Fluorescence enhancement of Tb(Ⅲ) complex with a new β-diketone ligand by 1,10-phenanthroline

A novel β-diketone, 1-(3,4,5-trisbenzyloxy)benzoyl-5-benzoyl acetylacetone (TBAA), and its corresponding binary Tb(Ⅲ) complex Tb(TBAA)3·2H2O and ternary complex Tb(TBAA)3Phen with 1,10-phenanthroline (Phen) were prepared. The ligand was characterized based on elemental analysis, FT-IR, and 1H NMR. The complexes were characterized with elemental analysis, FT-IR and thermogravimetry and derivative thermogravimetry (TG-DTG). Photoluminescence measurements indicated that the energy absorbed by the organic ligan...     

Synthesis and luminescent properties of novel pyrazolone rare earth complexes

A novel pyrazolone pyridine-containing ligand,2,6-bis(1-phenyl-4-ethoxycarbonyl-5-pyrazolone-3-yl)pyridine (H2L) was de-signed and synthesized from pyridine-2,6-dicarboxylic acid (1),and its Eu(III) and Tb(III) complexes were prepared.The ligand and com-plexes were characterized in detail based on FT-IR spectra,1H NMR,elemental analysis and thermal analysis,and the formula of Ln2L3·4H2O (Ln=Eu or Tb) of rare earth complexes was confirmed.The UV-vis absorption spectra and photoluminescence properties of the complexes were investigated,which showed that the Eu(III) and Tb(III) ions could be sensitized efficiently by the ligand (H2L) and emit the photolumi-nescence with high intensity,narrow half-peak width,and monochromic light.The results indicated that the complexes showed potential as excellent luminescent materials.     

Synthesis,crystal structures and characterization of a pair of Tb~Ⅲ-based enantiomers

A pair of novel TbIII-based enantiomers,[Tb(dbm)3·LSS] (1) and [Tb(dbm)3·LRR] (2) (where LSS=(+)-4,5-pinene bipyridine,LRR= (–)-4,5-pinene bipyridine,dbm=dibenzoylmethanate),were synthesized and characterized based on single crystal X-ray diffraction,elemental analysis,FT-IR,TG and CD spectra.X-ray diffraction analysis showed that both the complexes crystallized in monoclinic crystal system with P21 chiral space group.The TbIII ion was eight-coordinated by six O atoms of three dbm ligands and two N atoms fr...     

Synthesis,characteristic and intramolecular energy transfer mechanism of reactive terbium complex in white light emitting diode

A reactive Tb(III) complex with 2-aminobenzoic acid(2-ABAH) and acrylonitrile(AN) as ligands was synthesized.The structure of the complex was characterized by elemental analysis and Fourier transform infrared spectrometry(FT-IR).The results indicated that the ligands were coordinated with Tb(III) ion.Thermal gravity-derivative thermogravimetric(TG-DTG) analysis indicated that the complex kept stable up to 198 oC.Luminescence properties were investigated by UV-vis absorption spectra and fluorescence spectra.The results suggested that being excited at 361 nm,the complex exhibited characteristic emission of Tb(III) ion,revealing that the complex could be excited by 365 nm ultraviolet chip.The HOMO and LUMO,ΔE(HOMO-LUMO),molecular frontier orbital,and the singlet state and triplet energy state levels of the ligands were calculated at the B3LYP/6-31+G(d) level.The results indicated that intramolecular energy transfer mechanism followed Dexter exchange energy transfer theory.Both the calculation for excited state of ligand and energy transfer mechanism could provide the theoretical basis for the design of high luminescent materials of rare earth complexes with organic ligands.     

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.     

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.     

Synthesis and spectral characterization of lanthanide complexes with 1,2-diphenyl-4-butyl-3,5-pyrazolidinedione： Luminescent property of Tb（Ⅲ） complex

The complexes of rare earth elements with 1,2-diphenyl-4-butyl-3,5-Pyrazolidinedione (PBH, phenylbutazone) were synthesized and characterized by elemental analysis, molar conductance, IR, UV-Vis, EPR and magnetic moment measurements. Based on these studies the complexes were formulated as [Ln(PB)3(H2O)2]?nH2O, where Ln=Eu(III), Gd(III), Tb(III), Dy(III) and Er(III). From IR spectra, it was found that PBH acted as a bidentate mono-ionic ligand coordinating through two carbonyl oxygen of the pyrazolidinedione ring. The thermal analysis of all the complexes was carried out at a heating rate of 10 oC/min. The kinetic aspects of the complexes were evaluated. The nega-tive entropy value of the complexes indicated a more ordered state for the activated complexes. The photoluminescence property of Tb(III) complex was investigated. It showed all the characteristic emission peaks of Tb3+ with a life time of 0.98914 ms.     

