Luminescence and structure of europium compounds

Vicentini, G.; Zinner, L.B.; Zukerman-Schpector, Júlio; Zinner, K.

doi:10.1016/s0010-8545(99)00220-9

Cited by 269 publications

(130 citation statements)

References 46 publications

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“…The europium complex was prepared by the addition of an aqueous solution of the lanthanide salt Eu(NO 3 …”

Section: Preparation Of [mentioning

confidence: 99%

“…Some organic ligands can act as light collectors (antennae) transferring absorbed energy intra-molecularly to lanthanide cations (emitters), yielding highly luminescent lanthanide complexes [1][2][3]. In this context, we studied the coordination of aromatic ambidentate ligands to lanthanide ions [4].…”

Section: Introductionmentioning

confidence: 99%

“…The crystal structures of transition-metal complexes of dihydroxybenzoic acids (2, (2, 4 ]·3H 2 O [11], [Cu(2,6-Hdhb) 2 (2, 3 (H 2 O) 4 ]·2H 2 O [14]. In these complexes, 2,3-H 2 dhb act as a catecholato type chelate, whereas 2,6-H 2 dhb shows a more versatile coordination mode (either using both the carboxylate group and an adjacent hydroxyl group in a salicylato type chelate, or the carboxylate group in a monodentate or bidentate fashion).…”

Section: Introductionmentioning

confidence: 99%

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Novel luminescent materials based on silica doped with an europium(III) complex of 2,6-dihydroxybenzoic acid

Soares‐Santos

Nogueira

Paz

et al. 2004

Journal of Alloys and Compounds

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Novel luminescent materials were prepared by introducing a new Eu 3+ complex of 2,6-dihydroxybenzoic acid (2,6-H 2 dhb) into a silica gel made by the sol-gel method. The crystal structure of the resulting complex [ n Bu 4 N] 2 [Eu(2,6-Hdhb) 5 (H 2 O) 2 ] was determined using single-crystal X-ray diffraction. The compound was further characterised using FTIR, FT-Raman and elemental analysis. Photoluminescence measurements were performed for the isolated Eu(III) 2,6-dihydroxybenzoate complex and also for the related silica composite material.

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“…The europium complex was prepared by the addition of an aqueous solution of the lanthanide salt Eu(NO 3 …”

Section: Preparation Of [mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Novel luminescent materials based on silica doped with an europium(III) complex of 2,6-dihydroxybenzoic acid

Soares‐Santos

Nogueira

Paz

et al. 2004

Journal of Alloys and Compounds

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“…O estudo das propriedades espectroscópicas e a avaliação dos parâmetros opticos-eletrônicos de complexos contendo íons lantanídeos tem sido largamente investigado na literatura [1][2][3][4][5][6][7][8][9] devido às diversas possibilidades de aplicações, como por exemplo em lasers 10 , sensores luminescentes para espécies químicas 11 , dosímetros UV 12 , etc. O estudo da polarizabilidade eletrônica pode ser aplicado no acompanhamento dos estudos eletrônicos dos estados intermediários de transição, em processos fotoquímicos e em reações químicas fotocatalisadas de interesse na obtenção de substâncias estereoseletivas 13 .…”

Section: Introductionunclassified

Propriedades espectroscópicas e parâmetros ópticos-eletrônicos dos complexos Ln(NO3)3.2DTPO.4H2O (Ln = Nd e Er)

