Eu(Ⅲ) complexes involving 1,3,5-triazine diphosphine oxides

The 1,3,5-triazine diphosphine oxide ligands with donor-acceptor properties formed strong complexes with europium（Ⅲ） ion in acetonitrile. Spectrophotometric titrations and mass spectra indicated that two ligands coordinated to one europium ion. The stability constants varied from 11.64 to 14.60 （log 13）. Binary complexes exhibited rather weak luminescence in solution. 1,3,5-triazine diphosphine oxides engaged as co-ligands in Eu（Ⅲ） （2-thenoyltrifluoroacetonate）3 complex contributed to the overall photoluminescence and allowed for excitation with longer wavelengths than the parent complex.

Synthesis of Eu(Ⅲ) and Tb(Ⅲ) Complexes with New Aryl Amide Type Tetrapodal Ligand and Their Luminescence Properties

A new aryl amide type tetrapodal ligand L (1, 1, 1, 1 tetrakis-{[(2 benzylaminoformyl) phenoxyl]methyl}methane) and its europium and terbium nitrate complexes were synthesized. The luminescence properties of these complexes were also studied.

Luminescence Properties of Europium and Terbium Complexes with Pyridine or Bipyridine Linked Oligothiophene Ligand

With an aim to develop novel luminescence materials, europium and terbium complexes of 2, 5-(2-thiophene)-pyridine (TPY), 5, 5′-bis(5-(2, 2′-bithiophene))-2, 5-pyridine (B2TPY) and 5, 5′-bis(5-(2, 2′-bithiophene))-2, 2′-bipyridine (B2TBPY) were synthesized, and their luminescence properties were studied. The complexes exhibited ligand-sensitized emission, which was typical of Eu(Ⅲ) and Tb(Ⅲ) ions. The excitation spectra of Eu(Ⅲ) and Tb(Ⅲ) complexes with TPY (or B2TPY or B2TBPY) show similar bands as these with the ligands. It suggests that, the excitation energy is absorbed by TPY or B2TPY or B2TBPY, the energy transfers from its excited single state to its triplet state, and finally transfers from the ligands to Eu(Ⅲ) and Tb(Ⅲ) ions. The luminescence of Eu(Ⅲ) and Tb(Ⅲ) ions in the TPY or B2TPY or B2TBPY complexes indicates that the metal ions are efficiently excited by the absorbed energy from excitation of the ligands.

Study on Adsorption Behavior of Rare Earth Complexes on Nanometer-Size Titanium Dioxide with ICP-AES

A new method of using nanometer TiO 2 as solid phase extractant coupled with ICP AES was proposed for speciation of rare earth elements. The adsorption behavior of rare earth complexes on nanometer TiO 2 was investigated. Effect of pH value, contact time, elution solution and interfering ions on the recovery of the rare earth complexes were studied. A quantitative recovery (>90%) was found in the pH range of 4～9.0 for Eu citric, 4.5～9.0 for Eu oxine and Eu HIBA, and 6.5～9.0 for Eu 3+ . Eu EDTA can not be adsorbed in the pH range studied. There is large difference in the adsorption behavior on nanometer TiO 2 between rare earth element and its complexes. The possibility of application of nanometer TiO 2 on the speciation of rare earth element was explored.

Kinetics Study on the Thermal Decomposition of Europium p-methyl-benzoate Complex with 1,10-penanthroline under Non-isothermal Con-ditions

The thermal decomposition reaction of Eu-2(p-MBA)(6)(PHEN)(2) (p-MBA=CH3C6H4COO, methylbenzoate; PHEN=C12H8N2, 1,10-phenanthroline) was studied in a static atmosphere using TG-DTG method. The thermal decomposition process of the complex was determined and its kinetics was investigated. Kinetic parameters were obtained from the analysis of TG-DTG curves by means of the Achar method and the Madhusudanan-Krishnan-Ninan (MKN) method. The most probable mechanism functions of the thermal decomposition reaction for the first stage are: f(alpha) =(1-alpha)(2), g(alpha) = (1-alpha)(-1)-1. The activation energy for the first stage is 255.18 kJ/mol, the entropy of activation DeltaS is 227.32 J/mol and the Gibbs free energy of activation DeltaG is 128.04 W/mol.

