A series of seven novel lanthanide（Ⅲ ） nitrato complexes with 4-[ N-（2-methoxybenzylimine）formyl] 1-2, 3- dimethyl-1-phenyl-3-pyazolin-5-one （2mbfa）, were synthesized. These complexes were characterized by elem...A series of seven novel lanthanide（Ⅲ ） nitrato complexes with 4-[ N-（2-methoxybenzylimine）formyl] 1-2, 3- dimethyl-1-phenyl-3-pyazolin-5-one （2mbfa）, were synthesized. These complexes were characterized by elemental analysis, molecular mass determination, conductance and magnetic moment measurements, IR, UV-visible, and ^13CNMR spectral studies, In these complexes, the Schiff base, 2mbfa, acts as neutral bidentate ligand by utilizing the carbonyl oxygen and azomethine nitrogen as donor sites. All the three nitrate ions are also coordinated unidentately with 7 coordination for the lanthanide（Ⅲ） ions with a tentative monocapped octahedral geometry for the complexes. All the seven lanthanide（Ⅲ） complexes have a general formula, [ Ln（2mbfa）：（NO3）3 ].展开更多
Two new mononuclear lanthanide（Ⅲ） complexes Ln（pytz）3（H2O）3·（H2O）3.5[Ln=Tb（1）;Eu（2）;Hpytz=5-（2-pyridyl）tetrazole] were synthesized by reacting Hpytz with the corresponding lanthanide（Ⅲ） ions and...Two new mononuclear lanthanide（Ⅲ） complexes Ln（pytz）3（H2O）3·（H2O）3.5[Ln=Tb（1）;Eu（2）;Hpytz=5-（2-pyridyl）tetrazole] were synthesized by reacting Hpytz with the corresponding lanthanide（Ⅲ） ions and characterized.The single crystal X-ray diffraction analysis reveals that complexes 1 and 2 are isostructural and the lanthanide（Ⅲ） ions in both complexes 1 and 2 are nine-coordinated,with three oxygen atoms of three coordination water molecules and six nitrogen atoms of three pytz ligands,forming a monocapped square antiprism.Extensive hydrogen bonds exist,resulting in a three-dimensional supramolecular network structure by hydrogen-bonds in both complexes 1 and 2,respectively.Complex 1 exhibits typical green fluorescence of Tb（Ⅲ） ion and complex 2 red fluorescence of Eu（Ⅲ） ion,in solid state at room temperature.展开更多
Ultrathin TiO2 nanosheets with coexposed {001}/{101} facets have attracted considerable attention because of their high photocatalytic activity. However, the charge-separated states in the TiO2 nanosheets must be exte...Ultrathin TiO2 nanosheets with coexposed {001}/{101} facets have attracted considerable attention because of their high photocatalytic activity. However, the charge-separated states in the TiO2 nanosheets must be extended to further enhance their photocatalytic activity for H2 evolution. Herein, we present a successful attempt to selectively dope lanthanide ions into the {101} facets of ultrathin TiO2 nanosheets with coexposed {001}/{101} facets through a facile one-step solvothermal method. The lanthanide doping slightly extended the light-harvesting region and markedly improved the charge-separated states of the TiO2 nanosheets as evidenced by UV-vis absorption and steady-state/transient photoluminescence spectra. Upon simulated sunlight irradiation, we observed a 4.2-fold enhancement in the photocatalytic H2 evolution activity of optimal Yb3+-doped TiO2 nanosheets compared to that of their undoped counterparts. Furthermore, when Pt nanoparticles were used as cocatalysts to reduce the H2 overpotential in this system, the photocatalytic activity enhancement factor increased to 8.5. By combining these results with those of control experiments, we confirmed that the extended charge-separated states play the main role in the enhancement of the photocatalytic H2 evolution activity of lanthanide-doped TiO2 nanosheets with coexposed {001}/{101} facets.展开更多
Extractability and extraction mechanism of lanthanide ions were investigated by using a new extractant,N,Nn,N′,N′-tetrabutyl-3-oxa-diglycolamide(TBDGA),in toluene from nitric acid media.The effects of HNO_3 and TBDG...Extractability and extraction mechanism of lanthanide ions were investigated by using a new extractant,N,Nn,N′,N′-tetrabutyl-3-oxa-diglycolamide(TBDGA),in toluene from nitric acid media.The effects of HNO_3 and TBDGA concentrations,and temperature,on extraction of lanthanide ions were studied.Stoichiometrics of the main extracted species were HNO_3·TBDGA and M(NO_3)_3-3TBDGA(M = Er,Dy,Tb,Gd,La,Ce,Nd,Sm and Eu).The extracted species for metal ions were established to be ionic complex.In this complex,nitrate anion was not coordinated to the central ion.The extraction pattern increased gradually across the lanthanide ions series,showing enhanced affinity of TBDGA toward heavy lanthanide ions.Thermodynamic parameters were investigated for the exothermic extraction reaction.展开更多
A mixture containing eleven lanthanide ions was separated and detected on an anion exchange co lumn by ion chromatography with indirect photometry detection (IPC).An aqueous solution of 1.5×10 -2 mol/L ni...A mixture containing eleven lanthanide ions was separated and detected on an anion exchange co lumn by ion chromatography with indirect photometry detection (IPC).An aqueous solution of 1.5×10 -2 mol/L nitrilotri(methylenephosphonic) acid and 2.5×10 -3 mol/L tiron was used as the eluent in which the former served as complexing agent and eluent,the latter played as color reagent and eluent.The effects of acidity,concentration and composition of eluent on the retention behavior of the analytes and detection sensitivity are discussed.展开更多
