Synthesis and Luminescence Properties of Ternary Europium Complexes inTitania Matrix in the Presence of Dimethylformamide by a Sol-Gel Process

Thesol-gelmethodoffersanewapproachtothesynthesisofglasses,ceramics,fibersand.compositesrelatedtotheopticalproperties['j.Sincesomelanthanideionspossessgoodlumi-nescencecharacteristicsbasedontheelectronictransiti0nsamongthe4fenergylevels,aseriesofrareearthcompoundshavebeenstudiedforprac-ticalapplicationsasphosphors.SomestudiesonluminescencebehaviorofEuCl3andEu(NO3)3.alt.[z's]adsorbedonporousglasses,dopedintosol-gelderivedhostsandusedasaprobetostudytheenvironmentofEu3 duringthedifferentstages0f…     

Self-polymerization of Eu（TTA）3AA in rubber and their fluorescence effect

A simple europium complex,Eu（TTA）3 AA（TTA=4,4,4-trifluoro-1-（2-thienyl）-1,3-butanedione,AA=acrylic acid） was synthesized by a simple solution method.Then,two kinds of rubber matrix,nitrile-butadiene rubber（NBR） and silicone rubber（SiR） were used as the substrate for Eu（TTA）3 AA to prepare fluorescence composites.The neat Eu（TTA）3 AA complex showed the ability of self-polymerization when it was heated at 145 °C.It was found that the fluorescence intensity of the neat Eu（TTA）3 AA decreased over 70% when the polymerization time was over 25 min at 145 °C.The results also revealed that the polymerizated Eu（TTA）3 AA could be dispersed in nano-scale in two matrices and the luminescent intensities decreased 52% in NBR matrix,and 95% in SiR matrix compared with two relative compounds without crosslinking.To optimize the luminescence intensity of the composites,the Eu（TTA）3 AA polymerization kinetic process in matrix was investigated in detail by controlling the temperature,the crosslinking agent,etc.The results showed that the peroxide could accelerate Eu（TTA）3 AA self-polymerization in the rubber matrix,and therefore improved the dispersion,but not be helpful for the luminescence intensity enhancement.In addition,the relatively higher luminescence intensity in Eu（TTA）3 AA/NBR in comparison to that of Eu（TTA）3 AA/SiR might contribute to the interaction between nitrile group（–CN） in NBR and Eu-complexes,suggesting that the luminescence intensity of the composites also depended on the matrix characteristics.     

Synthesis and Characteristic Study on Complexes of Europium（Ⅲ） and Maleic Acid Doped with Non-Fluorescent Ions

Complex of europium （Ⅲ） with maleic acid, and binuclear complexes of europium（Ⅲ）with maleic acid doped with non-fluorescent ions gadolinium, lanthanum and yttrium, were synthesized. The compositions and structures of complexes were characterized with elemental analysis, single crystal X-ray diffraction, IR and DSC-TG. Fluorescent properties were studied with fluorescence spectrum. The results indicated that the strongest fluorescent complexes were obtained when the ratio of europium and non-fluorescent ion was 8：2. The order of Eu^3＋ fluorescence strengthened by three doped rare earths was Gd^3＋ 〉La^3＋ 〉Y^3＋     

Synthesis and spectroscopic properties of rare earth picrate complexes with a new dinaphthalenelamide

The new ligand N-benzyl-2-{2'-[(benzyl-ethyl-carbamoyl)-methoxy]-dinaphthalene-2-yloxy}-N-ethyl-acetamide (L) and its complexes of rare earth picrates were synthesized. The complexes were characterized by elemental analysis, IR, UV-vis spectra and conductivity measurements. The fluorescence properties of the europium complex in solid state and CHCl₃, ethyl acetone, acetonitrile and DMF were investigated. Under the excitation, the europium complex exhibited characteristic emissions of europium. The lowest triplet state energy level of the ligand indicated that the triplet state energy level of the ligand matched better to the resonance level of Eu(III) than Tb(III) ion.     