Luminescence intensification of lanthanide complexes by silver nanoparticles incorporated in sol-gel matrix

We present how the luminescence of europium RR-2-P-oxides complexes can be increased by interaction of electronic levels of the complex with the radiation field of silver nanoparticles （NPs）. The procedure by which silver NPs are formed in a sol-gel polyurethane matrix precursor was elaborated. The formed Ag NPs were combined with Eu complex incorporated in ormocer matrix. The emission spectra of the complexes without silver NPs were compared with spectra of the same complexes with addition of silver NPs. As the result of the interaction of the electronic levels of lanthaaide ligands with silver plasmons, dramatic increase of luminescence was observed.

Synthesis, Crystal Structure and Luminescent Property of an Eu^(3+) Complex

A new Eu（Ⅲ） complex, {[Eu（tta）2（C2H5OH）（NO3）]2（bmp）}·bmp（tta = 2-thenoyltrifluoro- acetonate, bmp = 2,2＇-bipyrimidine）, has been synthesized and characterized by elemental analysis, IR, luminescence and single-crystal X-ray diffraction analysis. The complex crystallizes in the monoclinic P21/n space group, with a = 11.894（6）, b = 14.235（8）, c = 19.078（10） A, β = 103.423（9）°, V = 3142（3） A3, Z = 2, Mr = 1721.10, Dc = 1.819 g/cm^3, F（000） = 1696, the final R = 0.0452 and wR = 0.1398 for 5375 observed reflections with I 〉 2σ（I）. In the complex, each Eu（Ⅲ） ion is coordinated with four oxygen atoms from two tta ligands and two nitrogen atoms from a bmp ligand, three oxygen atoms from one NO3- anion and one ethanol molecule, forming a distorted tricapped trigonal prism geometry. Luminescence measurement indicates that the europium complex is a strong red emitter in the solid state at room temperature.

Interaction between Eu(bpy)_3^(3+) Complex and DNA by Fluorophotometry

The interaction of complex Eu(bpy)_3 (3+) with DNA was studied by fluorophotometry. The binding constant ( K ) and size ( n ) of the binding site were calculated according to the changes of the fluorescent intensity at the adding process of DNA. The model for the complex Eu(bpy)_3 (3+) interacted with DNA solution is found to be electrostatic action. The system Eu(bpy)_3 (3+)-DNA was studied by the voltammetry. The interaction of the complex Eu(bpy)_3 (3+) with the calf thymus DNA was investigated by fluorophotometry,then K and n were obtained.

Synthesis,Characterization,Optical Property and Bioactivity of the Eu(Ⅲ)Complex with Aromatic Carboxylic Triazole

A novel complex{[Eu（H;TIA）(C;O;);（H;O）;]·H;O};of Eu（Ⅲ）with aromatic carboxylic triazole(H;TIA=5-（4H-1,2,4-triazol-4-yl）isophthalic acid,H;C;O;=oxalic acid)was hydrothermally synthesized and characterized by IR,UV-Vis,emission spectra and optical activity,and its crystal structure was determined.It crystallizes in triclinic system,space group P1 with a=7.4452（13）,b=10.776（2）,c=11.286（2）?,α=110.546（3）°,β=106.604（3）°,γ=99.031（3）°,V=486.0,GOOF=1.096,the final R=0.0196 and w R=0.0527 for 3081 observed reflections with I≥2σ（I）,R=0.0209 and wR=0.0535 for all data with（Δ/σ）;=0.001,（Δρ）;=0.48 and（Δρ）;=–0.46 e·?;.The natural bond orbital（NBO）charges,electrostatic potential（ESP）and frontier orbital of this complex were also analyzed.The results of anti-bacterial activity against Gram positive（S. aureus）and Gram negative（E. coli）bacteria reveal that the studied complex possesses a moderate inhibiting effect,and the inhibition effect on E.coli is better.