Four kinds of lanthanide ions（Sm^3＋,Yb^3＋,Eu^3＋,La^3＋）as an additive were added into the aqueous solution containing methanol,respectively,and their effects on methanol elecotrooxidation in aqueous solutions wer...Four kinds of lanthanide ions（Sm^3＋,Yb^3＋,Eu^3＋,La^3＋）as an additive were added into the aqueous solution containing methanol,respectively,and their effects on methanol elecotrooxidation in aqueous solutions were studied with cyclic voltammetry.The results show that the four kinds of ions have promotion action upon the electrooxidation of methanol to different degrees.The best additive,Sm^3＋,can increase the anodic oxidation current of methanol by 80%and the peak potential shifted negatively about 50 mV.The promotion effects of the lanthanide ions were considered to be related to the extranuclear electron distribution of these ions and their adsorption on the Pt electrode surface.展开更多
Seven new lanthanide（Ⅲ） complexes with 4-hydroxyantipyrine were synthesized. These complexes were characterized by elemental analysis, molar conductance, magnetic moment measurements, FT-IR, electronic and 1HNMR sp...Seven new lanthanide（Ⅲ） complexes with 4-hydroxyantipyrine were synthesized. These complexes were characterized by elemental analysis, molar conductance, magnetic moment measurements, FT-IR, electronic and 1HNMR spectra, X-ray powder diffraction, and thermogravimetric studies. The ligand, 4-hydroxyantipyrine （hap）, contained carbonyl oxygen and hydroxyl oxygen as potential donor sites. On coordination, deprotonation occurred and as a result, hap acted as a monobasic bidentate ligand. A coordination number 6 was assigned to the lanthanide（Ⅲ） ions in these complexes with orthorhombic structure. All the complexes were thermally stable-150℃ and underwent decomposition in three stages with the formation of Ln2O3 as the final residues.展开更多
Two new coordination polymers,[Ln（oba）（ox）0.5（H2O）2]n（Ln = Ho（1）,Eu（2）;H2oba = 4,4？-oxybis（benzoic acid）,H2ox = oxalic acid） have been synthesized under hydrothermal conditions.According to single-cryst...Two new coordination polymers,[Ln（oba）（ox）0.5（H2O）2]n（Ln = Ho（1）,Eu（2）;H2oba = 4,4？-oxybis（benzoic acid）,H2ox = oxalic acid） have been synthesized under hydrothermal conditions.According to single-crystal X-ray diffraction analyses,complex 1 crystallizes in the monoclinic system,space group P21/c with a = 13.783（2）,b =10.0120（15）,c = 12.1974（18） ,β = 105.217（2）°,V = 1624.2（4） 3,C15H12O9Ho,Mr = 501.18,Z = 4,Dc = 2.050 g/cm3,F（000） = 964,μ = 4.919 mm-1,λ（MoKα） = 0.71073 ？,GOOF = 1.124,the final R = 0.0239 and wR = 0.0570 for 3310 independent reflections with Rint = 0.0298.Complexes 2 and 1 are isostructural.Oba and ox ligands bridge the Ln（III） ions into 2D layers with（4,4） topology,which are further interlinked into a 3D supramolecular network by hydrogen bonds.TG curves of the two complexes are studied to examine their thermal stabilities.Additionally,complex 2 shows red fluorescence in the solid state at room temperature.展开更多
The structure of phenylalanine transfer ribonucleic acid(tRNA Phe ) in solution was explored by 1 H NMR spectroscopy to evaluate the effect of lanthanide ion on the structural and conformational change. It w...The structure of phenylalanine transfer ribonucleic acid(tRNA Phe ) in solution was explored by 1 H NMR spectroscopy to evaluate the effect of lanthanide ion on the structural and conformational change. It was found that La 3+ ions possess specific effects on the imino proton region of the 1 H NMR spectra for yeast tRNA Phe . The dependence of the imino proton spectra of yeast tRNA Phe as a function of La 3+ concentration was examined, and the results suggest that the tertiary base pair G 15 ·C 48 , which is located in the terminal in the augmented dihydrouridine helix(D helix), was markedly affected by La 3+ (shifted to downfield by as much as 0 35). Base pair U 8·A 14 in yeast tRNA Phe , which are stacked on G 15 ·C 48 , was also affected by added La 3+ when 1～2 Mg 2+ were also present. Another imino proton that may be affected by La 3+ in yeast tRNA Phe is that of the tertiary base pair G 19 ·C 56 . The assignment of this resonance in yeast tRNA Phe is tentative since it is located in the region of highly overlapping resonances beween 12 6 and 12 2. This base pair helps to anchor the D loop to the TΨC loop. The binding of La 3+ caused conformational change of tRNA, which is responsible for shifts to upfield or downfield in 1 H NMR spectra.展开更多
