Eu（Ⅲ） Indirect Probe to Investigate Interaction of DOPA （3, 4, Di-Hydroxyphenylalanine） and Dopamine （3, 4-Dihydroxy Phenyl Ethyl Amine） Using Electrochemical Methods

Eu（ Ⅲ ） can be utilized as an indirect electrochemical probe to investigate the interaction of bio-molecules such as DOPA and Dopamine with Ca（ Ⅱ ） in vitro. The interaction of DOPA and Dopamine with Eu（ Ⅲ ）-Eu（ Ⅱ ） redox pair was investigated by electrochemical techniques. Both the neurotransmitters are structurally related and undergo interaction with Eu （Ⅲ ）. Eu （ Ⅲ ） coordinates with DOPA and Dopamine through five-member chelate tings via carboxylic oxygen and amino nitrogen. The electrode kinetic parameters viz, transfer coefficient （αna）, diffusion coefficient （D）, forward heterogeneous rate constant （ k^0 fh） were evaluated for Eu（ Ⅲ ）-DOPA/Eu（ Ⅲ ）-Dopamine. The results obtained were used to investigate the nature of interaction of Eu （Ⅲ） with muhi-donor biomolecules. The possible mechanism was also proposed.     

Structure of Complexes of Lanthanides with N,N''-Dimethyl-3-Oxa-Glutaramic Acid

A new stripping agent N,N-dimethyl-3-oxa-glutaramic Acid (DOGA) was used in TRPO process to simplify the TRPO process. The structures of the complexes of the DOGA with Eu(Ⅲ), Nd(Ⅲ), La(Ⅲ) were characterized with extended X-ray absorption fine structure spectroscopy (EXAFS), infrared spectra (IR) and mass spectra (MS). The molecular formula of the complexes of Eu(Ⅲ) and Nd(Ⅲ) is deduced to be M(DOGA)3, and only La(Ⅲ) can form the complex HM(DOGA)4 under condition of high consistency of the DOGA. The coordination number of Ln(Ⅲ) in the complexes is 8, and all of coordinated donor atoms are O atoms. For Eu(Ⅲ), Nd(Ⅲ), the coordination numbers of O atom in the first coordination shell is 6 and the average coordination bond lengths of Ln-O are 0.240 nm, 0.244 nm respectively, while the numbers of the second O shell are 2.4, and the average coordination bond lengths of Ln-O are 0.260 nm, 0.262 nm. For La(Ⅲ), the coordination numbers of O atom in the first coordination shell is 6 and the average coordination bond lengths of La-O are 0.258 nm, while the number of O atom in the second coordination shell is 4.4, and the average coordination bond length of La-O is 0.28 nm. The results of IR and MS show that there is no water coordinating with Ln(Ⅲ) in the complexes.     

Effect of pH on sorption for RE（Ⅲ） and sorption behaviors of Sm（Ⅲ） by D152 resin

The pH dependent sorption of rare earth ions （La（Ⅲ）, Ce（Ⅲ）, Pr（Ⅲ）, Nd（Ⅲ）, Y（Ⅲ）, Sm（Ⅲ）, Eu（Ⅲ）, Gd（Ⅲ）, Tb（Ⅲ）, Dy（Ⅲ）, Ho（Ⅲ）, Er（Ⅲ）, Lu（Ⅲ）, and Yb（Ⅲ）） from HAC-NaAC buffer solution at 298 K by D152 resin containing -COOH function groups were presented. The sorption behaviors of D152 resin for Sm（Ⅲ） were discussed as an example. The effects of operational conditions such as pH, temperature, and contact time were studied. The statically saturated sorption capacity was 510 mg/g resin at pH 6.70 in HAc-NaAc medium at 298 K. The sorption behaviors obeyed the Freundlich isotherm. The capacity value for column study was obtained by graphical integration as 495 mg/g resin. Thomas model was applied to experimental data to predict the breakthrough curve and to determine the characteristic parameters of the column useful for process design.     

Synthesis,spectroscopic characterization,and thermal decomposition kinetics of some lanthanide（Ⅲ） nitrate complexes of 2-（N-o-hydroxyacetophenone） amino-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene

Complexes of La（Ⅲ）, Ce（Ⅲ）, Pr（Ⅲ）, Nd（Ⅲ）, Sm（Ⅲ）, Eu（Ⅲ）, Gd（Ⅲ）, Dy（Ⅲ）, Yb（Ⅲ）, and Lu0ID with 2-（N-o- hydroxyacetophenone）amino-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene （HAAT） formed by the condensation of o-hydroxyacetophenone and 2-amino-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene were synthesized and characterized on the basis of elemental analyses, molar conductance measurements, magnetic susceptibility data, UV-Visible, IR, and NMR spectral studies. The spectral data revealed that the ligand acted as a neutral tridentate coordinating to the metal ion through ONO donor sequence. A coordination number nine was proposed for the complexes. Thermal decomposition studies of the ligand and lanthanum（Ⅲ） complex were carried out and kinetic parameters were calculated using Coats-Redfem equation. The decomposition reactions followed random nucleation mechanism with one nucleus on each particle.     

