Studies on synthesis and fluorescent property of rare earth complexes RE(ABMF)_2AA and copolymers RE(ABMF)_2AA-co-MMA

Four new complexes RE（ABMF）2AA（RE=Sm, Eu, Tb, Dy） were synthesized by the reaction of RECl3·6H2O with acrylic acid（HAA） and 1-（2-furyl）-3-phenyl-1,3-propanedione（ABMF）.The copolymerization of the rare earth complexes with methyl methacrylate was studied by using 2,2-azobis-isobutyronitrile as an initiator.The composition and structure of the four complexes were characterized by elemental analysis, UV-vis and FTIR.The glass transition temperature and molecular weight of the copolymers were determined.Photolu-minescent measurement showed that ligand ABMF could efficiently transfer the energy to Sm^3＋ and Eu^3＋ ions in the complexes and sensitize the luminescence of the rare earth ions, but could not sensitize Tb^3＋ and Dy^3＋ ions.As a result, both Sm^3＋ and Eu^3＋ complexes emitted the characteristic fluorescence of Sm^3＋ and Eu3＋ ions due to the f-f transitions.The four copolymers could emit strong fluorescence of the rare earth ions.

Synthesis, Characterization and Vulcanizing Properties of Rare Earth Complexes with 2-Mercaptobenthiazole

Eight complexes of rare earth with 2 mercaptobenthiazole, RELCl 2·RE(OH) 3· x H 2O (L=2 mercaptobenthiazole, RE= La～Gd, Y, except for Pm, x =0, 2～4), were synthesized in unhydrous ethanol and characterized by elemental analyses, IR spectra and thermal analyses. The results show that the ligand is coordinated to the RE ion through both the exocyclic sulfur and the thiazole nitrogen. The vulcanizing properties of the La complex as accelerator were studied in the traditional tire rubber, which indicate that the cross linked rubber accelerated by the rare earth complex has good physical and dynamic mechanical properties by comparison.

Interaction between Ternary Rare Earth Complexes of Cinnamic Acid and Phenanthroline with DNA by Spectroscopy

The interaction of ternary complexes [RE(phen)(cin)_3(H_2O)](RE= Nd (III),Ce(III),Eu(III))with calf thymus DNA was investigated by electronic absorption spectroscopy, ethidium bromide(EB)-DNA quenching fluorescent spectra and resonance light scattering. All experimental results indicate that the three complexes bind to DNA by the electrostatic mode and the intercalative mode. It is predicted that these complexes show high anticancer activity or other biologic activity.

Luminescent Properties of Bi-Rare Earth Complexes with m-methylbenzoic Acid and 1,10-phenanthroline

The bi rare earth complexes EuTb( m MBA) 6(phen) 2·2H 2O, TbY( m MBA) 6(phen) 2·2H 2O were synthesized by the reaction of RECl 3 with m methylbenzoic acid and 1,10 phenanthroline in ethanol solution, where m MBA=m methylbenzoate and phen=1,10 phenanthroline. The luminescence properties of the title complexes were studied in comparison with the corresponding complexes Eu 2( m MBA) 6(phen) 2·2H 2O and Tb 2( m MBA) 6(phen) 2·2H 2O respectively. The results indicate that the emission intensity from europium ion can be greatly enhanced by the terbium ion, while the emission from terbium ion was strongly quenched by europium ion in EuTb( m MBA) 6(phen) 2·2H 2O; the emission intensity from terbium ion can be greatly enhanced by yttrium ion in TbY( m MBA) 6(phen) 2·2H 2O. The mechanism about the results was discussed.