Synthesis, characterization and properties of some rare earth complexes with 2,6-pyridine dicarboxylic acid and α-Picolinic acid

Five novel ternary complexes were synthesized by the rare earth with 2,6-pyridine dicarboxylic acid andα-picolinic acid.These complexes were characterized by elemental analysis,molar conductivity,FT-IR,UV-Vis,Raman,TG-DTA and XRD.The general formula of the complexes was[RE(DPA)(L α )(H2O)]·2H2O(RE=Pr 3+ ,Nd 3+ ,Sm 3+ ,Eu,Er 3+ ;DPA=2,6-pyridine dicarboxylic acid;L α =α-picolinic acid). The investigation of fluorescence properties of the Eu-complex showed that the Eu(III)ion could be sensitized efficiently by the ligand to some extent.The antibacterial activity test indicated that all the five complexes exhibited antibacterial ability against Escherichia coli and Staphylococcus aureus with broad antimicrobial spectrums.     

Preparation and Properties of Rare Earths with 6-Methyl-2-Picolinic Acid N-Oxide and 2,2'-Bipyridine-N,N'-Dioxide

A series of new ternary complexes of 6-methyl-2-picolinic acid N-oxide(HL) and 2,2'-bipyridine-N,N'-dioxide(bipyO2) with Ln3+(Ln=La, Sm, Eu, Gd, Tb, Dy, Yb) were synthesized and characterized. The composition of the ternary complexes is determined as {LnL3·bipyO2·H2O} (n-1)H2O (n=2.5～3.0). They are nonelectrolytes in ethanol. It is found that fluorescence intensities of the ternary complexes, LnL3·bipyO2·H2O, are weaker than those of binary complexes, LnL3·H2O. And it is also found that Tb3+ luminescence at 489.3 nm in TbL3·bipyO2·H2O is sensitized by bipyO2, and it is stronger than that at 543.8 nm, Which differs from TbL3·H2O.     

Syntheses,characterization, and luminescence of two lanthanide complexes [Ln2（acetate）6（HeO）4]·4H2O （Ln=Tb（1）, Sm（2））

Two dinuclear compounds [Ln2（acetate）6（H2O）4]-4H2O （Ln=Tb（1）, Sm（2）） were obtained by the hydrothermal reaction of Ln2O3 with malonic acid at 150 ℃. Both compounds were characterized by elemental analyses, infrared spectra, and single crystal X-ray diffraction. The results showed that complexes 1 and 2 were isomorphous and crystallize in triclinic space group P 1. The coordination geometry around Ln（Ⅲ） ions in the complexes 1 and 2 was a distorted tricapped trigonal prism with a nine coordination. In the crystal, the molecular organization was further stabilized by well-defined weak hydrogen bonding interactions between the neutral dinuclear molecular units that led to the formation of a three-dimensional network. The fluorescence properties of the two complexes 1 and 2 in organic solvents were also studied. The results show that the ligand acetate favored energy transfer to the emitting energy level of Tb（Ⅲ） in complex 1. Some factors that influence the fluorescent intensity were also discussed in the article.     

Synthesis and fluorescence properties of Eu（Ⅲ）, Tb（Ⅲ） and Sm（Ⅲ） with β-diketone and 2,2＇- bipyridine

Three new rare earth ternary complexes,RE(PPP)3bpy(RE=Sm 3+ ,Eu 3+ ,Tb 3+ ),were synthesized by the reaction of 1-phenyl-3-(p-phenylethynylphenyl)-1,3-propanedione(HPPP)and 2,2′-bipyridine(bpy)with rare earth chloride RECl3,respectively,in alcohol solution. The compositions were characterized by means of infrared(IR)spectra,chemical analysis,elemental analysis,and thermodynamic analysis.Luminescent properties of the three complexes were studied.At room temperature,under UV light excitation,the Sm 3+ ,Eu 3+ and Tb 3+ complexes exhibited characteristic emission of the central ions.The fluorescence spectra showed that the fluorescence emission intensity of Eu 3+ complex was the strongest.The narrow strongest emission band of Eu 3+ complex was considered to be a valuable material with bright red fluorescence.     

