Synthesis,Characterization,and Luminescence Properties of a Multi-benzoic Acid Rare Earth Complex Applied to Fluorescence Nanometer and Micrometer Fiber

The design and synthesis of a novel multi-benzoic acid ligand and the luminescence properties of the rare earth complex with the ligand and Eu3 +were focused on. The composition and structure of ligand and complex were characterized by Fourier transform infrared( FT-IR) spectroscopy,1H nuclear magnetic resonance(1H NMR) techniques, and element analysis. The luminescent properties,heat resistant performance,morphology and distribution in fibers of the complex were also measured. The fluorescent spectra indicate that as-synthesized complex owns excellent luminescent properties. The maximum relative fluorescence intensity of the complex is more than 7 000. The thermo-gravimetric analysis( TGA) results confirm that the initial degradation temperature of as-synthesized complex is at 413 ℃. Transmission electron microscope( TEM) and field-emission scanning electron microscope( FESEM) photos show that the particle size of assynthesized complex is 50-60 nm,and can be uniformly distributed in fiber. Based on these results, it can be concluded that the synthesized complex has excellent luminescent properties, good thermal stability,and extensively application prospect.

Crystal Structure and Fluorescent Study of a Binuclear Europium(Ⅲ) Complex

A novel binuclear Eu（Ⅲ） complex [Eu2（dpa dioxide）2（NO3）4（bpdioxide）-（EtOH）] （dpa dioxide = di-2-pyridylamine N,N＇-dioxide, bpdioxide = 2,2＇-bipyridine N,N＇-dioxide） has been synthesized and it exhibits strong and sharp fluorescent emission at 614 nm under UV radiation of 245 nm at room temperature. X-ray structural determination indicates two independent Eu（Ⅲ） ions in the structure with different EuO8N and EuOgN environments. The compound crystallizes in the triclinic system, space group P1, with a = 10.8089（7）, b = 11.4670（8）, c = 17.1440（12） A, α = 92.834（2）, β = 93.854（3）, γ = 95.433（2）°, Z = 2, Dc = 1.876 g/cm3, V= 2107.3（2） A3, F（000） = 1168.0, the final R = 0.032 and wR = 0.086 for 6331 observed reflections with I 〉 2σ（I）.

Progresses in electroluminescence based on europium(Ⅲ) complexes

The research on electroluminescence based on europium（III） complexes has come to an important phase. This article reviewed the progresses in photoluminescence and electrohiminescence of Eu（III） complexes in recent years from the views of the design of Eu（III） complexes and optimization of device structures, and discussed some important factors influencing electroluminescence performance. The problems existing in the practical application such as the volatility and thermal stability of Eu（III） complexes in this area were discussed, and the possible corresponding solutions were briefly prospected.

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 Tb0.5 RE0.5(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 of 1-(2-Hydroxyphenyl)-3-Phenyl-1,3-Propanedione and Luminescence Properties of Its Europium Complexes

Using 2＇-Hydroxyacetophenone and as the raw material, 1-（ 2-Hydroxyphenyl ）-3-Phenyl-1, 3- Propanedione （HPPPD） was synthesized by esterification reaction and Fries rearrangement reaction. And the complexes of HPPPD with europium were also synthesized. The compounds were characterized by IR, thermo-gravimetric analysis and ^1H-NMR. The effects of phenolic hydroxyl on the luminescence properties of complexes were studied. The results show that the complexes emit strong red fluorescence and the fluorescence intensity of the ternary complex is better than that of the duality. But the complexes of HPPPD with Sm（ Ⅲ ）, Tb （ Ⅲ ）, Dy （ Ⅲ ） emit weak fluorescence. The phenomenon was interpreted by electron-effect and energy-matching mechanism. Energy transfer mechanism of the luminescence in the complex was discussed.

