Synthesis,characterization and luminescence properties of Eu(III) and Tb(III) complexes with novel pyrazole derivatives and 1,10-phenanthroline

Two novel pyrazole-derived ligands, 3-chloro-6-(3,5-dimethyl-1H-pyrazol-1-yl)picolinic acid (CDPA) and 3-chloro-6-(3,5-dimethyl-1H-pyrazol-1-yl)-N-phenylpicolinamide (CDPP) were prepared by 3,6-dichloropicolinic acid (DCPA). Their complexes with terbium(III) and europium(III) were synthesized. The complexes were characterized by elemental analysis, infrared spectra, ¹H NMR and TG–DTG. Furthermore, the above complexes using 1,10-phenanthroline as a secondary ligand were also synthesized and characterized. The luminescence properties of these complexes in solid state were investigated. The results suggested that Tb(III) complexes exhibit more efficient luminescence than Eu(III) complexes and the fluorescence of the complexes with 1,10-phenanthroline as a secondary ligand was prominently stronger than that of complexes without this ligand., and the three ligand (DCPA), (CDPP) and (CDPA) are excellent sensitizers to Eu(III) and Tb(III) ion.     

New Heteroaromatic Complexing Agents and Luminescence of Their Europium(III) and Terbium(III) Chelates

Twelve heteroaromatic complexing agents 9a–I were synthesized with the purpose to develop suitable labels for time-resolved luminescence-based bioaffinity assays. The relative luminescence yields, excitation maxima, and emission decay constants of their europium(III) and terbium(III) chelates were determined. According to these results, 2,2′,2″,2?-[(2,2′-bipyridine-6,6′-diyl)bis(methylenenitrilo)]tetrakis (acetic acid) ( 9e ) and 2,2′,2″,2?-[(2,2′:6′,2″-terpyridine-6,6″-diyl)bis(methylenenitrilo)] tetrakis(acetic acid) ( 91 ) are the most promising agents.     

Mössbauer study of mixed-ligand complexes of europium(III)

A series of europium(III) mixed complexes was prepared containing 1,10-phenanthroline or 2,2-bipyridine as neutral ligand and simple inorganic anions or benzoate and its derivatives as ionic ligands. The Mössbauer spectra of the products indicated that both types of ligands were directly coordinated to the central europium(III) atom. The Mössbauer isomer shift values reflected both electron shifting and steric effects of the substituents on the ligand. The quadrupole splitting values pointed to the similar symmetry of the electron shell of the europium in almost all complexes with analogous composition. The IR spectra provided evidence of the binding mode of the carboxylate groups in the complexes containing benzoate or its derivatives. The x-ray photoelectron spectra of the compounds demonstrated the effects of electrophilic and nucleophilic substituents on the electron binding energies in the europium, oxygen, and nitrogen orbitals.     

Luminescent Properties of Europium(III) Complexes with Quinaldic Acid and Sulfur–Containing Neutral Ligands

The luminescent heteroligand complexes of europium(III) with quinaldic acid and sulfur-containing neutral ligands Eu(Quin)3∙D∙3H2O (Quin–quinaldic acid, D–dimethyl sulfoxide or dihexyl sulfoxide) and Eu(Quin)3∙3H2O have been obtained. Their composition and structure have been determined. The thermal and spectral-luminescent properties of the heteroligand europium(III) complexes have been studied. The quinaldate ion has been found to coordinate to the europium(III) ion as a bidentate ligand. The Stark structure of 5D0–7Fj (j = 0, 1, 2) transitions in the low-temperature luminescence spectra of the europium(III) complexes has been analyzed     

Synthesis,structures, and magnetic and optical properties of a series of europium(III) and gadolinium(III) complexes with chelating nitronyl and imino nitroxide free radicals

