Highly Luminescent Lanthanide Complexes of 1-Hydroxy-2-pyridinones

Moore, Evan G.; Xu, Jide; Jocher, Christoph J.; Castro-Rodríguez, Ingrid; Raymond, Kenneth N.

doi:10.1021/ic702144n

Cited by 70 publications

(126 citation statements)

References 43 publications

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“…The maximum absorption, at ca. 342 nm, is significantly red shifted compared to aliphatic bridged analogs 8,9 and is in excellent agreement with the TD-DFT calculation. This is consistent with the expectation that the aryl bridged ligand, compared with the previously reported aliphatic bridged complexes, has a more delocalized electronic excited state.…”

supporting

confidence: 84%

“…This is consistent with the expectation that the aryl bridged ligand, compared with the previously reported aliphatic bridged complexes, has a more delocalized electronic excited state. 8,9 The luminescence spectrum is typical of those for the Eu(III) complexes. Notably, the 5 D 0 → 7 F 2 hypersensitive transition is very intense (83 % of the Eu(III) spectral intensity), resulting in almost pure red luminescence (λ em = 612 nm).…”

Section: Nih-pa Author Manuscriptmentioning

confidence: 85%

“…Despite this obvious structural difference, the coordination polyhedron, as determined by shape analysis, 8 remains closest to the bicapped trigonal prismatic (C 2v ) geometry, and the observed coordinate bondlengths (Eu-O = 2.393 Å) are similar to previous reports. 8,9 Solution thermodynamic experiments assessed the stability of the (5) 9 ), these data do not follow the usual trend that more acidic ligands (of the same chelate group) will form weaker metal complexes. 12 Instead, while the most acidic ligand is o-Phen-1,2-HOPO, it is evident that the 5LI-1,2-HOPO ligand forms the weakest ML 2 chelate.…”

Section: Introductionmentioning

confidence: 89%

“…Info). 8 The resulting T 0 energy was evaluated to be ca. 20,964 cm −1 , which is notably in excellent agreement with the value estimated by TD-DFT methods for the [Na(6-PhenylAmide-1,2-HOPO)] complex (T 0-0 2 0,700 cm −1 ).…”

Section: Nih-pa Author Manuscriptmentioning

confidence: 99%

“…This ligand bridges two 1,2-HOPO units via an aryl group, yielding a higher degree of conjugation when compared to previously reported alkyl linkages. [8,9] The resultant stability constants and optical properties of this new ligand architecture are compared to the parent 5LI-8 and 5LIO-1,2-HOPO 9 compounds.* To whom correspondence should be addressed. raymond@socrates.berkeley.edu.…”

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confidence: 99%

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Aryl-Bridged 1-Hydroxypyridin-2-one: Sensitizer Ligands for Eu(III)

D’Aléo

Moore

et al. 2008

Inorg. Chem.

