating to metal ion. The coordination number ofNi^(2+) is six, and that of two Na^+ is five and six respectively. The third Ni^(2+) locates outsidethe cyclic [As_4W_(40)O_(140)]^(28-) and connects with one O_d, and its coordination number is six.