Structure of Complexes of Lanthanides with N, N＇-Dimethyl-3-Oxa-Glutaramic Acid

A new stripping agent N, N-dimetbyl-3-oxa-glutaramic Acid (DOGA) was used in TRPO process to simplify the TRPO process. The structures of the complexes of the DOGA with Eu(Ⅲ), Nd(Ⅲ), La(Ⅲ) were characterized with extended X-ray absorption fine structure spectroscopy (EXAFS), infrared spectra (IR) and mass spectra (MS). The molecular formula of the complexes of Eu( Ⅲ ) and Nd( Ⅲ ) is deduced to be M(DOGA)3, and only La( Ⅲ ) can form the complex HM(DOGA)4 under condition of high consistency of the DOGA. The coordination number of Ln( Ⅲ ) in the complexes is 8, and all of coordinated donor atoms are O atoms. For Eu( Ⅲ ), Nd( Ⅲ ), the coordination numbers of O atom in the first coordination shell is 6 and the average coordination bond lengths of Ln - O are 0.240 nm, 0.244 nm respectively,while the numbers of the second O shell are 2.4, and the average coordination bond lengths of Ln - O are 0.260 nm,0. 262 nm. For La( Ⅲ ), the coordination numbers of O atom in the first coordination shell is 6 and the average coordination bond lengths of La - O are 0.258nm, while the number of O atom in the second coordination shell is 4.4, and the average coordination bond length of La - O is 0.28 nm. The results of IR and MS show that there is no water coordinating with Ln( Ⅲ ) in the complexes.     

Intercalation Assembly, Characterization and Luminescent Properties of Novel Supramolecular Composite Materials, Tb （ Ⅲ ） Complex with Tetrapodal Ligand- Montmorillonite

Two kinds of Tb（ Ⅲ ） complexes with tetrapodal ligand, [TbL（NO3）]^3＋ and [TbL]^3＋ （L： 1,1, 1＇, 1＇-tera （ 2-pyridinecarboxylester ）-di （ trimethylpropane）） were intercalated into the interlayer space of montmorillonite （MT） by ion exchange and coordination reaction of L with the Tb^3＋ ion existing in the interlayer space of Tb-MT respectively. The obtained luminescent supramolecular composite materials, [ TbL （NO3） ]^2＋-MT and [TbL]^3＋-MT were characterized by elemental analysis, XRD, FT-IR, UV-vis and thermal analysis. At the same time, the luminescent properties of the materials were also studied. The results show that the intercalated materials with regular layered structure, good thermal stability and the interlayer spacing （d001） approximates to the size of the complex ions which are located in the interlayer space of MT in the form of a monolayer.     

Synthesis,spectroscopic characterization,DNA cleavage and antibacterial studies of a novel tridentate Schiff base and some lanthanide（III） complexes

A novel potential tridentate Schiff base was prepared by condensing equimolar quantities of 2-hydroxyacetophenone and 2-aminopyrimidine in methanol. This ligand was versatile in forming a series of complexes with lanthanide ions such as La（III）, Pr（III）, Nd（III）, Sm（III）, Gd（III）, Dy（III） and Yb（III）. The ligand and the metal complexes were characterized through elemental analysis, molar conductance, UV-Visible, IR, 1H NMR, and mass spectral studies. The spectral studies indicated that the ligand was coordinated to the metal ion in neutral tridentate fashion through the azomethine nitrogen, one of the nitrogen atoms in the pyrimidine ring and the phenolic oxygen without deprotonation. Thermal decomposition and luminescence property of lanthanum（III） complex were also examined. The X-ray diffraction patterns showed the crystalline nature of the ligand and its lanthanum（III） complex. The DNA cleavage studies of the ligand and the metal complexes were carried out and it was observed that the lanthanum（III） and neo-dymium（III） complexes cleaved the pUC19 DNA effectively. The ligand and the metal complexes were screened for their antibacte-rial activities. The metal complexes were found to be more potent bactericides than the ligand.     

Studies on some lanthanide（Ⅲ） complexes with 4-hydroxyantipyrine

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.     