Two isomorphous 2D zigzag-ladder structure coordination polymers containing coordination supramolecular capsules are reported,which are built by trivalent lanthanide ions,pyridine N-oxide（PNO） and p-sulfonatothiacal...Two isomorphous 2D zigzag-ladder structure coordination polymers containing coordination supramolecular capsules are reported,which are built by trivalent lanthanide ions,pyridine N-oxide（PNO） and p-sulfonatothiacalix[4]arene（H4TCAS4-）：[Ln2（PNO）2（H2O）10？（H2TCAS）2].[Ln2（H2TCAS）2（H2O）6（MeOH）2].2MeOH.12H2O（Ln = La,1;Nd,2）.Crystal data for complex 1：C31H51La2NO33S8,Mr = 1500.03,triclinic system,P 1 space group,with a = 11.732（2）,b = 15.007（3）,c = 15.262（3）,α = 78.05（3）,β = 80.77（3）,γ = 83.89（3）°,Z = 2,V = 2587.3（9）3,Dc = 1.925 g/cm3,μ = 2.051 mm-1,F（000） = 1500,the final R = 0.0300 and wR = 0.0823;and those for complex 2：C31H51Nd2NO33S8,Mr = 1510.69,triclinic system,P1 space group,with a = 11.719（2）,b = 14.941（3）,c = 15.157（3）,α = 78.03（3）,β = 80.84（3）,γ = 83.95（3）°,Z = 2,V = 2555.9（9）3,Dc = 1.963 g/cm3,μ = 2.436 mm-1,F（000） = 1512,the final R = 0.0493 and wR = 0.1267.There are two coordination environments of lanthanide ions.One is bridged by two PNO molecules forming a dimeric Ln ion in the O,O’-μ2 mode.The dinuclear ions are shrouded by two H2TCAS6-ions through coordination interactions and hydrogen bonds.The other coordination mode of Ln ions is a zigzag 1D chain linked by up-down H2TCAS6-ions.By the coordination capsules,the complexes form 2D zigzag-ladder structure coordination polymers.展开更多
The molecular interactions between Nd^(3+), Gd^(3+)and Yb^(3+) and DPPC in multibilayer have been studied by Fourier transform infrared spectroscopy. The results show that incorporations of the lanthanide ions conside...The molecular interactions between Nd^(3+), Gd^(3+)and Yb^(3+) and DPPC in multibilayer have been studied by Fourier transform infrared spectroscopy. The results show that incorporations of the lanthanide ions considerably shift the gel to liquid-crystal phase transition to higher temperatures. The incorporations of Gd^(3+) and Yb^(3+) obviously reduce the cooperations of the transition. The phosphate region of the spectra indicates that the Ln^(3+) binding to DPPC forms DPPC-Ln^(3+)complex and the Lna^(3+)binding is not dependent on the phase state of DPPC. The C-H stretching region of the spectra suggests that the incorporation of Ln^(3+)increases the conformational order of DPPC both in gel and in liquid-crystal phase as a result of the reduction of gauche rotamers.展开更多
Organic?inorganic hybrid coating on the surface of aluminum-tube used in refrigeration equipment using cerium ion (III) as the additive was fabricated by sol?gel method, and the structure of the coating was confirmed ...Organic?inorganic hybrid coating on the surface of aluminum-tube used in refrigeration equipment using cerium ion (III) as the additive was fabricated by sol?gel method, and the structure of the coating was confirmed by FT-IR. The results of the characterization show that the corrosion resistance of the coating with 1.5 mmol/L cerium ion (III) gains significant improvement, in which the colour retention time of CuSO4 extends to 500 s, the anti-acid and alkali corrosion rates reduce by 67% and 70% compared with the blank one, respectively, and the salt spray tests also show good corrosion resistance. The electrochemical tests demonstrate that the self-corrosion current density and potential of the sample with hybrid coating are about 2.877×10?7 A/cm2 and?0.550 V, respectively. The metallographic and SEM images show that the hybrid coating is uniform and dense, and the EDS analysis confirms that the coating is mainly composed of Al, Si and Ce elements.展开更多
The adsorption behavior and mechanism of Bi（Ⅲ） ions on the rutile-water interface were investigated through micro-flotation, Zeta potential measurement, adsorption amount measurement and X-ray photoelectron spectro...The adsorption behavior and mechanism of Bi（Ⅲ） ions on the rutile-water interface were investigated through micro-flotation, Zeta potential measurement, adsorption amount measurement and X-ray photoelectron spectroscopy（XPS）. According to the results of micro-flotation, Bi（Ⅲ） ions could largely improve the rutile flotation recovery（from 62% to 91%）, and they could increase the activating sites and reduce the competitive adsorption between nonyl hydroxamic acid negative ions and OH-ions, which determined that Bi（Ⅲ） ions were capable of activating rutile flotation. The adsorption of Bi（Ⅲ） ions onto the rutile surface led to the shift of Zeta potential into the positive direction, which was good for the adsorption of nonyl hydroxamic acid anions. In addition, the results of XPS indicated that the chemical environment around Ti atom had not changed before and after the adsorption of Bi（Ⅲ） ions. Based on the adsorption mechanism of Bi（Ⅲ） ions, it was deduced that firstly Bi（Ⅲ） ions occupied the vacancies of the original Ca^2＋, Mg^2＋ and Fe^2＋ ions on the rutile surface; secondly Bi（Ⅲ） ions covered on the rutile surface in the form of hydroxides.展开更多