Preparation and spectroscopic, and thermal decomposition kinetic studies of europium(Ⅲ) complex [Eu(HNBD)_3] (HNBD: 1-(6-hydroxy-1-naphthyl)-1,3-butanedione)

The complex of Eu（IH） with 1-（6-hydroxy- 1-naphthyl）- 1,3-butanedione （HNBD） was prepared for the first time and characterized by elemental analysis, IR, UV, fluorescence spectrum, and DTA-TG-DTG techniques. The IR and UV-visible spectra showed that Eu（Ⅲ） ion was coordinated to the HNBD ligand. The fluorescence spectrum showed the presence of Eu^3＋ characteristic emission. The TG-DTA-DTG curves showed that the thermal decomposition of the anhydrous complex was a two-stage process and the final residue was Eu2O3. The thermal decomposition kinetic parameters of the complex were evaluated from TG-DTG data by using three kinds of integral methods （Coat-Redfem equation, Horowitz and Metzger equation, Madhusudanan-Krishnan-Ninan equation）. The kinetic parameters of the first stage are E^＊ = 164.02 kJ.moll, A = 1.31 × 10^15 s^-l, AS^＊= 42.27 J·K^-l·mol^-l, △H^＊ = 159.51 kJ·mol^-l, △G^＊= 136.54 kJ·mol^-l, and n = 3.1, those of the second stage are E^＊= 128.52 kJ·mol^-l, A = 1.44× 106 s^-1, △S^＊= - 136.89 J·K^-l·mol^-l, △H^＊ = 120.41 kJ·mol^-l, △G^＊= 283.85 kJ·mol^-l, and n = 1.1.

Synthesis,characterization and fluorescence of N,N'-BIS (6-metyl-2-pyridinecarboxylamide-N-oxide)-1,2-ethane and corresponding rare earth (Ⅲ) complexes

A new ligand, N,N-BIS (6-metyl-2-pyridinecarboxylamide-N-oxide)-1,2-ethane (L) and six lanthanide(Ⅲ) complexes (RE=La, Sm, Eu, Tb, Gd, Yb) were synthesized and characterized in detail. The results indicated that the composition of the binary complexes was determined as [REL(H2O)(NO3)2]NO3·nH2O (n=0-2), and the Eu3+ complex had bright red fluorescence in solid state. Three complexes of Eu3+, Tb3+, and Gd3+ with 6-methylpicolinic acid N-oxide (L’) were also synthesized. The relative intensity of sensitized luminescence for Eu3+ increased in the following order: L>L’. The phosphorescence spectra of the Gd3+ complexes at 77 K were measured. The energies of excited triplet state for the ligands were 20704 cm-1 (L) and 20408 cm-1 (L’). The facts that the ligands sensitized Eu3+ strongly and the order of the emission intensity for Eu3+ complexes were explained by ΔE(T-5D). This meant that the triplet energy level of the ligand was the main factor to influence RE3+ luminescence.

Synthesis of novel europium complexes and their photoluminescence properties

Two novel luminescent Eu（III） complexes with the formulas（NIP）Eu（DBM）3 1 and（ENIP）Eu（DBM）3 2(NIP=2-（naphtha-len-1-yl）-1H-imidazo [4,5-f] [1,10] phenanthroline,ENIP=1-ethyl-2-（naphthalen-1-yl）-1H-imidazo [4,5-f] [1,10] phenanthroline,DBM= dibenzoylmethanato) were successfully synthesized and characterized by IR and elemental analysis.The UV-vis absorption spectra and pho-toluminescence properties of the complexes were investigated,and the irradiation at the absorption band between 300-400 nm of europium complexes either in solution or in the solid state led to the emission of a sharp red band at;10 nm,a characteristic Eu3+ emission due to the transition of 5D0→7F2.Furthermore,the weak emission bands around 587 and 595 nm attributed to 5D0→7F0 and 5D0→7F1 transition were also displayed in the emission spectra.These results demonstrated that the Eu（III） ion was sensitized efficiently by the ligand and displayed photoluminescence with high intensity,narrow half-peak width,and monochromic light.The excited-state lifetimes of 1 and 2 were in the microsecond time scale,but the photoluminescence quantum yield of 2（0.03） was two times higher than that of 1（0.01） which should be at-tributed to the effect of the ethyl substituting in ENIP.