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The synthesis, crystal structure, solution stability and photophysical properties of an aryl group bridging two 1-hydroxypyridin-2-one units complexed to Eu(III) are reported. The results show that this backbone unit increases the rigidity of the ensuing complex, and also the conjugation of the ligand. As a result of the latter, the singlet absorption energy is decreased, along with the energy of the lowest excited triplet state. The resulting efficiency of sensitization for the Eu(III) ion is influenced by these phenomena, yielding an overall quantum yield of 6.2% in aqueous solution. The kinetic parameters arising from the luminescence data reveal an enhanced nonradiative decay rate for this compound when compared to previously reported aliphatic bridges.Due to the Laporte forbidden character and intraconfigurational nature of the 4f transitions, 1 luminescence from lanthanide cations is typically highly monochromatic, exhibits long-lived excited state lifetimes when compared to organic compounds, and is usually insensitive to quenching by molecular oxygen, making these metal ions ideal for applications as fluorescent probes, 2 optical signal amplifiers 3 or light emitting diodes. 4 Unfortunately, for the same reason, the molar absorption coefficient of lanthanide transitions is very small (less than 10 M −1 .cm −1 ). 5 To obviate this problem, organic ligands having a large molar absorption coefficient can be coordinated to the lanthanide ion, resulting in sensitized emission through the so-called antenna effect. The mechanism of antenna sensitization is comprised of three differing steps: the initial excitation of the ligand, followed by intersystem crossing to give an excited triplet state, then subsequent energy transfer to yield the metal centered excited state which emits light. 1,[5][6][7] For this mechanism, the energy of the sensitizing triplet state relative to the 5 D 0 or 5 D 1 excited states of Eu(III) is one of the critical parameters which can be tuned in order to optimize the system. Furthermore, the rate of intersystem crossing, energy transfer and radiative vs. non-radiative decay of the metal must be considered, and these rates may all be influenced by the geometry and chemical structure of the sensitizing ligand. We report here the synthesis, crystal structure, solution stability and photophysical properties of a new 1-hydroxypyridin-2-one (1,2-HOPO) based chelator, o-Phen-1,2-HOPO (Chart 1), acting as a tetradentate ligand to form an ML 2 complex with Eu(III). This ligand bridges two 1,2-HOPO units via an aryl group, yielding a higher degree of conjugation when compared to previously reported alkyl linkages. [8,9] The resultant stability constants and optical properties of this new ligand architecture are compared to the parent 5LI-8 and 5LIO-1,2-HOPO 9 compounds.* To whom correspondence should be addressed. raymond@socrates.berkeley.edu. Fax: +1 (510) The o-Phen-1,2-HOPO ligand is readily prepared by reaction of the benzyl-protected 1,2-HOPO-6-carboxylic acid intermediate prepare...

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supporting

confidence: 84%

Section: Nih-pa Author Manuscriptmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 89%

Section: Nih-pa Author Manuscriptmentioning

confidence: 99%

mentioning

confidence: 99%

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Aryl-Bridged 1-Hydroxypyridin-2-one: Sensitizer Ligands for Eu(III)

D’Aléo

Moore

et al. 2008

Inorg. Chem.

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Structure, Dynamics, and Computational Studies of Lanthanide‐Based Contrast Agents

Peters

Djanashvili

Geraldes

et al. 2013

The Chemistry of Contrast Agents in Medical Magnetic Resonance Imaging

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Catechol‐Based Biomimetic Functional Materials

Saiz‐Poseu²,

et al. 2012

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Abstract.Catechols are found in nature taking part in a remarkably broad scope of biochemical processes and functions. Though not exclusively, such versatility may be traced back to several properties uniquely found together in the o -dihydroxyaryl chemical function; namely, its ability to establish reversible equilibria at moderate redox potentials and pHs and to irreversibly cross-link through complex oxidation mechanisms; its excellent chelating properties, greatly exemplifi ed by, but by no means exclusive, to the binding of Fe 3 + ; and the diverse modes of interaction of the vicinal hydroxyl groups with all kinds of surfaces of remarkably different chemical and physical nature. Thanks to this diversity, catechols can be found either as simple molecular systems, forming part of supramolacular structures, coordinated to different metal ions or as macromolecules mostly arising from polymerization mechanisms through covalent bonds. Such versatility has allowed catechols to participate in several natural processes and functions that range from the adhesive properties of marine organisms to the storage of some transition metal ions. As a result of such an astonishing range of functionalities, catechol-based systems have in recent years been subject to intense research, aimed at mimicking these natural systems in order to develop new functional materials and coatings. A comprehensive review of these studies is discussed in this paper.

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Highly Luminescent Lanthanide Complexes of 1-Hydroxy-2-pyridinones

Cited by 70 publications

References 43 publications

Aryl-Bridged 1-Hydroxypyridin-2-one: Sensitizer Ligands for Eu(III)

Aryl-Bridged 1-Hydroxypyridin-2-one: Sensitizer Ligands for Eu(III)

Structure, Dynamics, and Computational Studies of Lanthanide‐Based Contrast Agents

Catechol‐Based Biomimetic Functional Materials

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