Luminescence quench is common in overdoped upconversion nanoparticles.Various methods have been proposed to counteract the adverse effects of concentration quenching on luminescence,but in upconversion nanoparticles t...Luminescence quench is common in overdoped upconversion nanoparticles.Various methods have been proposed to counteract the adverse effects of concentration quenching on luminescence,but in upconversion nanoparticles that are highly doped with both sensitizers and activators,the factors that contribute to the diminishing of the emission cannot be summarized by a single cause.Herein,a core-shell design is used to spatially separate the sensitizer(Yb^(3+))and activator(Er^(3+))and to modulate the emission by changes in the distribution position as well as the concentration of the dopant ions in order to probe the factors affecting the luminescence.When the sensitizer ions are located in the core,the luminescence intensity of the nanoparticles is significantly weaker than that of the other distribution,which implies that the effect of sensitizer and activator on luminescence in the highly doped state has a different and more complex mechanism.The intensity of the emission is more affected by Yb^(3+)than Er^(3+),which includes not only the self-quenching of Yb^(3+),but also the dominance in the Yb^(3+)-Er^(3+)cross-relaxation.In this finding may provide new ideas for revealing the reasons for the diminished luminescence of highly doped upconversion nanoparticles and thus for enhancing luminescence.展开更多
The toxicity of lead ions has become the severe challenge for the all-inorganic lead halide p erovskite materials,although some works have rep orted the lead-free perovskite nanocrystals(NCs),the photoluminescence qua...The toxicity of lead ions has become the severe challenge for the all-inorganic lead halide p erovskite materials,although some works have rep orted the lead-free perovskite nanocrystals(NCs),the photoluminescence quantum yield(PLQY)of these materials is still unsatisfactory.Meanwhile,because the halogen ions can be easily exchanged,the controllable multicolor emission in perovskite NCs is difficult to realize in current reports.In this work,we introduced lanthanide ions into lead-free Cs_(3)Sb_(2)Cl_(9) perovskite NCs.Benefitting from the energy transfer between Cs_(3)Sb_(2)Cl_(9) perovskite NC host and lanthanide ions,the multicolor emission was realized.Based on controlling the doping concentration of Tb^(3+)and Eu^(3+)ions,the white light emission under UV excitation would be turned easily in the Tb^(3+)/Eu^(3+)codoped NCs.In addition,efficient energy transfer from perovskite NCs to Tb^(3+)or Eu^(3+)ions is beneficial to improving the optical properties of lead-free perovskite NCs,resulting in maximum PLQYs of red,green and white light emission of 22.6%,19.7%and 28.5%,respectively.Finally,a white light emitting device(WLED)was fabricated with a power efficiency of 18.5 lm/W,which presents the Commission Internationale de l'Eclairage(CIE)of(0.33,0.35).展开更多
Humic substances are ubiquitous redox-active organic compounds of environment. In this study, experiments were conducted to determine the reduction capacity of humic acid in the man-ix of bromate and Fe（Ⅲ） solution...Humic substances are ubiquitous redox-active organic compounds of environment. In this study, experiments were conducted to determine the reduction capacity of humic acid in the man-ix of bromate and Fe（Ⅲ） solutions and the role of Fe（Ⅲ） in this redox process. The results showed that the humic acid regenerated Fe（Ⅱ） and reduced bromate abiotically. The addition of Fe（Ⅲ） could accelerate the bromate reduction rate by forming humic acid-Fe（Ⅲ） complexes. Iron species acts as electron mediator and catalyst for the bromate reduction by humic acid, in which humic acid transfers electrons to the complexed Fe（Ⅲ） to form Fe（Ⅱ）, and the regenerated Fe（Ⅱ） donate the electrons to bromate. The kinetics study on bromate reduction further indicated that bromate reduction by humic acid-Fe（Ⅲ） complexes is pH dependent. The rate decreased by 2-fold with the increase in solution pH by one unit. The reduction capacity of Aldrich humic acid was observed to be lower than that of humic acid or natural organic matter of Suwanne River, indicating that such redox process is expected to occur in the environment.展开更多
基金Ph.D. Programme at the Department of Chemistry, University of Kerala, India
文摘A series of seven novel lanthanide（Ⅲ ） nitrato complexes with 4-[ N-（2-methoxybenzylimine）formyl] 1-2, 3- dimethyl-1-phenyl-3-pyazolin-5-one （2mbfa）, were synthesized. These complexes were characterized by elemental analysis, molecular mass determination, conductance and magnetic moment measurements, IR, UV-visible, and ^13CNMR spectral studies, In these complexes, the Schiff base, 2mbfa, acts as neutral bidentate ligand by utilizing the carbonyl oxygen and azomethine nitrogen as donor sites. All the three nitrate ions are also coordinated unidentately with 7 coordination for the lanthanide（Ⅲ） ions with a tentative monocapped octahedral geometry for the complexes. All the seven lanthanide（Ⅲ） complexes have a general formula, [ Ln（2mbfa）：（NO3）3 ].