Synthesis, Characterization and Fluorescence Properties of Europium, Terbium Complexes with Biphenyl-4-Carboxylic Acid and o-Phenanthroline

Two series of solid complexes of europium and terbium with biphenyl 4-carboxylic acid and phen were synthesized and characterized in this report. Their elemental analysis, molar conductivities and TG-DTA studies indicate that the complexes have the composition of Eu(phen)L3·1/2H2O, Eu0.5RE0.5(phen)L3·1/2H2O; Tb(phen)L3·H2O and Tb0.5RE0.5(Phen)L3·1/2H2O. (RE=Y3 , La3 and Gd3 ; L=biphenyl 4-carboxylic acid; phen=o-Phenanthroline). The studies of their IR, UV 1H NMR and molar conductivities demonstrate that biphenyl 4-carboylic acid is bounded with RE(Ⅲ) ion. Rare earth ions coordinate with two nitrogen atoms of phen molecules directly in these rare earth complexes. The fluorescence spectra and fluorescence lifetimes of the rare earth complexes show that the fluorescent intensity and lifetime of a series of europium complexes are longer than those of the series of terbium complexes as having the some ligands. There are better fluorescent intensity and lifetime of hetero-nuclear rare earth complexes than homo-nuclear rare earth complexes for europium complexes. The fluorescence emission intensity of Eu3 is raised by inert fluorescent rare earth ions (Y3 , Gd3 and La3 ), but in Tb3 hetero-nuclear rare earth complexes the intensity of Tb3 ions are quenched by the inert fluorescent rare earth ions.     

Synthesis, characterization and enhanced luminescence of terbium complexes with 2-pyrazinecarboxylic acid and butanedioic acid by inert-fluorescent lanthanide ions

Ten solid terbium complexes with 2-pyrazinecarboxylic acid (Hpyca) and butanedioic acid (BDAH) were synthesized via coprecipitation method and characterized by elemental, EDTA titration, inductively coupled plasma (ICP), thermogravimetry-differential scanning calorimetry (TG-DSC) and infrared (IR) analyses. The results showed that the complexes had the compositions of Tb(pyca)(BDA)·2H2O, Tb0.5Y0.5(pyca)(BDA)·2H2O, Tb0.5La0.5(pyca)(BDA)·3H2O, Tb0.5Gd0.5(pyca)(BDA)·2H2O, Tb0.7Y0.3(pyca)(BDA)·3H2O, Tb0.7La0.3(pyca)(BDA)·0.5H2O, Tb0.7Gd0.3(pyca)(BDA)·H2O, Tb0.6Y0.4(pyca)(BDA)·2.5H2O, Tb0.6La0.4 (pyca)(BDA)·2.5H2O and Tb0.6Gd0.4(pyca)(BDA)·3H2O. IR spectra indicated that the rare earth ions coordinated with the carboxylic oxygen atoms of Hpyca and BDAH. Luminescence spectra showed that the doped La3+, Y3+ or Gd3+ ions did not affect the luminescence emission peak positions, but remarkably increased the luminescent intensities of terbium complexes. Furthermore, the doped lanthanide complexes showed longer luminescence lifetimes and higher quantum yields than pure terbium complex. The enhanced luminescence efficiencies of Tb3+ ions in the doped complexes might result from the antenna effect of the two carboxylate ligands as well as the decrease of the self-quench of the Tb3+ ions induced by the doped lanthanide ions.     

Preparation and properties of RE3+ doped luminescent co-polymer by solution copolymerization

Bonded type RE3+ doped luminescent co-polymer was synthesized by solution free radical copolymerization. The influence of charge sequence, monomers and co-polymerized method on properties and structures of the co-polymers was studied. The emission intensity of the co-polymers at different RE3+ concentrations was tested. The results showed that the co-polymers of Eu-PSt and Eu-PMMA both had wide absorption peak at 200-400 nm and the strongest peak appeared at 235 nm. The fluorescent intensity of Eu3+ doped polystyrene co-polymer was stronger than that of Eu3+ doped PMMA copolymer. The characteristic emission of europium ions was observed in the co-polymers. The copolymer doped with rare earth elements showed the "sensitization effect" for the central ions. The bonded-type rare earth copolymer not only enhanced the energy transfer efficiency, but also improved the fluorescence intensity by iacreasmg the rigidity of main and side chain.     