Microwave assisted synthesis,spectroscopic, thermal,and antifungal studies of some lanthanide（Ⅲ） complexes with a heterocyclic bishydrazone

A bishydrazone formed by the condensation of isatinmonohydrazone and salicylaldehyde reacted with lanthanide（Ⅲ） chloride to form complexes of the type [Ln（HISA）2Cl3], where, Ln=La（Ⅲ）, Ce（Ⅲ）, Pr（Ⅲ）, Nd（Ⅲ）, Sm（Ⅲ）, Eu（Ⅲ）, or Gd（Ⅲ） and HISA= [（2-hydroxybenzaldehyde）-3-isatin]bishydrazone. Both reactions were carried out under microwave conditions. The ligand and the metal complexes were characterized on the basis of elemental analysis, molar conductance, magnetic susceptibility measurements, UV visible, infrared, far infrared, and proton NMR spectral data. The ligand acted as neutral tridentate, coordinating through the carbonyl oxygen, azomethine nitrogen, and phenolic oxygen without deprotonation. The ligand and lanthanum（Ⅲ） complex were subjected to X-ray diffraction studies. The X-ray diffraction pattern of ligand exhibited its crystalline nature and that of the lanthanum（Ⅲ） complex indicated its amorphous character. The thermal decomposition behaviour of the complex, [La（HISA）2Cl3], was examined in the temperature range of 40-800 ℃ using TG, DTG, and DTA. The ligand and the metal complexes were screened for their antifungal activities.     

Study on the adsorption of lanthanum(Ⅲ) from aqueous solution by bamboo charcoal

The adsorption behaviors of La(Ⅲ) ion on bamboo charcoal were investigated with various chemical methods and IR spectrometry. Parameters studied include the effects of pH,average particle size,initial ion concentration,contact time and temperature by batch method. The results showed that bamboo charcoal could remove La(Ⅲ) ions effectively from aqueous solution. The loading of La(Ⅲ) ions was strongly dependent on pH of the medium and the optimal adsorption condition was in HNO3-TEA medium with pH value of 7.20. In the batch system,the modified bamboo charcoal exhibited the highest La(Ⅲ) ion uptake as 120 mg/g at 298 K,at an initial pH value of 7.20. The adsorption kinetics were tested with Lagergren-first-order model and pseudo-second-order model. The adsorption data were conformed to the Langmuir and Freundlich isotherms,and the correlation coefficients had been evaluated. Thermodynamic parameters such as free energy(ΔG) ,which were all negative,indicated that the adsorption of La(Ⅲ) ion onto bamboo charcoal was spontaneous and the positive value of enthalpy(ΔH) showed that the adsorption was endothermic in nature. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design. The characterization of both before and after adsorption of La(Ⅲ) ion on bamboo charcoal was undertaken using IR spectroscopic technique. The results revealed that bamboo charcoal was a good choice as a biosorbent for the recovery of lanthanum from aqueous solution.     

Microwave assisted synthesis, spectroscopy and biochemical aspects of lanthanum(Ⅲ) and praseodymium(Ⅲ) complexes with oxadiazole functionalised dithiocarbazinates

The new lanthanum (Ⅲ) and praseodymium (Ⅲ) complexes of the general formula [Ln(L)3] (Ln=La(Ⅲ) or Pr(Ⅲ); LK=potassium salt of dithiocarbazinates) were prepared by both, conventional thermal and by the use of microwave technology. Elemental analyses, elec-trical conductance, magnetic moment and electronic, infrared, far-infrared, 1H and 13C NMR spectral studies were used to characterize the complexes. The molecular weights of few complexes were determined by FAB-mass spectra. Nephelauxetic ratio, covalency parameter and bonding parameter for these complexes were also calculated. The probable structures of the complexes were proposed. The antifungal and antibacterial activities of the complexes were evaluated. The activities were correlated with the structures of the compounds.     

Solvent extraction of Pr and Nd (III) from chloride-acetate medium by 8-hydroquinoline with and without 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester as an added synergist in heptane diluent

In this paper, solvent extraction of Pr (III) and Nd (III) using 8-hydroxyquinoline in chloride-acetate medium has been systematically investigated. The effect of various parameters, such as equilibrium time, aqueous pH, extractant concentration, acetate ion concentration, chloride ion concentration, and organic solvent, on the extraction has been discussed. The synergistic effect in the mixtures of 8-hydroxyquinoline (HQ) and 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (P507) has been explored, and the largest synergistic enhancement factor has been calculated. The separations of Pr (III), Nd (III) and La (III) by 8-hydroquiloline alone and by mixtures of HQ and P507 have been studied, and the results demonstrate that it is possible to separate Pr (III), Nd (III) and La (III) with the mixtures of HQ and P507. At last, the stripping of Pr, Nd and La (III) has been performed.     

Enhanced adsorption behavior of Nd(III) onto D113-III resin from aqueous solution

An enhanced adsorption and desorption procedure of Nd(III) onto D113-III resin were prepared with various chemical methods.Batch studies were carried out with various pH,contact time,temperature and initial concentrations,and then column studies were conducted.The results showed that the optimal adsorption condition was at pH value of 6.90.The process was fast initially and arrived equilibriumwithin 60 h.The resin exhibited a high Nd(III) uptake as 232.56 mg/g at 298 K.The adsorption data fitted well with p...     

