Rare earth(Ⅲ)diphenyl-4-amine sulfonates(RE(DAS)3·xH2O,RE=Eu^3+,Tb^3+)phosphors were synthesized by precursor method from barium diphenyl-4-amine sulfonate and rare earth sulfates.FTIR,TG/DSC coupled to mass spe...Rare earth(Ⅲ)diphenyl-4-amine sulfonates(RE(DAS)3·xH2O,RE=Eu^3+,Tb^3+)phosphors were synthesized by precursor method from barium diphenyl-4-amine sulfonate and rare earth sulfates.FTIR,TG/DSC coupled to mass spectrometry(TG/DSC/MS),X-ray powder diffraction(XPD),scanning electron microscopy(SEM)and photo luminesce nce(PL)spectroscopy were utilized to structurally and morphologically characterize the samples.Thermal decomposition of Eu(DAS)3·7H2O and Tb(DAS)3·2H2O at 973 K under dynamic air atmosphere results in crystalline Eu2O2SO4 and Tb2O2SO4 materials,respectively.Accordingly,MS spectra reveal the liberation of thermal decomposition products of precursors,largely as CO2,NO2 and SO2 gases.The diphenyl-4-amine sulfonate(DAS)ligand demonstrats a good stabilizing property for Eu^3+and Tb^3+ions.The Eu(DAS)3·7H2O and Tb(DAS)3·2H2O compounds display efficient red and green emissions,under UV excitation,arising from the 5D0→7FJ(J=0-4)and 5D4→7FJ(J=0-6)transitions of the Eu^3+and Tb^3+ions,respectively.展开更多
The complexation of Pb^（2＋）by diallyl disulfide（DADS）, dimethyl disulfide（DMDS） and diallyl sulfide（DAS）has been studied by differential pulse voltammetry. Stability constants,（log b）, of the 1：1（PbL） an...The complexation of Pb^（2＋）by diallyl disulfide（DADS）, dimethyl disulfide（DMDS） and diallyl sulfide（DAS）has been studied by differential pulse voltammetry. Stability constants,（log b）, of the 1：1（PbL） and 1：2（PbL_2） complexes, where L = ligand, were found to be in the range of ca. 3.8-4.2 and 9.4-10.2,respectively. Complex formation is accompanied with a significant decrease in the peak current and the shift of the Pb2＋/Pb half-wave potential to a higher one upon the addition of the sulfur containing ligands（L）. The formation of 1：1 and 1：2 complexes, i.e., PbL^（2＋）and PbL_2^（2＋）was observed in the case of the three ligands. The consecutive formation constants of labile lead complexes with DADS, DMDS, and DAS were determined at 298 K by the method of De Ford and Hume. Apparently due to the large size of the lead ion,steric hindrance caused by the greater steric bulk of DADS compared to that of DMDS have little or no effects on the formation constants, so that very similar values were obtained in the case of the two ligands. Also, the possible participation of C=C double bonds in coordination with the metal center in the case of DADS appears to compensate for the steric effects caused by the larger size of this ligand. In agreement with the Jorgensen principle of symbiosis, the second formation constants were found to be approximately six orders of magnitude greater than the first ones.展开更多
基金Project supported by Higher Education Personnel Improvement Coordination(CAPES),Laboratory of Thermal Analysis Prof.Ivo Giolito(LATIG-USP),Laboratory of f-block Elements(Leb-f)USP,Petroleum Nucleus(LABPETRO-UFES)of Federal University of Espirito Santo,Institute of Low Temperature and Structure Research and the Polish Academy of Sciences
文摘Rare earth(Ⅲ)diphenyl-4-amine sulfonates(RE(DAS)3·xH2O,RE=Eu^3+,Tb^3+)phosphors were synthesized by precursor method from barium diphenyl-4-amine sulfonate and rare earth sulfates.FTIR,TG/DSC coupled to mass spectrometry(TG/DSC/MS),X-ray powder diffraction(XPD),scanning electron microscopy(SEM)and photo luminesce nce(PL)spectroscopy were utilized to structurally and morphologically characterize the samples.Thermal decomposition of Eu(DAS)3·7H2O and Tb(DAS)3·2H2O at 973 K under dynamic air atmosphere results in crystalline Eu2O2SO4 and Tb2O2SO4 materials,respectively.Accordingly,MS spectra reveal the liberation of thermal decomposition products of precursors,largely as CO2,NO2 and SO2 gases.The diphenyl-4-amine sulfonate(DAS)ligand demonstrats a good stabilizing property for Eu^3+and Tb^3+ions.The Eu(DAS)3·7H2O and Tb(DAS)3·2H2O compounds display efficient red and green emissions,under UV excitation,arising from the 5D0→7FJ(J=0-4)and 5D4→7FJ(J=0-6)transitions of the Eu^3+and Tb^3+ions,respectively.
基金Practical support of this work by University of Zanjan and Institute for Advanced Studies in Basic Sciences (IASBS) research councils is acknowledgedsupported in part by the Iranian National Science Foundation (INSF) under grant No.90001029
文摘The complexation of Pb^（2＋）by diallyl disulfide（DADS）, dimethyl disulfide（DMDS） and diallyl sulfide（DAS）has been studied by differential pulse voltammetry. Stability constants,（log b）, of the 1：1（PbL） and 1：2（PbL_2） complexes, where L = ligand, were found to be in the range of ca. 3.8-4.2 and 9.4-10.2,respectively. Complex formation is accompanied with a significant decrease in the peak current and the shift of the Pb2＋/Pb half-wave potential to a higher one upon the addition of the sulfur containing ligands（L）. The formation of 1：1 and 1：2 complexes, i.e., PbL^（2＋）and PbL_2^（2＋）was observed in the case of the three ligands. The consecutive formation constants of labile lead complexes with DADS, DMDS, and DAS were determined at 298 K by the method of De Ford and Hume. Apparently due to the large size of the lead ion,steric hindrance caused by the greater steric bulk of DADS compared to that of DMDS have little or no effects on the formation constants, so that very similar values were obtained in the case of the two ligands. Also, the possible participation of C=C double bonds in coordination with the metal center in the case of DADS appears to compensate for the steric effects caused by the larger size of this ligand. In agreement with the Jorgensen principle of symbiosis, the second formation constants were found to be approximately six orders of magnitude greater than the first ones.