基金Supported by the National Natural Science Foundation of China(No.20975009)
文摘Two new mononuclear lanthanide（Ⅲ） complexes Ln（pytz）3（H2O）3·（H2O）3.5[Ln=Tb（1）;Eu（2）;Hpytz=5-（2-pyridyl）tetrazole] were synthesized by reacting Hpytz with the corresponding lanthanide（Ⅲ） ions and characterized.The single crystal X-ray diffraction analysis reveals that complexes 1 and 2 are isostructural and the lanthanide（Ⅲ） ions in both complexes 1 and 2 are nine-coordinated,with three oxygen atoms of three coordination water molecules and six nitrogen atoms of three pytz ligands,forming a monocapped square antiprism.Extensive hydrogen bonds exist,resulting in a three-dimensional supramolecular network structure by hydrogen-bonds in both complexes 1 and 2,respectively.Complex 1 exhibits typical green fluorescence of Tb（Ⅲ） ion and complex 2 red fluorescence of Eu（Ⅲ） ion,in solid state at room temperature.
基金supported by the National Natural Science Foundation of China(51772041,11474046,61775024)the Natural Science Foundation of Liaoning Province(20170540190,201602191)+3 种基金the Program for Liaoning Excellent Talents in University(LNET)(LR2015016,LR2017004)the Program for Dalian Excellent Talents(2016RQ069)the Science and the Technique Foundation of Dalian(2014J11JH134,2015J12JH201)the Fundamental Research Funds for the Central Universities(wd01206)~~
文摘Ultrathin TiO2 nanosheets with coexposed {001}/{101} facets have attracted considerable attention because of their high photocatalytic activity. However, the charge-separated states in the TiO2 nanosheets must be extended to further enhance their photocatalytic activity for H2 evolution. Herein, we present a successful attempt to selectively dope lanthanide ions into the {101} facets of ultrathin TiO2 nanosheets with coexposed {001}/{101} facets through a facile one-step solvothermal method. The lanthanide doping slightly extended the light-harvesting region and markedly improved the charge-separated states of the TiO2 nanosheets as evidenced by UV-vis absorption and steady-state/transient photoluminescence spectra. Upon simulated sunlight irradiation, we observed a 4.2-fold enhancement in the photocatalytic H2 evolution activity of optimal Yb3+-doped TiO2 nanosheets compared to that of their undoped counterparts. Furthermore, when Pt nanoparticles were used as cocatalysts to reduce the H2 overpotential in this system, the photocatalytic activity enhancement factor increased to 8.5. By combining these results with those of control experiments, we confirmed that the extended charge-separated states play the main role in the enhancement of the photocatalytic H2 evolution activity of lanthanide-doped TiO2 nanosheets with coexposed {001}/{101} facets.
基金Supported by the National Natural Science Foundation of China(No.21576112)Natural Science Foundation Project of Jilin Province(No.20130521019JH and 20150623024TC-19)+1 种基金Natural Science Foundation Project of the Education Department of Jilin Province(No.[2014]152)the Science and Technology Development Plan of Siping City(2015049)
文摘Three lanthanide（III） complexes [Ln（4-NCP）（1,4-BDC）]n·xn H2O（Ln = Pr（1）, Sm（2）, Nd（3）. 4-HNCP = 2-（4-carboxyphenyl）imidazo（4,5-f）（1,10）phenanthroline, 1,4-H2 BDC = benzene-1,4-dicarboxylic acid） have been hydrothermally synthesized and characterized via elemental analysis, infrared spectrometry and single-crystal X-ray diffraction. Structural analyses revealed that complexes 1~3 possess similar porous three-dimensional frameworks with the point symbol {4^（12）·6~3}. Meanwhile, complexes 1~3 exhibit excellent thermal stabilities and complex 2 exhibits characteristic luminescent property.
