Influence of dipicolinate ligands on the spectroscopic properties of europium(III) in solution

Binnemans, Koen; Herck, Kristine Van; Görller‐Walrand, Christiane

doi:10.1016/s0009-2614(97)00012-2

Cited by 132 publications

(96 citation statements)

References 23 publications

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“…. This was first observed in the absorption spectra of these complexes [156], and later in the luminescence spectra ( Figure 4) [157]. gives rise to other anomalies in the crystal-field spectra, as described by Chen and Liu [148].…”

Section: Transitionmentioning

confidence: 55%

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Interpretation of europium(III) spectra

Binnemans

2015

Coordination Chemistry Reviews

2,346

108

1,912

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Section: Transitionmentioning

confidence: 55%

“…At lower temperatures, the nine-coordinate species dominates the mixture, whereas the contribution of the eight-coordinate species increases with increasing temperatures. Reproduced with permission from reference [156]. Copyright 1997 Elsevier.…”

Section: Transitions Within the 7 F Ground Termmentioning

confidence: 99%

Interpretation of europium(III) spectra

Binnemans

2015

Coordination Chemistry Reviews

2,346

108

1,912

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“…Moreover, when 5 D 1±3 Eu III levels act as energy acceptors, they decay non radiatively to the lower-lying 5 D 0 state that is the predominant emitting state and that gives rise to the characteristic lifetime and emission spectrum of the Eu 3 ion [20]. Looking Concerning the radiative rate constants, we can notice that the k r values are higher than those reported for the free Eu 3 and Tb 3 ions, 190 and 110 s À1 respectively [2b], reflecting the favorable effect of the organic ligands on the overall radiative decay probability of these ions [31]. These estimated k r values are in the range of those reported in recent literature for organocomplexes of Eu 3 (400 s À1 < k r < 600 s À1 ) and Tb 3 (250 s À1 < k r < 500 s À1 ) [11] [15b] (and refs.…”

mentioning

confidence: 88%

Luminescence of Eu3+ and Tb3+ Complexes of Two Macrobicyclic Ligands Derived from a Tetralactam Ring and a Chromophoric Antenna

Galaup

Azéma

Tisnès

et al. 2002

HCA

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Two macrobicyclic ligands derived from an 18-membered tetralactam ring and 2,2'-bipyridine or 2,6-bis(pyrazol-1-yl)pyridine moieties, 1 and 2, respectively, form stable complexes with Gd III , Eu III , and Tb III ions in aqueous solution. The ligand-based luminescence is retained in the Gd III cryptates, whereas this radiative deactivation is quenched in the Eu III and Tb III cryptates by ligand-to-metal energy transfer, resulting in the usual metal-centered emission spectra. Singlet-and triplet-state energies, emission-decay lifetimes, and luminescence yields were measured. [Tb & 1] 3 cryptate shows a long luminescence lifetime (t 1.12 ms) and a very high metal luminescence quantum yield (F 0.25) in comparison with those reported in the literature for Tb 3 complexes sensitized by a bipyridine chromophore. By comparison to [Ln & 1] 3 , [Ln & 2] 3 presents markedly lower luminescence properties, due to worse interaction between the 2,6-bis(pyrazol-1-yl)pyridine unit and the metal ion. Moreover, the luminescent metal and the triplet ligand energy levels of [Eu & 2] 3 do not match. The effects of H 2 O molecules coordinated to the metal centre and of thermally activated decay processes on nonradiative deactivation to the ground-state are also reported.Introduction. ± The increasing interest in Eu 3 , Tb 3 luminescent probes is fully justified by their high sensitivity, especially in biological systems. These ions exhibit relatively efficient long-lived luminescence (ms range) when raised to their excited states, which permits easy temporal resolution from the short-lived (sub-ms range) fluorescence background of biological materials [1]. Eu 3 and Tb 3 ions are used as structural and analytical luminescent probes and stains for biomolecular systems [2], and the luminescence of Eu 3 and Tb 3 organocomplexes is exploited in bioanalytical assays such as immunoassays, nucleic acid hybridizations, enzyme assays, or receptor assays (for recent reviews, see [3]). Lanthanide complexes have also been shown to be excellent donors in luminescence resonance energy transfer (LRET) for homogeneous immunoassays [4] and to measure both static and time-varying distances [5]. In addition, the use of macrocyclic Eu and Tb complexes as luminescent sensors for pO 2 , pH and other bioactive ions has been recently reported [6].In attempts to optimize the luminescent properties of Eu 3 and Tb 3 complexes, a great deal of effort has been devoted to the synthesis of a range of different ligands. Many photoactive ligands, including those based on b-diketones (see, e.g., [7]),

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“…The high polarisability of pyridine nitrogen atoms means that their binding with Eu 3+ ion, which occurs in the crystal, results in an increase of the 5 D 0 Ǟ 7 F 2 transition intensity, as reported previously for a similar europium complex with ligands containing a pyridine group. [20] This may suggest that coordination of the pyridine nitrogen atoms to Eu III ion does not take place in solution.…”

Section: Emission Spectramentioning

confidence: 99%

Unusual Coordination Behaviour of a Phosphonate‐ and Pyridine‐Containing Ligand in a Stable Lanthanide Complex

et al. 2010

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An experimental study of the coordination of lanthanide ions with {ethane-1,2-diylbis[imino(pyridin-2-ylmethanediyl)]}-bis(phosphonic acid), a ligand containing phosphonate and pyridine arms attached to the well-known ethylenediamine scaffold, is reported. The X-ray crystal structure of an anionic, octacoordinate Eu III complex of the formula [C(NH 2 )] 6 [Eu 2 (L) 2 (CO 3 ) 2 ]·8H 2 O has been obtained and found to contain cyclic dimeric complex anions in which the coordination environment of each Eu III ion is composed of three oxygen atoms from phosphonate groups, two nitrogen atoms from imino groups and one nitrogen atom from a pyridine group, a combination that has seldom been observed for Ln III complexes. In order to check the coordination behaviour of the ligand, an investigation of the complexes in solution has been performed, which revealed a different coordination mode. The protonation constants of the free ligand and the

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Influence of dipicolinate ligands on the spectroscopic properties of europium(III) in solution

Cited by 132 publications

References 23 publications

Interpretation of europium(III) spectra

Interpretation of europium(III) spectra

Luminescence of Eu3+ and Tb3+ Complexes of Two Macrobicyclic Ligands Derived from a Tetralactam Ring and a Chromophoric Antenna

Unusual Coordination Behaviour of a Phosphonate‐ and Pyridine‐Containing Ligand in a Stable Lanthanide Complex

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