Study on Luminescence Properties of a Novel Rare Earth Complex Eu(TTA)_2(N-HPA)Phen

A novel rare earth complex Eu（TTA）2（N-HPA）Phen （TTA = thenoyltrifluoroacetone, N-HPA = N-phenylanthranilic acid, and phen = 1,10-phenathroline ）, which contains three different ligands, was synthesized. The Eu complex was blended with poly N-vinylcarbazole （PVK） in different weight ratios and spin coated into films. The luminescence properties of films were investigated and energy transfer between PVK and the complex was discussed. Multilayer structural devices consisting of ITO/PVK： Eu （TTA）2 （N-HPA） phen/BCP/Alq3/Al were fabricated with PVK ： Eu （TTA）2（N-HPA） as light-emitting layer. Increasing the concentration of Eu in the PVK thin film would inhibit the emission of PVK to different degrees. Finally, the pure red luminescence of europium（ Ⅲ ） was observed when the doping weight ratio was approximately 1 ： 5, which indicated an effective energy transfer from PVK to rare earth complex.

Preparation, Characterization and Luminescent Properties of MCM-41 Type Materials Impregnated with Rare Earth Complex

Hybrid materials incorporating Eu-(TTA)(3). 2H(2)O (7hereafter designated as Eu-TTA, with TTA: thenoyltrifluoroacetone) in unmodified or modified MCM-41 by 3-aminopropyl-triethoxysilane (APTES) were prepared by impregnation method. The obtained materials were characterized using X-ray diffraction (XRD), IR and diffuse reflectance spectroscopy and luminescence spectra. All the hybrid samples exhibited the characteristic emission bands of EU3+ under UV light excitation at room temperature, and the excitation spectra showed significant blue-shifts compared to the pure rare-earth complex. Although the red emission intensity in the modified hybrid was almost the half of the red emission intensity in the pure Eu-TTA complex at room temperature, the hybrid showed a much higher thermal stability due to the shielding character of the MCM-41 host.

Synthesis and Photoluminescence Properties of Rare Earth Complexes with 3-Allyl-2, 4-Pentanedione

In order to combine the merits of rare earth organic complexes with excellent material performances of polymers, a polymerizable chelating agent, 3-allyl-2, 4-pentane dione (APD), was synthesized by phase transfer catalysis and its rare earth complexes were prepared. The compounds were characterized by EA, IR and (()~1H NMR.) Their UV spectra and fluorescence spectra were investigated. The effects of allyl on the luminescence properties of the complexes were studied. The results show that the sensitization of APD is changed by allyl in comparison with that of acetyl acetone (acac), and it becomes an ideal novel ligand of Eu. In addition, intramolecular energy transfer mechanism in the luminescence process in the complexes was also discussed in detail.

An Encapsulation of the Rare Earth Complex in Modified Mesoporous Molecular Sieve MCM-41

The encapsulation of a rare earth (RE) complex Eu(DBM)(3)phen in modified S1-MCM-41 with 3-aminopropyltriethoxysilane is reported for the first time. The luminescence intensity of the RE complex in the modified Si-MCM-41 is about 9 times as strong as in unmodified Si-MCM-41 and the luminescence of the RE complex in the modified SI-MCM-41 has good color purity.

Syntheses and Infrared Spectra of Rare Earth Complexes with Diethyl Phosphate

The title complexes Ln(DEP),(Ln=La,Sm,Eu,Ho and Yb)were synthesized by reaction of triethyl phosphate with trivalent rare earth chlorides.The mechanism of thermo-decomposition of the complexes has been studied.According to their IR spectra,the residues of the thermo-decomposition of the complexes were identified as Ln(PO_3)_3.Their IR spectra were measured and principal IR bands were assigned.The experimental results of the IR spectra of the complexes show that the title complexes have the same coordination form and mo- lecular configuration as rare earth,e.g.Sm,complex with dimethyl phosphate(Sm(DMP)_3).Each of the rare earth ion links three rare earth ions nearby through double“O-P-O”bridges to form a special network of rings-linking-rings,each of which consists of twenty-four atoms.The Ln-O bond is principally ionic.

