Spectroscopic properties and design of highly luminescent lanthanide coordination complexes

Sá, Gilberto F. de; Malta, O.L.; Donegá, Celso de Mello; Simas, Alfredo M.; Longo, Ricardo L.; Santa-Cruz, P.A.; Silva, E.F da

doi:10.1016/s0010-8545(99)00054-5

Cited by 1,481 publications

(813 citation statements)

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“…The high coordination number of Eu allows simultaneous coordination of the metal ion by more than one multidentate ligand. This is also evidenced by the occurrences of ternary and quaternary lanthanide complexes (52). The multidentate character of DFOMTA even may foster the formation of polymer networks, in which Eu bridges between ligands.…”

Section: Resultsmentioning

confidence: 94%

Adsorption of Pb(II) and Eu(III) by Oxide Minerals in the Presence of Natural and Synthetic Hydroxamate Siderophores

Kraemer

Raymond

et al. 2002

Environ. Sci. Technol.

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Trihydroxamate siderophores have been proposed for use as mediators of actinide and heavy metal mobility in contaminated subsurface zones. These microbially produced ligands, common in terrestrial and marine environments, recently have been derivatized synthetically to enhance their affinity for transuranic metal cations. However, the interactions between these synthetic derivative and adsorbed trace metals have not been characterized. In this paper we compare a natural siderophore, desferrioxamine-B (DFO-B), with its actinide-specific catecholate derivative, N-(2,3-dihydroxy-4-(methylamido)benzoyl)-desferrioxamine-B (DFOMTA), as to their effect on the adsorption of Pb(II) and Eu(III) by goethite and boehmite. In the presence of 240 µM DFO-B, a strongly depleting effect on Eu(III) adsorption by goethite and boehmite occurred above pH 6. By contrast, almost total removal of Eu(III) from solution in the neutral to slightly acidic pH range was observed in the presence of either 10 or 100 µM DFOMTA, due primarily to the formation of metal-DFOMTA precipitates. Addition of DFOMTA caused an increase in Pb(II) adsorption by goethite below pH 5, but a decrease above pH 5, such that the Pb(II) adsorption edge in the presence of DFOMTA strongly resembled the DFOMTA adsorption envelope, which showed a maximum near pH 5 and decreasing adsorption toward lower and higher pH.

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Section: Resultsmentioning

confidence: 94%

Adsorption of Pb(II) and Eu(III) by Oxide Minerals in the Presence of Natural and Synthetic Hydroxamate Siderophores

Kraemer

Raymond

et al. 2002

Environ. Sci. Technol.

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“…The flexible PMMA/ionic liquid films were prepared by dissolving the europium(III) complex first in the pure ionic liquid [C 6 4 ] the complex was first dissolved in dichloromethane and a specific amount of this solution was added to the ionic liquid. A given amount of the europium(III)/ionic liquid solution was mixed with a solution of PMMA in tetrahydrofuran.…”

Section: Resultsmentioning

confidence: 99%

“…It was found that the processing temperature of the luminescent films is very critical. A first series of films doped with [C 6 mim][Eu(nta) 4 ] was prepared at 60 1C. Although these films were luminescent, the luminescence spectrum differed from what is expected for a tetrakis b-diketonate complex.…”

Section: Resultsmentioning

confidence: 99%

“…The synthetic procedure was slightly adapted after these negative results. A second series of [C 6 mim][Eu(nta) 4 ]-doped PMMA/ionic liquid films were therefore prepared at room temperature and in the dark. The films were prepared in the dark, because it is known that the lanthanide b-diketonate complexes have a low photostability in most organic solvents, including in the THF which was used for solvent processing of the thin films.…”

Section: Resultsmentioning

confidence: 99%

“…36 The b-diketonate ligands that they investigated were benzoyltrifluoroacetonate (btfac) and hexafluoroacetylacetonate (hfac). In the case of [Ln(btfac) 4 ] À they associated these bi-exponential decay curves with a partial dissociation of the lanthanide complex resulting in the presence of [Ln(btfac) 3 ] as well as [Ln(btfac) 4 ] À species in the doped polymers. The authors pointed to the influence of the solvent on the dissociation of the complexes.…”

Section: Resultsmentioning

confidence: 99%

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Ionic liquid as plasticizer for europium(iii)-doped luminescent poly(methyl methacrylate) films

Lunstroot

Driesen

Nockemann

et al. 2010

Phys. Chem. Chem. Phys.

