Synthesis, sparkle model and spectroscopic studies of the Eu(hfc)3·bipyO2 complex

Mesquita, Maria Eliane de; Júnior, Severino Alves; Silva, F.R.G. e; Santos, M.A. Couto dos; Freire, Ricardo O.; Júnior, N.B.C.; Sá, Gilberto F. de

doi:10.1016/j.jallcom.2003.11.100

Cited by 20 publications

(9 citation statements)

References 24 publications

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“…Our research group has been developing over the past few years a number of theoretical approaches which predict very well several spectroscopic properties such as singlet and triplet energy positions, − electronic spectra of lanthanide complexes, − ligand field parameters, B q k , − 4 f −4 f intensity parameters, Ω λ (λ = 2, 4, and 6), − energy transfer rates, W ET , between the lanthanide trivalent ions and the ligand, quantum yields, and luminescence efficiencies for these complexes. − Following our interest in the synthesis and characterization of MOF-type materials containing lanthanide centers, − in this paper we wish to report a detailed photophysical investigation of the properties of the 3D [Ln 2 (MELL)(H 2 O) 6 ] materials (where Ln 3+ = Eu 3+ , Tb 3+ , and Gd 3+ ; hereafter designated as (1) , (2) , and (3) ). The structure of the La-based material has been described by Williams and collaborators, and recently Lin reported the surfactant-assisted synthesis of the nanoscale [Gd 2 (MELL)(H 2 O) 6 ] and demonstrated the potential utility in magnetic resonance imaging (MRI) .…”

Section: Introductionmentioning

confidence: 99%

Modeling, Structural, and Spectroscopic Studies of Lanthanide-Organic Frameworks

et al. 2009

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In this paper, we report the hydrothermal synthesis of three lanthanide-organic framework materials using as primary building blocks the metallic centers Eu(3+), Tb(3+), and Gd(3+) and residues of mellitic acid: [Ln(2)(MELL)(H(2)O)(6)] (where Ln(3+) = Eu(3+), Tb(3+), and Gd(3); hereafter designated as (1), (2) and (3)). Structural characterization encompasses single-crystal X-ray diffraction studies, thermal analysis, and vibrational spectroscopy, plus detailed investigations on the experimental and predicted (using the Sparkle/AM1 model) photophysical luminescent properties. Crystallographic investigations showed that the compounds are all isostructural, crystallizing in the orthorhombic space group Pnnm and structurally identical to the lanthanum 3D material reported by the group of Williams. (2) is highly photoluminescent, as confirmed by the measured quantum yield and lifetime (37% and 0.74 ms, respectively). The intensity parameters (Omega(2), Omega(4), and Omega(6)) of (1) were first calculated using the Sparkle/AM1 structures and then employed in the calculation of the rates of energy transfer (W(ET)) and back-transfer (W(BT)). Intensity parameters were used to predict the radiative decay rate. The calculated quantum yield derived from the Sparkle/AM1 structures was approximately 16%, and the experimental value was 8%. We attribute the registered differences to the fact that the theoretical model does not consider the vibronic coupling with O-H oscillators from coordinated water molecules. These results clearly attest for the efficacy of the theoretical models employed in all calculations and open a new window of interesting possibilities for the design in silico of novel and highly efficient lanthanide-organic frameworks.

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Section: Introductionmentioning

confidence: 99%

Modeling, Structural, and Spectroscopic Studies of Lanthanide-Organic Frameworks

et al. 2009

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“…For example, quantum chemical methods are able to calculate the ground state geometry of lanthanide centers, and first principles methods using effective core potentials (ECPs) have proven their effectiveness in lanthanide chemistry. − Nevertheless, these methodologies are computationally very demanding and, thus, inappropriate for expanded systems such as MOFs. Sparkle/AM1 algorithms are instead based on a sophisticated parametrization scheme for semiempirical calculations, allowing the prediction of coordination geometries whose accuracy is comparable to those obtained from ab initio/ECP calculations but at much smaller expense of computational power. − The Sparkle/AM1 model has been successfully applied to the prediction of the ground state geometries of lanthanide complexes, the corresponding ligand field parameters, − plus a number of other spectroscopic properties such as electronic spectrum, singlet and triplet energy positions, − and intensity parameters. − By using the two latter series of calculated parameters, we have recently built up rate equations involving energy transfer mechanisms which allowed the determination of PL efficiencies and quantum yields, , and, in a more recent study, we have reported the design of a highly photoluminescent europium complex simply based on theoretical studies …”