Eu(Ⅲ) complex-doped PMMA having fast radiation rate and high emission quantum efficiency

Three Eu（III） ternary complexes, Eu（hfa-H）3（Phen）, Eu（hfa-H）3（Bipy） and Eu（hfa-H）3（Bath） （hfa = hexafluoroacetylacetonate, Phen = 1,10-phenanthroline, Bipy = 2,2＇-bipyridine, Bath = bathophenanthroline）, were synthesized. Their luminescent properties were studied by incorporating deuterated Eu（III） complexes in a poly（methylmethacrylate） （PMMA） matrix, and the results indicated that luminescent PMMA including Eu（hfa-D）3（Bath） showed promising results for applications to novel organic Eu（III） devices, such as the high-power laser materials. Additionally, all the three Eu（III） complexes exhibited good thermostabilization.

Microstructure and properties of honeycomb composite films containing Eu and Sn

Honeycomb composite films were prepared by breath figure method via a straightforward,one-step process by doping complex containing Eu or Sn into polystyrene-b-poly(acrylic acid) solution.Several key influencing factors,such as the concentration of the block polymer solution,the relative humidity of the environment and the amount of complexes,were investigated to control micropore size and tune film surface properties.The characteristics of the composite films were studied by scanning electron microscopy(SEM),atomic force microscopy(AFM),X-ray diffraction(XRD),ultraviolet and emission spectra.Results indicate that composite films containing Eu have excellent optical performance,and micro-patterned bowl-like SnO_(2) microparticles could be fabricated from composite films containing Sn after being calcined at 600℃ for 5 h.This general approach for the fabrication of honeycomb composite films opens a convenient and effective route to the functional modification of honeycomb films and offers new prospects for the application in miniaturized sensors,micro-reactor and catalysis.

Crystal structure and fluorescence spectrum of the complex [Eu(Ⅲ)(TTA)_3(phen)]

The title complex Eu(Ⅲ)(TTA)3(phen) (where TTA= thenoyltrifluoroacetone monoanion; phen = 1,10-phenanthroline) has been synthesized in mixed solvents of acetone and ethanol (1:1 volume ratio) and its crystal structure has been determined by X-ray diffraction. The complex crystals are triclinic, space group P1(#2) with cell dimensions of a = 1.3241 (2) nm, 6 = 1.5278(4) nm, c = 0.9755(3) nm, α = 92.49 (2)°, β=102.57(2)°, γ = 91.62(2)°, V=1.9268(8) nm3, Z = 2, μ(Mo Kα) = 18.77 cm-1, Dx = 1.720 g/cm3. The coordination geometry of Eu atom is a distorted square antiprism, and the encapsulated structure that can meet the structural requirement of the typical europium luminescent sensor. The fluorescence spectrum suggests that the complex is a strong photoluminescent material.

Polystyrene microsphere-based lanthanide luminescent chemosensor for detection of organophosphate pesticides

Fluorescent microspheres of polystyrene-based Eu（Ⅲ） complexes were prepared from TentaGel resin, 2,6-bisbenzimidazolylpyridine and europium nitrate. The microspheres were characterized by FTIR spectroscopy, elemental analysis, XPS measurements and fluorescence spectroscopy. Characteristic red emission under irradiation of 365 nm light from a hand-held UV lamp was observed for the microspheres either in a solution or solid-state. Fluorescent quenching was observed when the microspheres were exposed to a trace amount of diethyl chlorophosphate （DCP） in the dispersion. The material and property can be potentially used to fabricate chemosensor in the detection of organophosphates.