基金supported by the National Natural Science Foundation of China(21077044)Natural Science Foundation of Shandong Province(ZR2015BM030)
文摘Extractability and extraction mechanism of lanthanide ions were investigated by using a new extractant,N,Nn,N′,N′-tetrabutyl-3-oxa-diglycolamide(TBDGA),in toluene from nitric acid media.The effects of HNO_3 and TBDGA concentrations,and temperature,on extraction of lanthanide ions were studied.Stoichiometrics of the main extracted species were HNO_3·TBDGA and M(NO_3)_3-3TBDGA(M = Er,Dy,Tb,Gd,La,Ce,Nd,Sm and Eu).The extracted species for metal ions were established to be ionic complex.In this complex,nitrate anion was not coordinated to the central ion.The extraction pattern increased gradually across the lanthanide ions series,showing enhanced affinity of TBDGA toward heavy lanthanide ions.Thermodynamic parameters were investigated for the exothermic extraction reaction.
文摘A mixture containing eleven lanthanide ions was separated and detected on an anion exchange co lumn by ion chromatography with indirect photometry detection (IPC).An aqueous solution of 1.5×10 -2 mol/L nitrilotri(methylenephosphonic) acid and 2.5×10 -3 mol/L tiron was used as the eluent in which the former served as complexing agent and eluent,the latter played as color reagent and eluent.The effects of acidity,concentration and composition of eluent on the retention behavior of the analytes and detection sensitivity are discussed.
基金the National High-tech Research and Development Program of China(No.2002AA233051)the NationalNatural Science Foundation of China(No.20373019).
文摘Four kinds of lanthanide ions（Sm^3＋,Yb^3＋,Eu^3＋,La^3＋）as an additive were added into the aqueous solution containing methanol,respectively,and their effects on methanol elecotrooxidation in aqueous solutions were studied with cyclic voltammetry.The results show that the four kinds of ions have promotion action upon the electrooxidation of methanol to different degrees.The best additive,Sm^3＋,can increase the anodic oxidation current of methanol by 80%and the peak potential shifted negatively about 50 mV.The promotion effects of the lanthanide ions were considered to be related to the extranuclear electron distribution of these ions and their adsorption on the Pt electrode surface.
基金Project supported by Ph.D. programme at the Department of Chemistry, University of Kerala, Kariavattom Campus, Trivandrum-695 581 Kerala, India
文摘Seven new lanthanide（Ⅲ） complexes with 4-hydroxyantipyrine were synthesized. These complexes were characterized by elemental analysis, molar conductance, magnetic moment measurements, FT-IR, electronic and 1HNMR spectra, X-ray powder diffraction, and thermogravimetric studies. The ligand, 4-hydroxyantipyrine （hap）, contained carbonyl oxygen and hydroxyl oxygen as potential donor sites. On coordination, deprotonation occurred and as a result, hap acted as a monobasic bidentate ligand. A coordination number 6 was assigned to the lanthanide（Ⅲ） ions in these complexes with orthorhombic structure. All the complexes were thermally stable-150℃ and underwent decomposition in three stages with the formation of Ln2O3 as the final residues.
基金Supported by the National Natural Science Foundation of China (20971015,20876157)Fundamental Research Funds for the Central Universities (FRF-BR-10-002A)
文摘Two new coordination polymers,[Ln（oba）（ox）0.5（H2O）2]n（Ln = Ho（1）,Eu（2）;H2oba = 4,4？-oxybis（benzoic acid）,H2ox = oxalic acid） have been synthesized under hydrothermal conditions.According to single-crystal X-ray diffraction analyses,complex 1 crystallizes in the monoclinic system,space group P21/c with a = 13.783（2）,b =10.0120（15）,c = 12.1974（18） ,β = 105.217（2）°,V = 1624.2（4） 3,C15H12O9Ho,Mr = 501.18,Z = 4,Dc = 2.050 g/cm3,F（000） = 964,μ = 4.919 mm-1,λ（MoKα） = 0.71073 ？,GOOF = 1.124,the final R = 0.0239 and wR = 0.0570 for 3310 independent reflections with Rint = 0.0298.Complexes 2 and 1 are isostructural.Oba and ox ligands bridge the Ln（III） ions into 2D layers with（4,4） topology,which are further interlinked into a 3D supramolecular network by hydrogen bonds.TG curves of the two complexes are studied to examine their thermal stabilities.Additionally,complex 2 shows red fluorescence in the solid state at room temperature.