Synthesis and Fluorescence Properties of Europium,Terbium Doped Zn^2＋, Cd^2＋, and Cr^3＋ Complexes

Europium and terbium complexes with strong fluorescence intensity and long fluorescence lifetime were prepared. By replacing half of the europium or terbium ion with M （M = Zn^2＋, Cd^2＋, and Cr^3＋） using the doped method, and then incorporating it with 18-crown-6 ether and terephthalic acid, six heteronuclear samples EuZnLL＇Cl3·3H2O（1）, EuCdLL2＇Cl3·5H2O（2）, EuCrLL＇Cl4· 4H2O（3）, TbZnLL＇Cl3·4H2O（4）, TbCdLL＇2Cl3·4H2O（5）, and TbCrLL＇2Cl4 ·4H2O（6） （L = terephthalic acid, L＇= 18-Crown-6 ether） were obtained. The elemental analysis, molar conductivities, rare earth complexometry, Fourier Transform Infrared Spectroscopy （FT-IR）, ultraviolet （UV）, TGA, fluorescence intensity, and fluorescence lifetime of the samples were measured. The results showed that there were good luminescence properties for heteronuclear complexes （1）, （2）, （4）, and （5）, which were even stronger than those of the homonuclear complexes Eu2LL＇2Cl4·4H2O and Tb2LL＇2Cl4 ·4H2O, but the luminescence properties of EuCrLL＇Cl4·4H2O, TbCrLL＇Cl4·4H2O were very weak. A possible luminescence mechanism was suggested by the organic-inorganic doped mechanism and the law of intramolecular energy transfer.     

铕铽混合掺杂聚合物的发光性能与微观形貌

将具有荧光性质的铕、铽以三异丙氧基稀土单一或混合的形式掺入甲基丙烯酸甲酯(MM A)或甲基丙烯酸甲酯与苯乙烯(S t)的混合单体中,形成凝胶,经原位聚合制备铕、铽单一或混合掺杂的PMM A或P(MM A-co-S t)聚合物,研究铕铽混合掺杂对材料发光性能的影响,并观察聚合物的微观形貌。结果表明:铕、铽混合掺杂PMM A或P(MM A-co-S t)中,主要呈现Eu3+的特征荧光,并使Eu3+发射强度显著提高;T b3+544nm处最强的发射峰消失了,而较弱的621nm处的发射峰却显著增强。ESEM显示了掺杂聚合物呈交联网络状的微观形貌。     

Preparation and properties of temperature sensitive paint based on Eu(DBM)3phen as probe molecule

Probe molecule Eu(DBM)3 phen is made up of europium oxide(Eu_2 O_3),dibenzoylmethane(DBM) and1,10-phenanthroline(phen). The temperature sensitive paint(TSP) was compounded by the polymerization of the probe molecule, methyl methacrylate(MMA) and the initiator of benzoyl peroxide(BPO).The structure, morphology, luminescence property of probe molecule and the temperature quenching property of the temperature sensitive paint(TSP) were characterized by infrared spectrometer, UV-vis spectrometer, scanning electron microscopy and fluorescence spectrometer respectively. The infrared spectrum and UV-vis spectra show that Eu and DBM form six membered rings, and Eu-O coordinate bonds form. The nanocrystals are in sphere-like morphology with an average size of approximately100 nm. Fluorescence spectra present that the performance of temperature quenching is excellent,what's more, TSP sample has different temperature sensitivity in various temperature scope. Particularly,under excitation of 286 nm, TSP has a highest temperature sensitivity between 50 and 60 ℃, and the strongest fluorescence emission reaches a peak(615 nm). It indicated that probe molecule(Eu(DBM)_3 phen) has strong luminescent intensity and the temperature quenching properties of Eu(DBM)_3 phen/PMMA is good.     