Synthesis,crystal structure and fluorescence of a new europium complex with 2-bromobenzoate and 2,2'-bipyridine

A new complex of {[Eu2(2-BrBA)6(2,2’-bpy)2]2·CH3CH2OH·H2O} (2-BrBA=2-bromobenzoate; 2,2’-bpy=2,2’-bipyridine) was prepared by solvent method and characterized with X-ray single-crystal diffraction, IR spectroscopy, UV spectroscopy, and fluorescence spectroscopy. The complex crystallized in triclinic crystal system, Pī space group, with a=1.17196(4) nm, b=2.36142(9) nm, c=2.59151(9) nm, α=113.266(2)°, β=101.100(2)°, and γ=94.400(2)°. Two independent dinuclear molecules were contained in the asymmetric unit. The two molecules were similar to each other. Each Eu(Ⅲ) ion was nine-coordinated with seven oxygen atoms from five 2-BrBA ligands and two nitrogen atoms from 2,2’-bpy molecule. The carboxylate groups acted as bidentate-chelating, bidentate-bridging and chelating-bridging coordination modes. The complex adopted a distorted monocapped square-antiprism coordination geometry. Five peaks at 579, 591, 613, 652, and 697 nm appeared in the fluorescence spectrum, corresponding to 5D0→7F0, 5D0→7F1, 5D0→7F2, 5D0→7F3, and 5D0→7F4 transition emissions of the Eu(Ⅲ) ion, respectively.

Synthesis and photoluminescence of a dendritic europium complex with carbazole moieties

A novel dendritic europium complex containing grafted carbazole units as functional peripheries was synthesized and characterized. The Foerster energy transfer from the peripheries of carbazole units to β-diketonate as well as from the hgands to the central Eu（Ⅲ） ions in the complex was demonstrated. Under the excitation of carbazole units and β-diketonate, characteristic red emission peaks at 612 nm with four shoulders due to the Eu（Ⅲ） ion transition of 5^D0→7^FJ （J=0-4） were observed for the complex.

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.

Structure and Fluorescence Emission of Hetero-Nuclear Complexes of Europium-Lanthanum Nitrates with N,N′-Substituted Adipamide

A europium lanthanum hetero nuclear complex with new ligand N, N′ dimethyl N, N′ diphenyladipamide (MPAA) was prepared. The one dimensional chain structure of [La 0.5 Eu 0.5 (MPAA) 2(NO 3) 3] was determined crystallographicaly. The europium ion and lanthanum ion statistically lie at the position of the metal ion with M=1/2(La+Eu). Each Ln 3+ ion is nine coordinated including three bidentate nitrates, three carboxyl groups from three MPAA molecules, in which two MPAA are act as bridge ligand. The intensity of fluorescence of La 3+ Eu 3+ heteronuclear complex A was obviously higher than that of pure Eu 3+ complex B both in solution and in solid state.

Synthesis and Properties of Ternary Europium Complexes with Aromatic Carboxylic Acid and Nitrogen-Containing Heterocyclic Ligand

Seven ternary Eu （m） complexes were synthesized with aromatic carboxylic acid （benzoic acid, phenylacetic acid, phenylpropionic acid and cinnamic acid） as the first ligand and 1,10-phenanthro- line or 2,2＇-dipyridyl as the second ligand. The ternary Eu（ Ⅲ ） complexes were characterized by elemental analysis, IR and TG-DTG methods. In these complexes, the Eu （Ⅲ） ions are bonded to the oxygen atoms of carboxylate and the nitrogen atoms of neutral ligands. Four complexes whose second ligand is 1,10- phenanthrolin have fine thermal stability. Excitation and luminescence spectra of the tide complexes reveal that the fluorescence of the complexes in which 1,10- phenanthrolin as the second ligand are more intensive than those complexes in which 2, 2＇-dipyridyl as the second ligand. The order of the strongest emission peak of seven ternary complexes is： Eu（β-PPA）3phen 〉 Eu（BA）3phen 〉 Eu（PLA）3phen 〉 Eu（BA）3bipy 〉 Eu （ PEA）3bipy 〉 Eu （ CA ）3phen · H2O 〉 Eu （ CA ）3bipy （BA ： benzoic ; PEA ： phenylacetic ; β-PPA ：

Synthesis and Fluorescent Property of Europium Ternary Complex-MMA Copolymer

Under the mild condition a new ternary rare earth complex Eu （ DBM ）2MA · 2H2O [ DBM： C6H5COCHCOC6H5; MA： CH2C（CH3）COO^- ] was synthesized by the reaction of EuCl3 with dibenzoylmethane and methacrylate in alcohol. A new bonded copolymer Eu（DBM）2MA-MMA was prepared by copolymerization of the Eu（DBM）2MA·2H2O complex with methyl methacrylate（MMA） monomer using AIBN as an initiator. The composition, structure and fluorescence properties of the complex and copolymer were characterized by means of elemental analysis, complex titration, IR, UV-VIS and fluorescent spectra. The thermal stability, glass temperature and average molecular weight of the copolymer Eu（DBM）2MA-MMA were determined by TG-DTA, DSC and GPC, respectively. The research results show that both of the ternary rare earth complex and the copolymer can emit strong Eu（Ⅲ） fluorescence at 613 nm.