Sensitivity of a solid Eu(III) complex towards acetonitrile vapor: Structural and spectroscopic characterization

The Eu(III) nitrate complex of the meso- N,N′-bis(2-pyridylmethylene)-1,2-(R,S)-cyclohexanediamine ligand was synthesized and characterized by single crystal and powder X-ray diffraction. The crystal lattice of the complex is capable of absorbing and desorbing selectively acetonitrile molecules, at 293 K upon an acetonitrile vapor pressure of ∼0.1 × 10⁵ Pa. This process, which is partially reversible, can be easily followed by both powder X-ray diffraction (P-XRD) and Eu(III) luminescence spectroscopy. The acetonitrile molecule, located in the outer coordination sphere of the metal ion, does not affect the radiative transition probability of ⁵D₀ level of Eu(III) and also it does not activate further non-radiative channels from this level. On the other hand, this molecule is capable of affecting the energy position and intensities of the crystal field components of the ⁵D₀→⁷F₂ transition. The complex in solid form can be considered a promising material for the optical sensing of acetonitrile vapors.     

Ion imprinted cryogel-based supermacroporous traps for selective separation of cerium(III) in real samples

This study demonstrates the preparation and characterization of a novel ion imprinted cryogel which exhibits high affinity and selectivity towards Ce(III) ions in aqueous solutions and bastnäsite ore samples. 2-Hydroxyethyl methacrylate (HEMA) and N-methacryloylamido antipyrine (MAAP) were used as functional monomers for the preparation of Ce(III) imprinted cryogel. The effects of various factors such as initial Ce(III) concentration, flow rate, pH, interaction time and ionic strength on the Ce(III) binding to the prepared ion imprinted cryogels were also studied. The binding equilibrium for Ce(III) is obtained in 30 min at the flow rate of 0.5 mL/min. The maximum binding capacity of the prepared ion imprinted cryogel towards Ce(III) is obtained as 36.58 mg/g at optimum conditions. The selectivity of the prepared ion imprinted cryogel towards Ce(III) in the presence of other possible interfering lanthanide ions such as La(III) and Nd(III) were also performed. The obtained results showed that the prepared ion imprinted cryogel exhibits high selectivity and sensitivity towards Ce(III) ions. The limit of detection (LOD) was found as 50 μg/L.     

Evaluation of D113 cation exchange resin for the removal of Eu(III) from aqueous solution

Batch adsorption experiments were conducted for the adsorption of Eu(III) ions from aqueous solution by D113 resin. The results indicated that D113 resin could adsorb Eu(III) ion effectively from aqueous solution. The adsorption was strongly dependent on pH of the medium with enhanced adsorption as the pH turned from 3.50 to 7.00 and the optimal adsorption condition was in HAc-NaAc medium with pH value of 6.50. The maximum uptake capacity of Eu(III) ions was 290.9 mg/g D113 at 298 K, at an initial pH value of 6.50. The overall adsorption process was best described by Lagergren-first-order kinetics. When Freundlich and Langmuir isotherms were tested, the latter had a better fit with the experimental data. The thermodynamic parameters such as free energy (?G) which were all negative, indicated that the adsorption of Eu(III) ions onto D113 resin was spontaneous and the positive value of enthalpy (?H) showed that the adsorption was endothermic in nature. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design. Furthermore, Eu(III) could be eluted by using 3.0 mol/L HCl solution and the D113 resin could be regenerated and reused.     

罗丹明B与铁(Ⅲ)的荧光猝灭反应及其应用

在pH 10.0的NH_3-NH_4Cl缓冲溶液中,微量Fe(Ⅲ)对罗丹明B的荧光强度具有明显的猝灭作用。实验研究了该猝灭反应并讨论了将其应用于铁(Ⅲ)分析的最佳条件。实验表明,于25mL比色管中,分别依次加入3.00mL罗丹明B溶液、一定量的Fe(Ⅲ)标准溶液、2.00mL pH 10.0的NH_3-NH_4Cl缓冲溶液,用水稀释至刻度,摇匀,用1cm四面透光的石英比色皿进行测定,体系的最大发射波长λem=580nm,最大激发波长λex=550nm。Fe(Ⅲ)的质量浓度在0.004~0.028μg/mL范围内与其对应的荧光猝灭值ΔF呈良好的线性关系,相关系数为0.987 9,方法的检出限为0.003 8μg/mL。将实验体系应用于不同环境水样(矿泉水、山泉水、自来水)中Fe(Ⅲ)的测定,测得结果与原子吸收光谱法(国家水质标准方法GB 11911—1989)基本一致,相对标准偏差(RSD,n=6)为3.5%~7.5%,回收率在99%~106%之间。