This paper reports the synthesis, structures, and magnetic and optical properties of a series of gadolinium(III) (1a-4a) and europium(III) (1b-4b) complexes with nitronyl or imino nitroxide radicals. The crystal structures of compounds 1a and 1b consist of [Ln(III)(radical)(2)(NO(3))(3)] entities in which the gadolinium(III) (1a) or europium(III) ion (1b) is 10-coordinated to two nitronyl nitroxide radicals and three nitrato ligands. The crystal structures of compounds 2a-4a and 2b-4b consist of [Ln(III)(hfac)(3)(radical)] entities in which the gadolinium(III) (2a-4a) or europium(III) ion (2b-4b) is 8-coordinated to one nitronyl (2a and 2b) or one imino (3a, 4a and 3b, 4b) nitroxide radical and three hexafluoroacetylacetonato ligands. The gadolinium(III) complexes (1a-4a) are isostructural with their europium(III) analogues (1b-4b). The magnetic properties of the gadolinium complexes were studied. Along the series 1a-4a only compound 2a exhibits a ferromagnetic Gd(III)-radical coupling (J(Gd-rad) = +1.7 cm(-1)), while for the others this coupling is antiferromagnetic (1a: J(Gd-rad1) = -4.05 cm(-1) and J(Gd-rad2) = -0.80 cm(-1); 3a: J(Gd-rad) = -2.6 cm(-1); 4a: J(Gd-rad) = -1.9 cm(-1)). The first full luminescence spectra of lanthanide complexes with free radical ligands are reported between 650 and 1200 nm. The rich vibronic structure in luminescence and absorption spectra indicates that several excited states define the absorption spectra between 400 and 800 nm. Qualitative trends can be established between magnetic ground state properties and the energies and fine structure of the title compounds.     

Simultaneous spectrophotometric determination of atrazine and cyanazine by chemometric methods

Three novel ligands containing pyridine-2,6-dicarboxylic acid unit, trans-4 -(4'-methoxystyryl) pyridine-2,6-dicarboxylic acid, trans-4-(4'-(dimethylamino)styryl)pyridine-2,6-dicarboxylic acid, and trans-4-(4'-(diphenylamino)styryl)pyridine-2,6-dicarboxylic acid were synthesized and their complexes with Eu(III), Tb(III) ions were successfully prepared. The ligands and the corresponding metal complexes were characterized by means of MS, elemental analysis, IR, (1)H NMR and TG-DTA. The luminescence spectra of Eu(III) and Tb(III) complexes in solid state were studied. The strong luminescence emitting peaks at 615 nm for Eu(III) and 545 nm for Tb(III) can be observed. The applications in cell imaging of the europium and terbium complexes were investigated.     

Comparative spectroscopic and electrochemical properties of bis(octakis(dodecylthio)naphthalocyaninato)europium(III) and bis(tetra-tert-butylnaphthalocyaninato)europium(III) complexes

Bis(substituted-2,3-naphthalocyaninato)europium(III) complexes: bis(octakis(dodecylthio)-2,3-naphthalocyaninato)europium(III) (Eu[2,3-Nc(SC12H25)8]2, 1) and bis(tetra-tert-butyl-2,3- naphthalocyaninato)europium(III) (Eu[2,3-Nc(t-Bu)4]2, 2) have been synthesized by cyclic tetramerization of naphthalonitriles with Eu(acac)3.H2O in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in refluxing n-octanol. These compounds were characterized by UV-visible, magnetic circular dichroism (MCD), near-IR, IR, EPR, and mass spectroscopies. The absorption and MCD spectra of 1 showed splitting of the Q band, with peaks at 700 and 784 nm, red shifted from the Q band of 2 at 763 nm. The absorption and MCD spectral band deconvolution calculations of complex 1 gave two A terms in the Q-band region. The A terms are assigned to 2A2-->2E1 transitions. Cyclic voltammograms of 1 and 2 showed reversible oxidation couples at E1/2 = -0.28 V (for 2) and -0.25 V (for 1) vs ferrocenium/ferrocene (Fc+/Fc). The second oxidation exhibited a complicated behavior for both complexes. The reduction couples for 2 were observed at E1/2 = -0.61, -1.64, -1.97, and -2.42 V, and for 1 they were observed at E1/2 = -0.62, -1.60, -1.86, and -2.27 V vs Fc+/Fc. Spectral changes observed on chemical oxidation and reduction of the complexes are presented, and the behaviors of 1 and 2 are compared.     