Pedrosa¹,

Pimentel²,

Batista³

et al. 2004

Quím. Nova

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Recebido em 6/1/03; aceito em 12/12/03 SPECTROSCOPIC PROPERTIES AND ELECTRONIC-OPTIC PARAMETERS OF COMPLEXES Ln(NO 3 ) 3 .2DTPO.4H 2 O (Ln = Nd and Er). Complexes with the composition Ln(NO 3 ) 3 .2DTPO.4H 2 O (Ln = Nd and Er) were synthesized and characterized by infrared and visible absorption spectra (solid state and solution). The results of the absorption spectra in the solid state suggest that metal-ligand bonds are essentially electrostatic in all complexes. The absorption spectra of the nitrate salt solution presented smaller values of the oscillator strength when compared to the spectra of the complexes in the same solvent.Keywords: spectroscopic properties; neodymium; erbium. INTRODUÇÃOO estudo das propriedades espectroscópicas e a avaliação dos parâmetros opticos-eletrônicos de complexos contendo íons lantanídeos tem sido largamente investigado na literatura 1-9 devido às diversas possibilidades de aplicações, como por exemplo em lasers 10 , sensores luminescentes para espécies químicas 11 , dosímetros UV 12 , etc. O estudo da polarizabilidade eletrônica pode ser aplicado no acompanhamento dos estudos eletrônicos dos estados intermediários de transição, em processos fotoquímicos e em reações químicas fotocatalisadas de interesse na obtenção de substâncias estereoseletivas 13 . Um estudo detalhado dos mecanismos de excitação de moléculas pode ser útil no acompanhamento dos fenômenos de obtenção e controle de espécies no estado do complexo ativado, através da avaliação da deformação da nuvem eletrônica das espécies opticamente ativas [5][6][7] . Átomos e moléculas ao serem submetidos a um campo elétrico adquirem um momento de dipolo induzido, deslocando as densidades de cargas positivas e negativas modificando, assim, a sua distribuição eletrônica relativa à posição do núcleo e, conseqüentemente, distorcendo sua geometria molecular. A polarizabilidade avalia a facilidade que uma molécula tem em mudar sua configuração ao interagir com a radiação eletromagnética, podendo ser avaliada pela razão entre o momento de dipolo induzido, µ, e o campo responsável pelo momento, ε O, de forma que 14-15 :onde: α = polarizabilidade, µ ok = momento de dipolo elétrico induzido do sistema, ε ok = campo elétrico aplicado A polarizabilidade total de um sistema é dada pelo somatório das polarizabilidades: i) atômica (soma vetorial da contribuição dos elétrons em um áto-mo) ou molecular (soma vetorial da contribuição de todos os elétrons dos átomos em uma molécula);ii) eletrônica (distorção da nuvem ocasionada por elétrons fotoativados) e iii) de orientação (dependência da distorção da nuvem eletrônica com a temperatura, na presença de um campo elétrico). É possível avaliar as polarizabilidades eletrônicas, usando a definição da força do oscilador de uma transição dipolo elétrico para o elétron oscilando em fase com a radiação incidente, a partir da expressão:(2) e, para o elétron oscilando fora de fase:Me e e são a massa do elétron e a carga, respectivamente; P ok a força do oscilador; ν ok a freqüência do baricentro da tra...

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“…Lanthanide complexes of pyridine-2,6-dicarboxylic acid (PDA) and their substituted derivatives have interesting photophysical properties [23][24][25]. PDA has two carboxylic functional groups and a nitrogen atom with nonbonding electrons to form stable complexes with metal ions.…”

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confidence: 99%

Synthesis and characterization of bifunctional terbium complex-based nanoparticles

Lü

Huang

et al. 2012

Chin. Sci. Bull.

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Novel bifunctional terbium complex-based nanoparticles were developed using a modified Stöber method and a layer-by-layer assembly process. A magnetic core of Fe 3 O 4 nanoparticles was coated with a silica shell to form the first layer. Then a ternary Tb 3+ complex (TESPPA-Tb), which acted as a luminescent marker, was covalently bound to the silica surface by stable Si-O-Si bonds. The TESPPA monomer was synthesized by binding pyridine 2,6-dicarboxylic acid to 3-aminopropyltriethoxysilane, which was used as a ligand for coordination with the Tb 3+ ions. An outer shell of silica was applied to the nanoparticles to allow for versatility with surface functionalization. The nanoparticles were characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, vibration sample magnetometer, and photoluminescence spectroscopy. The bifunctional nanoparticles exhibited favorable superparamagnetic behavior and photoluminescence properties of Tb . Superparamagnetic NPs can be attracted by a magnetic field, but retain no residual magnetism after the field is removed, which means they can be easily separated from a matrix without agglomeration after removal of the magnetic field. Microor nanocomposites that combine superparamagnetic and optical properties into a single system have potential applications in the biomedical and biopharmaceutical fields and have attracted much attention [10]. Luminescent NPs such as quantum dots and dye-doped NPs have been used as biolabels in bioassays, and these have advantages over traditional fluorophores [11][12][13]. However, quantum dots have poor water-solubility, difficult surface conjugation chemistry, and possible toxicity in vivo, and are still under investigation [14,15]. Organic dye-doped NPs have broad emission and small Stokes shift, which results in interference between the excitation and emission signals. These limitations hinder the application of quantum dots and dye-doped NPs.Compared with these fluorophores, luminescent lanthanide complexes, especially those of Tb 3+ and Eu 3+ , have large Stokes shifts and strong narrow emission bands in the visible region, which are crucial for low detection limits and high sensitivity in fluorescence detection. They also have long fluorescence lifetimes (micro-to milliseconds range), which allow the removal of background fluorescence and increased assay sensitivity in time-resolved measurements, and can provide accurate and highly sensitive quantification

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Luminescence and structure of europium compounds

Cited by 269 publications

References 46 publications

Novel luminescent materials based on silica doped with an europium(III) complex of 2,6-dihydroxybenzoic acid

Novel luminescent materials based on silica doped with an europium(III) complex of 2,6-dihydroxybenzoic acid

Propriedades espectroscópicas e parâmetros ópticos-eletrônicos dos complexos Ln(NO3)3.2DTPO.4H2O (Ln = Nd e Er)

Synthesis and characterization of bifunctional terbium complex-based nanoparticles

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