文摘The structure of phenylalanine transfer ribonucleic acid(tRNA Phe ) in solution was explored by 1 H NMR spectroscopy to evaluate the effect of lanthanide ion on the structural and conformational change. It was found that La 3+ ions possess specific effects on the imino proton region of the 1 H NMR spectra for yeast tRNA Phe . The dependence of the imino proton spectra of yeast tRNA Phe as a function of La 3+ concentration was examined, and the results suggest that the tertiary base pair G 15 ·C 48 , which is located in the terminal in the augmented dihydrouridine helix(D helix), was markedly affected by La 3+ (shifted to downfield by as much as 0 35). Base pair U 8·A 14 in yeast tRNA Phe , which are stacked on G 15 ·C 48 , was also affected by added La 3+ when 1～2 Mg 2+ were also present. Another imino proton that may be affected by La 3+ in yeast tRNA Phe is that of the tertiary base pair G 19 ·C 56 . The assignment of this resonance in yeast tRNA Phe is tentative since it is located in the region of highly overlapping resonances beween 12 6 and 12 2. This base pair helps to anchor the D loop to the TΨC loop. The binding of La 3+ caused conformational change of tRNA, which is responsible for shifts to upfield or downfield in 1 H NMR spectra.
文摘Two isomorphous 2D zigzag-ladder structure coordination polymers containing coordination supramolecular capsules are reported,which are built by trivalent lanthanide ions,pyridine N-oxide（PNO） and p-sulfonatothiacalix[4]arene（H4TCAS4-）：[Ln2（PNO）2（H2O）10？（H2TCAS）2].[Ln2（H2TCAS）2（H2O）6（MeOH）2].2MeOH.12H2O（Ln = La,1;Nd,2）.Crystal data for complex 1：C31H51La2NO33S8,Mr = 1500.03,triclinic system,P 1 space group,with a = 11.732（2）,b = 15.007（3）,c = 15.262（3）,α = 78.05（3）,β = 80.77（3）,γ = 83.89（3）°,Z = 2,V = 2587.3（9）3,Dc = 1.925 g/cm3,μ = 2.051 mm-1,F（000） = 1500,the final R = 0.0300 and wR = 0.0823;and those for complex 2：C31H51Nd2NO33S8,Mr = 1510.69,triclinic system,P1 space group,with a = 11.719（2）,b = 14.941（3）,c = 15.157（3）,α = 78.03（3）,β = 80.84（3）,γ = 83.95（3）°,Z = 2,V = 2555.9（9）3,Dc = 1.963 g/cm3,μ = 2.436 mm-1,F（000） = 1512,the final R = 0.0493 and wR = 0.1267.There are two coordination environments of lanthanide ions.One is bridged by two PNO molecules forming a dimeric Ln ion in the O,O’-μ2 mode.The dinuclear ions are shrouded by two H2TCAS6-ions through coordination interactions and hydrogen bonds.The other coordination mode of Ln ions is a zigzag 1D chain linked by up-down H2TCAS6-ions.By the coordination capsules,the complexes form 2D zigzag-ladder structure coordination polymers.
文摘The molecular interactions between Nd^(3+), Gd^(3+)and Yb^(3+) and DPPC in multibilayer have been studied by Fourier transform infrared spectroscopy. The results show that incorporations of the lanthanide ions considerably shift the gel to liquid-crystal phase transition to higher temperatures. The incorporations of Gd^(3+) and Yb^(3+) obviously reduce the cooperations of the transition. The phosphate region of the spectra indicates that the Ln^(3+) binding to DPPC forms DPPC-Ln^(3+)complex and the Lna^(3+)binding is not dependent on the phase state of DPPC. The C-H stretching region of the spectra suggests that the incorporation of Ln^(3+)increases the conformational order of DPPC both in gel and in liquid-crystal phase as a result of the reduction of gauche rotamers.
基金Project(51404038)supported by the National Natural Science Foundation of China
文摘Organic?inorganic hybrid coating on the surface of aluminum-tube used in refrigeration equipment using cerium ion (III) as the additive was fabricated by sol?gel method, and the structure of the coating was confirmed by FT-IR. The results of the characterization show that the corrosion resistance of the coating with 1.5 mmol/L cerium ion (III) gains significant improvement, in which the colour retention time of CuSO4 extends to 500 s, the anti-acid and alkali corrosion rates reduce by 67% and 70% compared with the blank one, respectively, and the salt spray tests also show good corrosion resistance. The electrochemical tests demonstrate that the self-corrosion current density and potential of the sample with hybrid coating are about 2.877×10?7 A/cm2 and?0.550 V, respectively. The metallographic and SEM images show that the hybrid coating is uniform and dense, and the EDS analysis confirms that the coating is mainly composed of Al, Si and Ce elements.