The Luminescence Properties and Intramolecular Energy Transfer of Rare Earth Complexes with Aromatic Carboxylic Acids

The triplet state energies of para aminobenzoic acid and nicotinic acid were determined by means of low temperature phosphorescence spectrometry. The energy matches between them and the resonant emitting energy levels of Eu 3+ , Tb 3+ , Sm 3+ , Dy 3+ were studied. The intramolecular energy transfer processes from the two aromatic carboxylic acid ligands to rare earth ions were also discussed on the basis of the measurement results of luminescence intensities, lifetimes and quantum efficiencies.

Multiple Energy Transfers in Rare Earth Complex-Doped SiO_2 Spheres

Silica spheres doped with Eu （TTFA）3 and/or Sm（TTFA）3 were synthesized by using the modified Stober method. The transmission electron microscope image reveals that the hybrid spheres have smooth surfaces and an average diameter of about 210 nm. Fluorescence spectrometer was used to analyze the fluorescence properties of hybrid spheres. The results show that multiple energy transfer processes are simultaneously achieved in the same samples co-doped with Eu （TTFA）3 and Sm（TTFA）3, namely between the ligand and Eu^3＋ ion, the ligand and Sm^3＋ ion, and Sm^3＋ ion and Eu^3＋ ion. Energy transfer of Sm^3＋→Eu^3＋ in the hybrid spheres leads to fluorescence enhancement of Eu^3＋ emission by approximately an order of magnitude. The lifetimes of the hybrid spheres were also measured.

Study of Electroplex Emission from Organic Electroluminescent Devices with Rare Earth Complex

A novel organic electroluminescent device was made with the structure of ITO/PVK：Tb0.5Eu0.5（TTA）3 Dipy/ BCP/Alq3/Al（a） which utilized the rare earth complex Tb0.5Eu0.5（TTA）3 Dipy as the emitting layer. When it was driven under a direct electric field, 612 nm emission from EU^3＋ and 410 nm emission from PVK were observed. In addition, in the EL spectrum a new peak at 490 nm appeared. From the analysis of different devices, the mechanism of the new emission was studied. It was concluded that the new emission was the electroplex originating from the interface between the ligand （TTA）3Dipy and BCP.

Synthesis, Characterization and Luminescence Properties of Rare Earth Complexes with Bis(Pyridinyl-Amide)

A ligand, N^1, N^4-di （ pyridin-2-yl ） succi- namide （L） and its lanthanide（ IH ） complexes （RE = La, Eu, Tb, Gd, Yb ） were synthesized and characterized in detail. The results indicate that the composition of the binary complexes is determined as [ REL （H2O）2（NO3）2] NO3, that the complexes are 1 ： 1 electrolytes in DMF, and that the Tb^3＋ complex has brightly green fluorescence in a solid state. At the same time, the energy levels of the excited triplet states for the six ligands were determined to be 22989 -1 cm . The fact that the ligand sensitize Tb^3＋ complexes was explained by the relative energy gap between the lowest triplet energy level of the ligand （T） and ^5Dj of Tb^3＋ or Eu^3＋ . When 2000 cm^-1 〈 △E（T-^5D4） 〈 3000 cm^-1, the luminescent intensity of the Tb^3＋ complex is stronger. When 3000 cm^-1〈 △E （T-^5D1）, the luminescent intensity of the Eu^3＋ complex is weak- er or close to nil. This means that the triplet energy level of the ligand is a chief factor that dominates RE^3＋ luminescence.

Preparation and Characterization of Polymer－Supported Rare Earth Complexes

he polymers containing different ligand groups of atoms(mainly O,N,and S)and their rare earth complexes were prepared,characterized and classified based on the type of metal-ligand bonding. The catalytic activities of the complexes are briefly discussed.The polymer- supported rare earth complexes shwed much greater activities than the correspond- ing complexes with a low molecular weight.