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 β). 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 and Characterization of Rare Earth Complexes

Rare earth (Eu³⁺) single nuclear chelated with α-methacrylic acid and 1, 10-phenanthroline, as well as the heteronuclear chelated of Eu³⁺ and La³⁺ ions, were synthesized. The composition and structure of the rare earth complexes were confirmed by IR, SEM and XRD. The thermal analysis indicated that the heat-stability was improved. Moreover, the fluorescence spectra proved that the complexes had good fluorescence property. The results showed that it was convenient to synthesize series of europium chelate. The complexes exhibited characteristic fluorescence of europium. ion. The sensitization of La³⁺ could enhance the fluorescence emission intensity of Eu³⁺ ion.     

Solvent induced shape change in CePO4:Dy3+ nanophosphors and effect of metal ions:A photoluminescence study

The influence of different solvents and metal ions (Li+, Ba2+, Bi3+) on the crystallization behaviour, morphology and enhancement in photoluminescence intensity of Dy3+ doped CePO4 were investigated. Highly crystalline luminescent nanophosphors of CePO4:Dy3+ re-dispersible in polar solvents were successfully prepared via a simple polyol route at 140 ℃. As-prepared Dy3+ doped CePO4 nanophos-phors prepared in EG and DMF appeared to have crystalline monoclinic phase but exhibited hexagonal phase when prepared in water and water mixed solvents. The hexagonal phase transformed to monoclinic phase after heating at 900 ℃. TEM study revealed different shapes of the synthesized nanophosphors with change of solvents. The luminescence intensity of 4F9/2→6H15/2 at 478 nm (blue) was found to be more prominent than 4F9/2→6H13/2 at 572 nm (yellow). The introduction of metal ions (Li+, Ba2+ and Bi3+) in CePO4:Dy3+ led to considerable lumi-nescent enhancement. The nanophosphors were subsequently incorporated in polymer films of PVA which showed the characteristic emissions of Dy3+. It also served as an effective method to improve the performance of polymer materials and brought about novel properties in them.     

Novel luminescent europium-centered hybrid material covalently grafted with organically modified titania via 2-substituted imidazophenanthroline for fluorescence sensing

By employing a rational approach,we prepared a novel kind of luminescent europium-centered hybrid material named Eu(tta)_3NCP-TiO_2.The resulting material was characterized by FT-IR spectra,SEM,X-ray diffraction,thermogravimetric analysis,and photoluminescence spectra.The hybrid material features the combined advantages of the europium complex and the titania host,exhibiting not only good thermostability,but also long luminescence lifetime.Owing to the excellent luminescence of this material,the application in detecting organic small molecule solvents and metal ions was explored systematically.Significantly,Eu(tta)_3 NCP-TiO_2 exhibits superior detection for nitrobenzene molecule and Cu~(2+) ion in DMF(N,N-dimethylformamide) medium.Furthermore,the limit of detection(LOD) of Eu(tta)_3 NCP-TiO_2 for nitrobenzene and Cu~(2+) ion can be counted as 5.593× 10~(-5) and 9.566 ×10~(-5) mol/L,respectively.The results demonstrate that Eu(tta)_3 NCP-TiO_2 can serve as an efficient fluorescence probe for the detection of sensing of nitrobenzene and Cu~(2+) ion.     

Study on Copolymer of PMMA with Eu Complex

The europium complex, Eu3 -1,10-phenanthroline (Phen) -acrylic acid (AA) was prepared and its structural formula is Eu(Phen) (AA)3. The high luminescence rare earth polymer materials were obtained by the copolymerization of europium complex with methyl methacrylate using AIBN as an initiator. The copolymer structure and properties were characterized by FT-IR, UV-Vis, RF spectra and thermogravimetric analysis (TG). Results indicate that block copolymer is synthesized. Fluorescent property shows that Eu copolymer emits rare earth fluorescence and the emission intensity increases with the rise in Eu content and reaches a maximum value.     