148

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Flexible luminescent polymer films were obtained by doping europium(III) complexes in blends of poly(methyl methacrylate) (PMMA) and the ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C 6 3 ], where nta is 2-naphthoyltrifluoroacetonate, tta is 2-thenoyltrifluoroacetonate, phen is 1,10-phenanthroline, dpa is 2,6-pyridinedicarboxylate (dipicolinate) and choline is the 2-hydroxyethyltrimethyl ammonium cation. Bright red photoluminescence was observed for all the films upon irradiation with ultraviolet radiation. The luminescent films have been investigated by high-resolution steady-state luminescence spectroscopy and by time-resolved measurements. The polymer films doped with b-diketonate complexes are characterized by a very intense 5 D 0 -7 F 2 transition (up to 15 times more intense than the 5 D 0 -7 F 1 ) transition, whereas a marked feature of the PMMA films doped with [choline] 3 [Eu(dpa) 3 ] is the long lifetime of the 5 D 0 excited state (1.8 ms).

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High-Spin Iron(II) as a Semitransparent Partner for Tuning Europium(III) Luminescence in Heterodimetallic d-f Complexes

et al. 2001

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The segmental ligand 2-[6-(N,N-diethylcarbamoyl)pyridin-2-yl]-1,1'-dimethyl-5,5'-methylene-2'-(6-methylpyridine-2-yl)bis[1H-benzimidazole] (L3) reacts with a stoichiometric mixture of LnIII (Ln = La, Eu, Gd) and M(II) (M = Zn, Fe) in acetonitrile to produce selectively the heterodimetallic triple-stranded helicates (HHH)-[LnM(L3)3]5+. In these complexes, M(II) is pseudooctahedrally coordinated by the three wrapped bidentate binding units, thus forming a noncovalent tripod which organizes the three unsymmetrical tridentate segments to give ninefold coordination to LnIII. The introduction of a methyl group at the 6 position of the terminal pyridine in L3 sterically reduces the complexing ability of the bidentate segment for M(II). Spectroscopic (ESI-MS, UV/Vis/NIR, NMR), magnetic and electrochemical measurements show that 1) the head-to-head-to-head triple helical complexes (HHH)-[LnM(L3)3]5+ are quantitatively formed in solution only for ligand concentrations larger than 0.01 M, 2) FeII adopts a pure high-spin electronic configuration in (HHH)-[LnFe(L3)3]5+ and 3) the FeII/FeIII oxidation process is prevented by steric constraints. Detailed photophysical studies of (HHH)-[Eu-Zn(L3)3]5+ confirm that the pseudotricapped trigonal-prismatic lanthanide coordination site is not affected by the methyl groups bound to the terminal pyridine, thus leading to significant Eu-centered emission upon UV irradiation. In (HHH)-[EuFe(L3)3]5+, a resonant intramolecular Eu-->Fe(II)hs energy transfer partially quenches the Eu-centered luminescence; however, the residual red emission demonstrates that high-spin iron(II) is compatible with the sensitization of Eu(III) in heterodimetallic d-f complexes. The influence of the electronic configuration of Fe(II) on the efficiency of Eu(III)-->Fe(II) energy-transfer processes is discussed together with its consequence for the design of optically active spin-crossover supramolecular devices.

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Spectroscopic properties and design of highly luminescent lanthanide coordination complexes

Cited by 1,481 publications

References 94 publications

Adsorption of Pb(II) and Eu(III) by Oxide Minerals in the Presence of Natural and Synthetic Hydroxamate Siderophores

Adsorption of Pb(II) and Eu(III) by Oxide Minerals in the Presence of Natural and Synthetic Hydroxamate Siderophores

Ionic liquid as plasticizer for europium(iii)-doped luminescent poly(methyl methacrylate) films

High-Spin Iron(II) as a Semitransparent Partner for Tuning Europium(III) Luminescence in Heterodimetallic d-f Complexes

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