Polymethoxyphenyl-substituted [2-(5-chloro-2-hydroxy-4-methylphenyl)-2-phenylvinyl]phosphine oxides: Synthesis and complexation with Eu(TTA)3

New di- and trimethoxyphenyl-substituted phosphorus-containing ligands, (Z)-[2-(5-chloro-2-hydroxy-4-methylphenyl)-2-phenylvinyl]bis(3,4-di- and 3,4,5-trimethoxyphenyl)phosphine oxides, have been synthesized, and their adducts with europium(III) 2-thenoyltrifluoroacetonate have been obtained. High luminescence intensity of the synthesized complexes suggests prospects in using them for the design of various materials possessing unique photophysical properties.     

Synthesis and fluorescent properties of europium complexes with amide-type podand ligands of methyl salicylate

Amide-type podands derived from N,N′-(ethane-1,2-diyl)bis(2-hydroxybenzamide) and 2-chloro-N-phenylacetamide (substituted with methyl, methoxy, chlorine, nitrogen) were synthesized. Solid complexes of europium nitrate with podands were also synthesized and characterized by elemental analysis, ethylenediaminetetraacetic acid (EDTA) titrimetric analysis, thermal analysis, molar conductivity analysis, and infrared (IR) and ultraviolet–visible (UV–Vis) spectra analysis. The fluorescent properties of the europium(III) [Eu(III)] complexes in a solid state were also investigated. Under excitation of UV light, target Eu(III) complexes exhibited characteristic europium ion emissions. The influence of the substituent on the fluorescence intensity was discussed. Electrochemical properties were also investigated and discussed.     

Delayed lanthanide luminescence sensing of aromatic carboxylates using heptadentate triamide Tb(III) cyclen complexes: the recognition of salicylic acid in water

The coordinately unsaturated terbium complexes Tb.1 and Tb.2 possess two labile metal-bound water molecules that can be displaced upon metal chelation to aromatic carboxylic anions such as salicylic acid in water, which gives rise to large enhancements in the Tb(III) luminescence.     

Luminescent and triboluminescent properties of europium(III) complex with cinnamic acid

An intensely emitting crystalline europium(III) complex with cinnamic acid [Eu(Cin)₃] _n and exhibiting triboluminescent properties is synthesized. It is established that the measured photo- and triboluminescence spectra are identical for the above polymeric non-centrosymmetric complex and are determined by the characteristic f-f luminescence of the europium(III) ion.     

Studies on synthesis, infrared and fluorescence spectra of new europium (III) and terbium (III) complexes with an beta-diketonate-type ligand

A new beta-diketonate-type ligand, N-(2-amino-6-methyl-pyridinyl)ketoacetamide (L) and its complexes with europium (III) and terbium (III) were synthesized. The complexes were characterized by elemental analysis, infrared spectra and conductivity. The europium (III) and terbium (III)-ions were found to coordinate to the CO oxygen atoms and pyridine nitrogen atoms. The fluorescence properties of these complexes in solid, DMF and CH3OH were studied. The solvent factors influencing the fluorescent intensity are discussed.     

New luminescent europium(III) chelates for DNA labeling

The new europium(III) chelate [2,2',2',2'-[[4'-(aminobiphenyl-4-yl)-2,2':6',2'-terpyridine- 6,6'-diyl]bis(methylenenitrilo)]tetrakis(acetato)] europium(III) (ATBTA-Eu3+) and its 4,6-dichloro-1,3,5-triazinyl and succinimidyl derivatives (DTBTA and NHS-ATBTA, respectively) were synthesized and characterized. Both labeling complexes DTBTA-Eu3+ and NHS-ATBTA-Eu3+ are luminescent. Especially DTBTA-Eu3+ is strongly luminescent, with a luminescence quantum yield of 9.1%, molar extinction coefficient of 3.1 x 10(4) cm(-1) M(-1) (335 nm), and luminescence lifetime of 1.02 ms. The excitation and emission maximum wavelengths of DTBTA-Eu3+ are 335 and 616 nm, respectively. The complex is very stable in aqueous buffers, with a conditional formation constant log K(DTBTA-Eu) of 25.0 at pH 8, and can be conjugated to DNA and proteins. The chelates are also highly resistant to thermal decomposition, photodegradation, and ozone oxidation. These properties prove that DTBTA-Eu3+ is suitable as a luminescence label in DNA assays.     