Fluorescence Properties of Eu3+/Gd3+/Citric Acid Mixed Complexes Doping in Silicon Rubber Matrix

Series of doped rare earth complexes-EuxGd(1-x)(CA)3·nH2O (CA=citric acid) were synthesized. Some characterizations were taken for these complexes. The experimental results shows that the doped rare earth complexes have the best fluorescence property when the ratio of Eu and Gd is from 0.7 to 0.3. Silicon rubber-based composites were prepared by mechanical blending the EuxGd(1-x)(CA)3·nH2O and silicon rubber. Then, the fluorescent property of the composites was studied. It is found that the fluorescence intensity of the composites increase linearly with the contents of the rare earth complexes increasing.     

Synthesis, characterization and fluorescence of N,N'-BIS (6-metyl-2-pyridine-carboxylamide-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.     

Structure,Upconversion and Fluorescence Properties of Er3+-Doped TeO2-TiO2-La2O3 Tellurite Glass

Tellurite glasses were generally applied in rare earth optical materials due to their excellent physical and chemical properties. In this study, novel tellurite glasses composed of TeO₂-TiO₂-La₂O₃ were prepared by conventional melting-quenching method. Some basic physical parameters such as density, refractive indices, transition temperature and crystalline temperature were measured. The structure was analyzed by Raman spectra. The absorption, upconversion and fluorescence spectra were measured by UV-Vis-NIR spectrophotometer and spectrofluorimeter. Under 980 nm laser excitation, upconversion luminescence centered at 531, 545 and 657 nm corresponding to the transition ⁴H_11/2→⁴I_15/2, ⁴S_3/2→⁴I_15/2 and ⁴F_9/2→⁴I_15/2 respectively, were observed. The effects of TiO₂ concentration on structure and upconversion luminescence intensity were discussed. The result indicated that the upconversion intensity increased as the phonon concentration decreased. The fluorescence properties of Er³⁺ doped glass were also studied. The dominant peak centered at 1531 nm and full width at half maximum (FWHM) was 64 nm. The Er³⁺ stimulated emission cross-section was calculated on the basis of McCumber theory. The possible mechanism of upconvesion and fluorescence were proposed.     

铕-噻吩甲酰三氟丙酮-活性配体三元配合物的合成及发光性能研究

以噻吩甲酰三氟丙酮为第一配体,顺丁烯二酸酐、十一烯酸、油酸、丙烯腈为活性第二配体,合成了四种新的反应型三元铕配合物。通过元素分析,EDTA配位滴定分析,红外、紫外、荧光光谱分析,对标题配合物的组成、结构进行了表征,并研究了它们的发光性能,结果表明,四种新的反应型三元配合物具有良好的发光性能,且配合物中引入了能与其它单体共聚的活性第二配体,为合成具有优异发光性能的键合型稀土高分子功能材料提供了一条新的途径。     

Synthesis and spectroscopic properties of rare earth picrate complexes with a new dinaphthalenelamide

The new ligand N-benzyl-2-{2’-[(benzyl-ethyl-carbamoyl)-methoxy]-dinaphthalene-2-yloxy}-N-ethyl-acetamide(L) and its complexes of rare earth picrates were synthesized.The complexes were characterized by elemental analysis,IR,UV-vis spectra and conductivity measurements.The fluorescence properties of the europium complex in solid state and CHCl3,ethyl acetone,acetonitrile and DMF were investigated.Under the excitation,the europium complex exhibited characteristic emissions of europium.The lowest triplet state energy level of the ligand indicated that the triplet state energy level of the ligand matched better to the resonance level of Eu(Ⅲ) than Tb(Ⅲ) ion.