Fluorescence and Judd-Ofelt analysis of rare earth complexes with maleic anhydride and acrylic acid

Two kinds of Eu-complexes, Eu(TTA)2(Phen)(AA) and Eu(TTA)2(Phen)(MA) (HTTA=2-Thenoyltrifluoroacetone, Phen=1,10- phenanthroline, AA=acrylic acid, MA=Maleic anhydride), which combined the excellent fluorescence properties of Eu(TTA)2(Phen)(H2O) and the reactivity of acrylic acid and maleic anhydride with radicals, were synthesized. The two complexes were characterized by elemental analysis, infrared (IR) spectra, and X-ray photoelectron spectroscopy (XPS). Based on the data shown from the fluorescent spectra of the Eu-MA and Eu-AA complexes, the ?λ (λ=2 and 4) experimental intensity parameters were calculated. The results demonstrated that the ?2 intensity parameters for the two complexes were smaller than those for the Eu(TTA)2(Phen)(H2O) complex, indicating that a less symmetri- cal chemical environment existed in the complexes. It implied that the radiative efficiency of the 5D0 of these two complexes could be en- hanced by ligand of MA and AA, respectively. The luminescent lifetime of the Eu-AA (τ=7.26×10–4 s) or Eu-MA complex (τ=8.12×10–4 s) was higher than that of the Eu(TTA)2(Phen)(H2O) complex, which was attributed to the substitution of the water molecule (H2O) in Eu(TTA)2(Phen)(H2O) by the MA or AA ligand.     

Synthesis and photoluminescent properties of doped ternary Eu_(1-x)Ln_x(NPPD)_3·DPQ complexes

Rare earth (RE) ternary complexes of Eu0.5Ln0.5(NPPD)3·(DPQ) (HNPPD=1-(naphthalen-2-yl)-3-phenylpropane-1,3-dione; DPQ= dipyridobenzoquinone) and Eu1-xLax(NPPD)3·(DPQ) (Ln3+=La3+, Gd3+, Sm3+, Pr3+; x=0.0, 0.1, 0.3, 0.5, 0.7, 0.9) were synthesized by the reaction of RECl3·6H2O with HNPPD and DPQ in stoichiometry. The complexes were characterized with IR, elemental analysis, TGA-DSC and wide-angle X-ray diffraction. The UV-Vis absorption spectra and fluorescence properties of the complexes were also investigated. The experimental results showed that the luminescence efficiency of Eu3+ complexes was enhanced by doping some other lanthanide ions. Eu0.7La0.3(NPPD)3·(DPQ) showed the highest luminescence efficiency.     

Highly luminescent europium and terbium complexes based on succinimide and N-hydroxysuccinimide

The preparation of two highly luminescent europium(III) and terbium(III) complexes with succinimide(SI) and N-hydroxysuccinimide(NHSI) were reported,which were further investigated through elemental chemical analysis,thermal analysis,FT-IR,powder X-ray diffraction,SEM and fluorescence spectroscopy.Data collected through these analysis revealed the formation of the Eu(III) and Tb(III) complexes with the above mentioned ligands at a metal to ligand(M:L) molar ratio of 1:3.Interesting conclusions regarding the efficient sensitization through the coordination site of the lanthanide luminescent centers were retained from the photoluminescent spectra investigation.Strong luminescence emission was observed in case of Eu(III)-SI and Tb(III)-NHSI complexes while the corresponding Eu(III)-NHSI and Tb(III)-SI complexes exhibited no photo luminescent properties.Newly obtained luminescent lanthanide complexes may be of particular interest for various applications in optoelectronics.     