Synthesis, Structure and Photoluminescent Properties of A Novel Oxadiazole-Functionalized Europium(Ⅲ) Complex

A new oxadiazole-functionalized ligand, 2-benzamide-5-phenyl-[ 1,3,4 ] oxadiazole （HL1） was synthesized. With it as the first ligand, 2-Phenyl-imidazo[4,5-f] 1, 10-phenanthroline （L2） as the second ligand, a novel europium complex [Eu（L1）3L2] was prepared and characterized by X-ray structure analysis and photoluminescent spectrum. The complex crystallizes in triclinic with space group of Pi. The crystal data are as follows： a = 1.4892（3） nm, b = 1.6639 （3） nm, c=1.7258（4） nm, α =9.290（3） nm, β=11.014（3） nm, γ=11.554（3） nm, V=3520.7（12） nm^3, Z= 2, M = 1244, Dc = 1.292 g·cm^-3, μ = 1.381 mm^-1 and F（000） = 1389. The final R and wR values are 0. 0680 and 0. 1557 for 6607 [ I 〉 2σ （I）] unique reflections. In the complex, each Eu（ Ⅲ ） ion is eight-coordinated by three carbonyl oxygen atoms and three oxadiazole nitrogen atoms from L1, two nitrogen atoms from the L2, forming a distorted square antiprism coordination geometry. The complex shows intense red emission typical of Eu^3＋ ion under UV excitation, both ligands L1 and L2 exhibit strong antenna effects.

Synthesis and Photoluminescence of Three Europium (Ⅲ) Ternary Complexes with New Secondary Ligands of Different Structure

Three new 1,10-phenanthroline derivatives, dipyrido (3,2-f: 2,3-h) quinoxaline (DPQN), imidazo (5,6-f)-(1,10)-phenanthroline (IP) and 3-phenyl-imidazo (5,6-f)-(1,10)-phenanthroline (PIP) were designed and synthesized as a secondary ligand to coordinate with europium (Ⅲ) ion while dibenzoylmethane (DBM) was used as the first ligand. The compositions of the ligands and the europium (Ⅲ) ternary complexes were confirmed by elementary analysis, IR and (()~1H-NMR) spectroscopy. The UV-visible absorption spectra, thermal stability, photoluminescence spectra, quantum yield and fluorescence life time of the Eu(Ⅲ) complexes were investigated. The effect of the structure of the secondary ligand on the photoluminescence of the complexes was discussed. The results show that the synthesized Eu(Ⅲ) complexes are good red-emitiing materials for potential application in fabrication of organic electroluminescence devices.

Bright Red Luminescence from Novel Europium Complex Sensitized by Dibenzamide

A novel europium complex, bi(dibenzamide) benzoate europium(Ⅲ) (Eu-DBA-B), was synthesized. The composition and photoluminescence properties of Eu-DBA-B were investigated. The results show that the europium complex is an electroneutral complex, and it emits very strong red luminescence from (()~5D_1→()~7F_j) (j=0, 1, 2, 3, 4) transitions.

Synthesis and Fluorescence of Novel Conjugated Europium Complex

A novel organic ligand, 6 (ortho methyl anilino carbonyl) 2 pyridine carboxylic acid (H o MAP), and the corresponding europium complex, tris(6 (ortho methyl anilino carbonyl) 2 pyridine carboxylato) europium (Eu o MAP) were designed and synthesized. The results show that solid Eu o MAP is a conjugated complex, emitting strong red fluorescence dominantly due to a ligand sensitizd luminescence mechanism. The lifetimes of 5D 0 of Eu 3+ in the complex were examined using time-resolved spectroscopic analysis, and the lifetime values were (1.50±0.01) ms for solid Eu(o MAP) 3 and (1.10±0.01) ms for 1.0×10 -5 mol·L -1 Eu(o MAP) 3 ethanol solution, respectively. Thermogravimetric analysis shows that the europium complex has good thermal stability.