Complexation of europium(III) by bis(dialkyltriazinyl)bipyridines in 1-octanol

The present work focuses on highly selective ligands for An(III)/Ln(III) separation: bis(triazinyl)bipyridines (BTBPs). By combining time-resolved laser-induced fluorescence spectroscopy, nanoelectrospray ionization mass spectrometry, vibronic sideband spectroscopy, and X-ray diffraction, we obtain a detailed picture of the structure and stoichiometry of the first coordination sphere of Eu(III)-BTBP complexes in an octanolic solution. The main focus is on the 1:2 complexes because extraction studies revealed that those are the species extracted into the organic phase. The investigations on europium(III) complexes of BTBP with different triazin alkylation revealed differences in the formed complexes due to the bulkiness of the ligands. Because of the vibronic sidebands in the fluorescence spectra, we were able to detect whether or not nitrate ligands are coordinated in the first coordination sphere of the Eu-BTBP complexes. In solution, less sterically demanding BTBP offers enough space for additional coordination of anions and/or solvent molecules to form 9-coordinated Eu-BTBP 1:2 complexes, while bulkier ligands tend to form 8-fold-coordinated structures. We also report the first crystal structure of a Ln-BTBP 1:2 complex and that of its 1:1 complex, both of which are 10-coordinated.     

Luminescent properties of europium(III) and terbium(III) complexes with para- and ortho-ethoxybenzoic acids

The luminescent properties of europium(III) and terbium(III) complexes with para- and ortho-ethoxybenzoic acids are studied. The excitation energies of the triplet states of ligands are determined, a hypothesis is made about the efficient luminescence of europium(III) and terbium(III) complexes, the geometry of the coordination polyhedron of a europium complex is established, and the luminescence quantum yields of the complexes in solution are determined.     

三种新的铕(III)三元配合物的合成及发光性质研究

合成了吡嗪 [2 ,3 f]并邻菲罗啉及其一系列衍生物 ,作为第二配体 ,并以二苯甲酰甲烷为第一配体 ,合成了 3种新的铕 (III)三元配合物 .通过元素分析、红外光谱、核磁共振光谱确定了它们的组成 ,研究了三种配合物的热稳定性、成膜性能和光致发光性能 (发光强度、荧光量子效率和寿命 ) ,并初步从理论上探讨含有不同基团的第二配体的结构对铕 (III)配合物发光的影响 ,结果表明 :这三种铕 (III)三元配合物均为优良的红色发光材料 ,而且在真空条件下均形成均衡的薄膜 ,这为以这三种铕 (III)配合物作为发光层材料制作有机电致发光器件提供了认识基础     

Europium(III) complexes containing organosilyldipyridine ligands grafted on silica nanoparticles

This work focuses on the grafting of transition metal complexes on silica surface nanoparticles. Nanoscale silica particles in aqueous sols are used as starting silicated materials. We have undertaken the synthesis of europium(III) complexes containing organosilyldipyridine ligands, (EtO)3Si(CH2)3NHCH2-bipy (1) and (EtO)(CH3)2Si(CH2) 3NHCH 2-bipy (2), in view of a direct grafting reaction on silica nanoparticles. Reaction of one molar equivalent of 1 and 2 with Eu(tmhd)3 (tmhd= 2,2,6,6-tetramethyl-3,5-heptanedionato), as precursor, leads to octacoordinated silylated europium(III) complexes [Eu(tmhd)3(1)] (3) and [Eu(tmhd)3(2)] (4) as white solids in 34-54% yields. Europium complexes were characterized by elemental analysis, mass spectrometry, FT-IR, UV, and luminescence spectroscopies. These new complexes are reacting in a 1:10 (v/v) water and ethanol mixture with silica nanoparticles colloidal sol. Elemental analysis and thermogravimetric data indicated grafting ratios of 0.41 and 0.26 mmol of europium(III) complexes per gram of silica. Functionalized silica nanoparticles were characterized by DRIFT spectroscopy and TEM microscopy. The first analysis shows that the chemical integrity of the complexes is retained on the silica surface together with the size and the monodispersity of the nanoscale particles. As expected for europium(III) complexes, luminescence is observed under UV irradiation. Emission and excitation spectra indicate that the metal coordination environment is not modified on the silica surface. Moreover, the sharpness of the luminescence bands and the strong antenna effect are maintained when complexes are covalently bonded to silica. New luminescent europium(III) complexes grafted on silica nanoparticles are therefore obtained from our approach.     