Synthesis, Characterization and Thermal Decomposition of Ln (Me2dtc)3(phen) (Ln=La, Pr, Nd, Sm)

Four solid complexes of Ln(Me2dtc)3(phen) (Ln=La, Pr, Nd, Sm) were synthesized in anhydrous ethanol by the reaction of lanthanide chloride low hydrate with the mixed ligand of sodium dimethyldithiocarbamate and 1, 10-phenanthroline·H2O (phen·H2O), and characterized by elemental analysis, IR spectroscopy, TG-DTG, and X-ray diffraction analysis. TG-DTG with X-ray powder diffraction showed that these compounds could decompose to lanthanide sulfides at relatively lower temperature, which indicated that the title complexes could be favorable precursors to prepare lanthanide sulfides.     

Synthesis and characterization of terbium（Ⅲ）-pyromellitic acid（H4L）-1,10-phenanthroline （phen） luminescent complex

The terbium(Ⅲ)-pyromellitic acid(H4L)-1,10-phenanthroline(phen) luminescent complex was synthesized using a co-precipitation method.The chemical composition of the synthesized complex was speculated to be Tb4L3(phen)0.075·10H2O by elemental analysis,inductively coupled plasma-atomic emission spectroscopy(ICP-AES),and Fourier-transform infrared spectroscopy(FT-IR).The X-ray diffraction analytic results indicated that the synthesized complex is a new crystalline complex,whose structure was different from those of other two ligands.The scanning electron microscopy analytic results showed that the product was of spherical crystals with good dispersion property,and the mean diameter of the spheres was about 1-2 μm.The TG-DTA result showed that the complex had good stability below 489 °C.PL spectra showed that the complex emitted characteristic green fluorescence of Tb(Ⅲ) ion under ultraviolet excitation.     

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, fluorescence and DNA-binding studies of europium（Ⅲ） pirates complexes with amide-based 2,3-dihydroxynaphthalene derivatives

Two ligands 2,2′-[2,3-naphthylenebis(oxy)]-bis(N-benzyl(acetamide))(L1) and 2,2′-[2,3-naphthylenebis (oxy)]-bis(N,N-diphenyl (acetamide))(L2) and their europium(Ⅲ) picrate complexes were synthesized. The complexes were characterized by elemental analysis, infra-red (IR), thermogravimetry and differential thermal analysis (TG-DTA) and molar conductivity. Fluorescent experiments showed that the resonance level of the Eu) matched better to the triplet state energy level of the ligand L2 than that of the ligand L1 and the fluorescence in-tensities of the complexes were reduced with the raising coordination ability of solvent. In addition, the interactions between the complexes and DNA were studied by means of spectrometry and cyclic voltammetry. The results suggested that the complexes could bind to DNA through intercalation and the complex 1 binded to DNA more strongly than the complex 2.     

Synthesis, structure and spectroscopic studies of europium complex with S（＋）-mandelic acid

The Eu3+ complexes with S(+) -mandelic acid were synthesized in the form of powders by mixing aqueous solutions of EuCl3,S(+) -mandelic acid and NaOH in different molar ratios.The powders were characterized by elemental analysis,X-ray powder diffraction(XRPD) method,Fourier transform infrared(FTIR) and Raman spectroscopy,UV-vis reflectance and luminescence spectra as well as lumi-nescence lifetime measurements.It was found that all studied powders of Eu3+ complexes with S(+) -mandelic acid were isostructural and crystalline and formed compounds with the formula Eu(Man) 3(H2O) 2.     

Thermochemical Properties of the Complexes RE(HSal)3·2H2O (RE=La, Ce, Pr, Nd, Sm)

Five solid rare earth salicylate complexes were synthesized by low hydrated lathanide chloride and salicylic acid. The complexes in this experiment were identified as the general formula RE(Hsal)3·2H2O(RE=La, Ce, Pr, Nd, Sm) by elemental analysis and EDTA volumetric analysis. IR spectra of the complexes show that carboxyl of salicylic acid coordinates to RE3 ions. Electrochemical behaviors of the complexes on the glass-carbon electrode were researched with cyclic voltammetry (CV). It is indicated that the electrochemical process of the complexes is a one-electron redox process and the electrochemical reversibility of complexes is less than that of the lanthanide chlorides. The constant-volume combustion energies of complexes, ΔcU, were determined with a precise rotating-bomb calorimeter at 298.15 K. Their standard molar enthalpies of combustion, ΔcHθm, and standard molar enthalpies of formation, ΔfHθm, were calculated.