Synthesis, Catalysis of Rare Earth Complexes with Aliphatic Noncyclic Polyether-Amino Acid Schiff Base

Eleven new rare earth complexes with aliphatic Schiff base, condensed from diglycol aldehyde and bis-arginine, were synthesized and characterized. They are confirmed as Ln （H2DAAR） （NO3）3·7H2O （ Ln = La, Pr, Nd, Gd）, Ln3 （H2DAAR）2（NO3）9·5H2O （Ln= Dy, Y）and Ln2（H2DAAR）（NO3）6·3H2O （Ln = La, Nd, Sm, Gd）, Ln3（DAAR） （NO3）7·4H2O （Ln = Dy, Yb, Y） respectively under different molar ratios of metal to ligand （DAAR = diglycol aldehyde bis-arginine）. The present paper deals with a synthetic method and catalytic properties of obtained complexes. The result shows that proper pH value is important for synthesis of the complexes and compositions of the lighter and the heavier rare earth complexes are different under the same reaction condition. Some new complexes obtained have proved their catalytic activity and 80% conversion with the viscosity-average molecular weight 230,000 for the polymerization of methyl methacrylate （MMA） without addition of any cocatalyst.

Preparation and Characterization of Layered Compound Zirconium Bis(monohydrogenphosphate) Intercalated with Rare Earth Complex

Layered compound zirconium bis(monohydrogenphosphate)(alpha-ZrP) intercalated with rare earth complex Eu(DBM)(3)phen was prepared. The pre-intercalation of p-methoxyaniline into alpha-ZrP makes the interlayer separation large enough to exchange PMA with europium complex, thus, the luminescent assembly was prepared. This was confirmed by X-ray diffraction, UV-visible spectra and elemental analysis. The fluorescence spectra and lifetime of the assembly were also presented.

The Thermodynamic Property of Rare Earth Complexes with L-Threonine

In this paper the stability constants and thermodynamic parameters for complexes of rare earth elements with L-threonine have been measured systematically by potentiometry and calorimetry at 25℃ and ionic strength of 0.15 mol/L(NaCl).The thermodynamic values for protonation of the anion of L-threonine have been obtained.The dependence of stability,enthalpy and entropy change of the complex upon atomic number of cation is investigated,and the coordination of L-threonine to rare earth is also discussed in detail.

STUDIES ON RARE EARTH COMPLEXES WITH CROWN ETHERS ⅩⅧ——Synthesis,Characterization and Crystal Structure of[Sc(NO_3)_3(H_2O)_2]·(15-Crown-5)

The single crystal of the complex [Sc(NO_3)_3(H_2O)_2]·(15C5) has been prepared in acetonitrile.The new complex has been characterized by elemental analysis,IR spectra,solubility and molar conductance measurements.The structure of the complex is determined by single crystal X-ray diffraction analysis.

Study on Electronic Structure of Rare Earth Complex with Dioxygen

The electronic structure and chemical bonding of[Ce(CO_3)_3O_2]_2^(8-) have been studied by INDO (Intermediate Neglect of Differentiated Overlap)method in this paper.The results obtained show that the HOMO of[Ce(CO_3)_3O_2]_2^(8-) is mainly composed of the anti-bonding π orbitals of the pcroxide ion(O_2^(2-)) and the LUMO is mainly composed of the 4f orbitals of the Ce(Ⅳ).The peroxide ion coordinates to ceric ion by means of σ and π dative bonds.After coordination the O-O bond of the peroxide ions is strengthened.By comparison with cerous complexes,the contribution of the 4f orbitals to bonding increases in the ceric com- plex.

ELECTRIC PROPERTY AND STRUCTURE OF EOSIN B,ROSE BENGAL,EOSIN 10B (PHLOXINE B) AND THEIR RARE EARTH COMPLEXES

The electric property and structure of some fluorescein derivatives and their rare earthcomplexes have been reported before.In order to investigate the effect of differentsubstituents on the electric property,the change of resistivity with temperature of eosin B(disodium salt of dibromodinitrofluorescein),rose bengal (disodium salt of tetrachlorotetraiodofluorescein),eosin 10B (dipotassium salt of dichlorotetrabromofluorescein) andtheir complexes with La(Ⅲ),Ce(Ⅲ),Gd(Ⅲ) and Y(Ⅲ) is studied in this paper.