基金Project(51474254)supported by the National Natural Science Foundation of ChinaProject(2013M531813)supported by the China Postdoctoral Science Foundation+1 种基金Project(2016zzts111)supported by the Independent Exploration and Innovation Program of Central South University,ChinaProject(CSUZC201715)supported by Open-End Fund for the Valuable and Precision Instruments of Central South University,China
文摘The adsorption behavior and mechanism of Bi（Ⅲ） ions on the rutile-water interface were investigated through micro-flotation, Zeta potential measurement, adsorption amount measurement and X-ray photoelectron spectroscopy（XPS）. According to the results of micro-flotation, Bi（Ⅲ） ions could largely improve the rutile flotation recovery（from 62% to 91%）, and they could increase the activating sites and reduce the competitive adsorption between nonyl hydroxamic acid negative ions and OH-ions, which determined that Bi（Ⅲ） ions were capable of activating rutile flotation. The adsorption of Bi（Ⅲ） ions onto the rutile surface led to the shift of Zeta potential into the positive direction, which was good for the adsorption of nonyl hydroxamic acid anions. In addition, the results of XPS indicated that the chemical environment around Ti atom had not changed before and after the adsorption of Bi（Ⅲ） ions. Based on the adsorption mechanism of Bi（Ⅲ） ions, it was deduced that firstly Bi（Ⅲ） ions occupied the vacancies of the original Ca^2＋, Mg^2＋ and Fe^2＋ ions on the rutile surface; secondly Bi（Ⅲ） ions covered on the rutile surface in the form of hydroxides.
基金support from the National Natural Science Foundation of China(No.22275120)the Science and Technology Commission of Shanghai Municipality(No.22520711600).
文摘Luminescence quench is common in overdoped upconversion nanoparticles.Various methods have been proposed to counteract the adverse effects of concentration quenching on luminescence,but in upconversion nanoparticles that are highly doped with both sensitizers and activators,the factors that contribute to the diminishing of the emission cannot be summarized by a single cause.Herein,a core-shell design is used to spatially separate the sensitizer(Yb^(3+))and activator(Er^(3+))and to modulate the emission by changes in the distribution position as well as the concentration of the dopant ions in order to probe the factors affecting the luminescence.When the sensitizer ions are located in the core,the luminescence intensity of the nanoparticles is significantly weaker than that of the other distribution,which implies that the effect of sensitizer and activator on luminescence in the highly doped state has a different and more complex mechanism.The intensity of the emission is more affected by Yb^(3+)than Er^(3+),which includes not only the self-quenching of Yb^(3+),but also the dominance in the Yb^(3+)-Er^(3+)cross-relaxation.In this finding may provide new ideas for revealing the reasons for the diminished luminescence of highly doped upconversion nanoparticles and thus for enhancing luminescence.
基金Project supported by the National Natural Science Foundation of China(U21A2068,11974142,11874181,12204248)the Fundamental Research Funds for the Central UniversitiesJiangsu Funding Program for Excellent Postdoctoral Talent(2022ZB399)。
文摘The toxicity of lead ions has become the severe challenge for the all-inorganic lead halide p erovskite materials,although some works have rep orted the lead-free perovskite nanocrystals(NCs),the photoluminescence quantum yield(PLQY)of these materials is still unsatisfactory.Meanwhile,because the halogen ions can be easily exchanged,the controllable multicolor emission in perovskite NCs is difficult to realize in current reports.In this work,we introduced lanthanide ions into lead-free Cs_(3)Sb_(2)Cl_(9) perovskite NCs.Benefitting from the energy transfer between Cs_(3)Sb_(2)Cl_(9) perovskite NC host and lanthanide ions,the multicolor emission was realized.Based on controlling the doping concentration of Tb^(3+)and Eu^(3+)ions,the white light emission under UV excitation would be turned easily in the Tb^(3+)/Eu^(3+)codoped NCs.In addition,efficient energy transfer from perovskite NCs to Tb^(3+)or Eu^(3+)ions is beneficial to improving the optical properties of lead-free perovskite NCs,resulting in maximum PLQYs of red,green and white light emission of 22.6%,19.7%and 28.5%,respectively.Finally,a white light emitting device(WLED)was fabricated with a power efficiency of 18.5 lm/W,which presents the Commission Internationale de l'Eclairage(CIE)of(0.33,0.35).
基金supported by the National Natural Science Foundation of China(No.50608056)the Hong Kong Research Grants(No.HKUST6106/03E)the Program for Young Excellent Talents in Tongji University in part(No.2006KJ033).
文摘Humic substances are ubiquitous redox-active organic compounds of environment. In this study, experiments were conducted to determine the reduction capacity of humic acid in the man-ix of bromate and Fe（Ⅲ） solutions and the role of Fe（Ⅲ） in this redox process. The results showed that the humic acid regenerated Fe（Ⅱ） and reduced bromate abiotically. The addition of Fe（Ⅲ） could accelerate the bromate reduction rate by forming humic acid-Fe（Ⅲ） complexes. Iron species acts as electron mediator and catalyst for the bromate reduction by humic acid, in which humic acid transfers electrons to the complexed Fe（Ⅲ） to form Fe（Ⅱ）, and the regenerated Fe（Ⅱ） donate the electrons to bromate. The kinetics study on bromate reduction further indicated that bromate reduction by humic acid-Fe（Ⅲ） complexes is pH dependent. The rate decreased by 2-fold with the increase in solution pH by one unit. The reduction capacity of Aldrich humic acid was observed to be lower than that of humic acid or natural organic matter of Suwanne River, indicating that such redox process is expected to occur in the environment.