Hydrothermal synthesis, crystal structure and luminescence of a europium complex with phenylmalonic acid and 1, 10-phenanthroline

A new complex Eu2（PA）6（phen）2 was prepared with hydrothermal reaction using EuCl3.6H2O, phenylmalonic acid （H2phma）, and 1, 10-phenanthroline （phen）, where PA was the decarboxylated product of HEphma, phenylacetate. The crystal structure of the title complex was determined with the X-ray diffraction. The title complex was a binuclear molecule with an inversion center. Each Eu^3＋ ion was nine-coordinated with two nitrogen atoms from one phen molecule and seven oxygen atoms from five PA ligands. The carboxylic groups were bonded to the Eu^3＋ ion in three modes, the chelating bidentate, the bridging bidentate, and the bridging-chelating tridentate. The complex emits intense red fluorescence under ultraviolet light. The luminescence peaks correspond to the characteristic emission 5D0→7FJ （J=0-4） transitions of the Eu^3＋ ion.

Synthesis and Luminescence of Complexes Eu_x Y_(1-x)(phen)L_3

A series of binuclear complexes with different molar ratio of europium to yttrium with cinnamic acid and o phenanthroline were synthesized in anhydrous alcohol. Elemental analysis shows that the composition of the complexes are Eu x Y 1- x (phen)L 3 (L: C 6H 5CH=CHCOO, x =1.0, 0.7, 0.5, 0.3 and 0.1). The IR absorption spectra indicate that cinnamate is coordinated to the rare earth ions and chemical bonds are formed between rare earth ions and nitrogen atoms of o phenanthroline. Fluorescent spectra show that the emission of Eu 3+ ion can be greatly enhanced if some of europium ions in the complexes are substituted by yttrium ions.

Crystal Structure and Luminescence of 1,10-Phenanthroline-tris(4-methoxybenzoato)Europium

1,10 Phenanthroline tris(4 methoxybenzoate)europium, Eu( p MOBA) 3phen(where p MOBA= p methoxybenzoate and phen=1,10 phenanthroline) has been obtained in the ethanol solution. The crystal consists of binuclear molecules of the title compound. In the binuclear molecule each Eu 3+ ion is coordinated not only by four oxygen atoms from the bridging carboxylates, but also by two oxygen atoms of a bidentate carboxyl group and two nitrogen atoms of a phen chelating ligand, giving coordination number of eight. Eu O distances range from 0 2336(3) to 0 2483(3) nm. The average Eu N distance is 0 2624(4) nm. Luminescence data indicate that one Eu 3+ ion site is in low symmetry in the complex.

Photophysical Property of Ternary Complex Eu(DPHA)_3·Phen·2H_2O

One ternary complex of europium with the plant growth regulator HDPHA (2-Hydroxydiphenyl acetic acid) and Phen (1,10-Phenanthroline), Eu(DPHA) 3·Phen·2H 2O, was synthesized and characterized by the elemental analysis and DTA-TG measurement. The photophysical property of the complex was investigated by means of IR spectra, Raman spectrum and laser-exited, high-resolved excitation and emission spectra as well as time-resolved luminescence spectra. The luminescence spectra reveal four Eu 3+ sites with energy difference within 25 cm -1 and local symmetries of C 1 or C 2 or C s in the complex. The energy transfer among the Eu 3+ sites is observed. The 7F J sublevel splitting of the Eu 3+ ion is discussed.

Synthesis and Characterization of Eu_4(PMA)_3(phen)_(0.75)·7H_2O Ternary Luminescent Complex

Eu(Ⅲ)-Pyromellitic acid[PMA]-1, 10-phenanthroline (phen) ternary luminescent complex was prepared in ethanol and water mixed solvent. The elemental analysis, inductively coupled plasma-atomic emission spectroscopy (ICP-AES) fourier-transform infrared spectroscopy (FT-IR) indicates that its chemical constitution is Eu4( PMA)3( phen)0.75·7H2O. TG-DTA curves indicated that the complex is heat stable at the temperature of 430℃. The XRD patterns showed that the complex is a new crystal different from the two ligands' structures. SEM image indicates that the complex is in block shape and disperses well. Photoluminescence (PL) analysis indicates that the complex emits Eu3+ characteristic luminescence under ultraviolet excitation.