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Europium Luminescence: Electronic Densities and Superdelocalizabilities for a Unique Adjustment of Theoretical Intensity Parameters.

Dutra JD, Lima NB, Freire RO, Simas AM - Sci Rep (2015)

Bottom Line: We advance the concept that the charge factors of the simple overlap model and the polarizabilities of Judd-Ofelt theory for the luminescence of europium complexes can be effectively and uniquely modeled by perturbation theory on the semiempirical electronic wave function of the complex.An important consequence is that the terms of the intensity parameters related to dynamic coupling and electric dipole mechanisms will be unique.Hence, the important energy transfer rates will also be unique, leading to a single predicted intensity parameter for the (5)D0→(7)F6 transition.

View Article: PubMed Central - PubMed

Affiliation: Pople Computational Chemistry Laboratory, Departamento de Química, CCET, UFS, 49100-000, Aracaju, SE, Brazil.

ABSTRACT
We advance the concept that the charge factors of the simple overlap model and the polarizabilities of Judd-Ofelt theory for the luminescence of europium complexes can be effectively and uniquely modeled by perturbation theory on the semiempirical electronic wave function of the complex. With only three adjustable constants, we introduce expressions that relate: (i) the charge factors to electronic densities, and (ii) the polarizabilities to superdelocalizabilities that we derived specifically for this purpose. The three constants are then adjusted iteratively until the calculated intensity parameters, corresponding to the (5)D0→(7)F2 and (5)D0→(7)F4 transitions, converge to the experimentally determined ones. This adjustment yields a single unique set of only three constants per complex and semiempirical model used. From these constants, we then define a binary outcome acceptance attribute for the adjustment, and show that when the adjustment is acceptable, the predicted geometry is, in average, closer to the experimental one. An important consequence is that the terms of the intensity parameters related to dynamic coupling and electric dipole mechanisms will be unique. Hence, the important energy transfer rates will also be unique, leading to a single predicted intensity parameter for the (5)D0→(7)F6 transition.

No MeSH data available.


Related in: MedlinePlus

Perspective view of the crystallographic geometry of complex Eu(BTFA)3(4,4-BPY)(EtOH), GIPCAK.Red spheres represent oxygen atoms, blue spheres represent nitrogen atoms, and green sticks represent fluorine. The largest sphere in the center represents the europium atom.
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f1: Perspective view of the crystallographic geometry of complex Eu(BTFA)3(4,4-BPY)(EtOH), GIPCAK.Red spheres represent oxygen atoms, blue spheres represent nitrogen atoms, and green sticks represent fluorine. The largest sphere in the center represents the europium atom.

Mentions: To exemplify how the new methodology functions, consider the crystallographic structure of the complex of CSD code GIPCAK, Eu(BTFA)3(4,4-BPY)(EtOH), shown in Fig. 1, where BTFA stands for 4,4,4-trifluoro-1-phenyl-2,4-butanedione, and 4,4-BPY for 4,4′-bipyridine. We then carried out a single point Sparkle/RM1 calculation in order to obtain the ZDO electronic densities and electrophilic superdelocalizabilities at the directly coordinating atoms of the ligands to be used in the fitting procedure. We also carried out single point RM1 model for Eu(III) calculations to obtain the ZDO electronic densities and electrophilic superdelocalizabilities, so that we can now compare the electronic properties results, at the crystallographic geometry, from a Sparkle Model with those from the RM1 model for Eu(III), which has valence orbitals at the europium ion center.


Europium Luminescence: Electronic Densities and Superdelocalizabilities for a Unique Adjustment of Theoretical Intensity Parameters.

Dutra JD, Lima NB, Freire RO, Simas AM - Sci Rep (2015)

Perspective view of the crystallographic geometry of complex Eu(BTFA)3(4,4-BPY)(EtOH), GIPCAK.Red spheres represent oxygen atoms, blue spheres represent nitrogen atoms, and green sticks represent fluorine. The largest sphere in the center represents the europium atom.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4557129&req=5

f1: Perspective view of the crystallographic geometry of complex Eu(BTFA)3(4,4-BPY)(EtOH), GIPCAK.Red spheres represent oxygen atoms, blue spheres represent nitrogen atoms, and green sticks represent fluorine. The largest sphere in the center represents the europium atom.
Mentions: To exemplify how the new methodology functions, consider the crystallographic structure of the complex of CSD code GIPCAK, Eu(BTFA)3(4,4-BPY)(EtOH), shown in Fig. 1, where BTFA stands for 4,4,4-trifluoro-1-phenyl-2,4-butanedione, and 4,4-BPY for 4,4′-bipyridine. We then carried out a single point Sparkle/RM1 calculation in order to obtain the ZDO electronic densities and electrophilic superdelocalizabilities at the directly coordinating atoms of the ligands to be used in the fitting procedure. We also carried out single point RM1 model for Eu(III) calculations to obtain the ZDO electronic densities and electrophilic superdelocalizabilities, so that we can now compare the electronic properties results, at the crystallographic geometry, from a Sparkle Model with those from the RM1 model for Eu(III), which has valence orbitals at the europium ion center.

Bottom Line: We advance the concept that the charge factors of the simple overlap model and the polarizabilities of Judd-Ofelt theory for the luminescence of europium complexes can be effectively and uniquely modeled by perturbation theory on the semiempirical electronic wave function of the complex.An important consequence is that the terms of the intensity parameters related to dynamic coupling and electric dipole mechanisms will be unique.Hence, the important energy transfer rates will also be unique, leading to a single predicted intensity parameter for the (5)D0→(7)F6 transition.

View Article: PubMed Central - PubMed

Affiliation: Pople Computational Chemistry Laboratory, Departamento de Química, CCET, UFS, 49100-000, Aracaju, SE, Brazil.

ABSTRACT
We advance the concept that the charge factors of the simple overlap model and the polarizabilities of Judd-Ofelt theory for the luminescence of europium complexes can be effectively and uniquely modeled by perturbation theory on the semiempirical electronic wave function of the complex. With only three adjustable constants, we introduce expressions that relate: (i) the charge factors to electronic densities, and (ii) the polarizabilities to superdelocalizabilities that we derived specifically for this purpose. The three constants are then adjusted iteratively until the calculated intensity parameters, corresponding to the (5)D0→(7)F2 and (5)D0→(7)F4 transitions, converge to the experimentally determined ones. This adjustment yields a single unique set of only three constants per complex and semiempirical model used. From these constants, we then define a binary outcome acceptance attribute for the adjustment, and show that when the adjustment is acceptable, the predicted geometry is, in average, closer to the experimental one. An important consequence is that the terms of the intensity parameters related to dynamic coupling and electric dipole mechanisms will be unique. Hence, the important energy transfer rates will also be unique, leading to a single predicted intensity parameter for the (5)D0→(7)F6 transition.

No MeSH data available.


Related in: MedlinePlus