Section: Introductionmentioning

confidence: 99%

Theoretical and Experimental Studies of the Photoluminescent Properties of the Coordination Polymer [Eu(DPA)(HDPA)(H₂O)₂]·4H₂O

et al. 2008

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We report on the hydrothermal synthesis of the [Eu(DPA)(HDPA)(H(2)O)(2)].4H(2)O lanthanide-organic framework (where H2DPA stands for pyridine-2,6-dicarboxylic acid), its full structural characterization including single-crystal X-ray diffraction and vibrational spectroscopy studies, plus detailed investigations on the experimental and predicted (using the Sparkle/PM3 model) photophysical luminescent properties. We demonstrate that the Sparkle/PM3 model arises as a valid and efficient alternative to the simulation and prediction of the photoluminescent properties of lanthanide-organic frameworks when compared with methods traditionally used. Crystallographic investigations showed that the material is composed of neutral one-dimensional coordination polymers infinity(1)[Eu(DPA)(HDPA)(H(2)O)(2)] which are interconnected via a series of hydrogen bonding interactions involving the water molecules (both coordinated and located in the interstitial spaces of the structure). In particular, connections between bilayer arrangements of infinity(1)[Eu(DPA)(HDPA)(H(2)O)(2)] are assured by a centrosymmetric hexameric water cluster. The presence of this large number of O-H oscillators intensifies the vibronic coupling with water molecules and, as a consequence, increases the number of nonradiative decay pathways controlling the relaxation process, ultimately considerably reducing the quantum efficiency (eta = 12.7%). The intensity parameters (Omega(2), Omega(4), and Omega(6)) were first calculated by using both the X-ray and the Sparkle/PM3 structures and were then used to calculate the rates of energy transfer (W(ET)) and back-transfer (W(BT)). Intensity parameters were used to predict the radiative decay rate. The calculated quantum yield obtained from the X-ray and Sparkle/PM3 structures (both of about 12.5%) are in good agreement with the experimental value (12.0 +/- 5%). These results clearly attest for the efficacy of the theoretical models employed in all calculations and create open new interesting possibilities for the design in silico of novel and highly efficient lanthanide-organic frameworks.

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“…[ 56 ] Moreover, the shift of the NO stretching mode from 1254 cm −1 in the free bipyO 2 (Figure S1a, Supporting Information, wine line) to 1244 cm −1 in Eu(tta) 3 (bpyO 2 ) (Figure S1a, Supporting Information, red line), is assigned to the coordination of the Eu 3+ to the bipyO 2 ligand via the NO groups. [ 57 ] The weak band around 486 cm −1 is due to the formation of Ln 3+ O bonds (see arrow in Figure S1a, red line, Supporting Information). [ 58 ]…”

Section: Resultsmentioning

confidence: 99%

A Hybrid Materials Approach for Fabricating Efficient WLEDs Based on Di‐Ureasils Doped with Carbon Dots and a Europium Complex

Fang

Neto

et al. 2021

Adv Materials Technologies

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White light-emitting diodes (WLEDs) revolutionized the lighting industry providing high energy efficiency and a long lifetime. The recent development of efficient ultraviolet (UV) LEDs pushed forward the development of WLEDs based on mixtures of down-shifting phosphors and the current challenges are focused on the design of sustainable light converting materials with tunable correlated color temperature (CCT) and high color rendering index (CRI). Here we report a simple route to design sustainable WLEDs with tunable and enhanced color features through the assembly of a commercial LED chip (400 nm) and flexible films of a di-ureasil hybrid comprising a mixture of a cyan component originating from amorphous carbon dots and a red one resulting from the Eu(tta)3(bpyO2) (tta -: 2-thenoyltrifluoroacetonate and bpyO2: 2,2'-dipyridyl-1,1'-dioxide) complex. This red emission is responsible for high CRI arising from an unprecedented efficient energy bridge between bpyO2 and tta − excited states mediated by the hybrid host, as modeled by theoretical calculations based on the density functional theory and intramolecular energy transfer. WLED prototypes were fabricated with a tunable CCT from cold (5796 K) to warm (4228 K) white-light with high CRI values of 89 and 84, respectively, outperforming the state-of-the-art of UV-based WLEDs.Received: ((will be filled in by the editorial staff))Revised: ((will be filled in by the editorial staff))

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Synthesis, sparkle model and spectroscopic studies of the Eu(hfc)3·bipyO2 complex

Cited by 20 publications

References 24 publications

Modeling, Structural, and Spectroscopic Studies of Lanthanide-Organic Frameworks

Modeling, Structural, and Spectroscopic Studies of Lanthanide-Organic Frameworks

Theoretical and Experimental Studies of the Photoluminescent Properties of the Coordination Polymer [Eu(DPA)(HDPA)(H₂O)₂]·4H₂O

A Hybrid Materials Approach for Fabricating Efficient WLEDs Based on Di‐Ureasils Doped with Carbon Dots and a Europium Complex

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Synthesis, sparkle model and spectroscopic studies of the Eu(hfc)3·bipyO2 complex

Cited by 20 publications

References 24 publications

Modeling, Structural, and Spectroscopic Studies of Lanthanide-Organic Frameworks

Modeling, Structural, and Spectroscopic Studies of Lanthanide-Organic Frameworks

Theoretical and Experimental Studies of the Photoluminescent Properties of the Coordination Polymer [Eu(DPA)(HDPA)(H2O)2]·4H2O

A Hybrid Materials Approach for Fabricating Efficient WLEDs Based on Di‐Ureasils Doped with Carbon Dots and a Europium Complex

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Theoretical and Experimental Studies of the Photoluminescent Properties of the Coordination Polymer [Eu(DPA)(HDPA)(H₂O)₂]·4H₂O