Enhancement of the luminescence efficiency of europium(III) tris(β-diketonato) complex in organic media by quaternary ammonium salts with anionic ligands

Benzyldimethyltetradecylammonium (BA14(+)) salts with anionic ligands (X(-)), such as bis(2-ethylhexyl)sulfosuccinate, bis(2-ethylhexyl)phosphate (BEHP(-)), and benzotriazole (BTA(-)) anions, were prepared. These salts were soluble in various organic solvents. The luminescence emission spectra of organic solutions of a red luminescent, tris(1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octadionato)europium(III) complex in the presence of the BA14X's were recorded. The emission intensity of the Eu(III) complex was increased remarkably by the addition of BA14X (X(-) = BEHP(-) and BTA(-)). This effect can be attributed to the formation of 1:1 X(-)-adducts of the Eu(III) complex, in which the asymmetry of the ligand field is increased so as to enhance the emission efficiency of the (5)D(0)→(5)F(2) transition. The enhancement effect by BA14X was higher than that of charge-neutral ligands, such as tri-n-octylphosphine oxide and 1,10-phenanthroline, which have been used as second ligands to enhance the emission efficiency of tris(β-diketonato)europium(III) complexes.     

Europium(III) interaction with a polyaza-aromatic extractant studied by time-resolved laser-induced luminescence: a thermodynamical approach

The 2,6-bis(5,6-dialkyl-1,2,4-triazin-3-yl)pyridines (DATPs) belong to a new family of extracting agents recently developed in the framework of nuclear fuel reprocessing. These molecules exhibit exceptional properties to separate actinides(III) from lanthanides(III) in nitric acid solutions. In a previous work, the use of electrospray ionization mass spectrometry (ESI-MS) provided data such as stoichiometries and conditional stability constants of various DATP complexes with europium and evidenced the unusual capability of DiPTP [bis(di-iso-propyltriazinyl)pyridine] ligand to form 1:3 complexes in nitric acid solution. This latter result has then been further investigated by considering DiPTP complexation features with the complete lanthanide family. Moreover, a complementary study of equilibria in solution with a non intrusive technique such as time-resolved laser-induced luminescence (TRLIL) seemed quite promising to determine thermochemical data such as enthalpy and entropy variations associated with the complexation reaction between Eu(III) and DiPTP. Furthermore, this TRLIL study may also allow ensuring that the observations made on mass spectra actually reflected the equilibrium in solution and not an intermediate state between liquid phase and gaseous phase. The investigation of europium(III) complexation with DiPTP by TRLIL described in this paper first led to highlight the exclusive formation of a 1:3 complex between europium(III) and the DiPTP ligand, specificity already pointed out by ESI-MS. Two different calculation methods, using either luminescence spectra and luminescence decay curves, have then been used to measure the conditional stability constant of the [Eu(DiPTP)(3)](3+) complex. Both methods gave similar results (log beta3(app)= 14.3 +/- 0.6 at pH 2.8) in good agreement with the one previously reported in ESI-MS studies (log beta3(app)= 14.0 +/- 0.6 at pH 2.8). Moreover, while considering the influence of temperature on the value of the stability constant, it was possible to estimate the enthalpy (DeltaH(beta3) = -29 +/- 3 kJ mol(-1) at pH 2.8) and entropy variations (DeltaS(beta3) = 173 +/- 10 J K(-1) mol(-1) at pH 2.8) associated with the [Eu(DiPTP)(3)](3+) complex formation.     

稀土冠醚类配合物的研究 XX: 三价及二价稀土硫氰酸盐与辛二酰双(4'-苯并-15-冠-5)配合物的合成和性质

在乙腈和二氯甲烷混合溶液中合成了三价稀土元素(La, Nd, Eu, Dy, Er, Yb)硫氰酸盐与辛二酰双(4'-苯并-15-冠-5)的六个新配合物。并在氩气氛中, 以四氢呋喃为溶剂, 锂-萘为还原剂, 制得了二价铕硫氰酸盐与辛二酰双(4'-苯并-15-冠-5)的固体配合物。通过元素分析、红外光谱、差热热重分析、荧光光谱、穆斯堡尔谱、电子自旋共振谱、还原性实验等研究了双冠醚与稀土离子的配位作用, 并讨论了三价和二价稀土配合物在物理化学性质上的差别。