Spectroscopic Studies of Lanthanides Ion in High-Temperature Molten Salt

Song, Kyuseok; Yeon, Jei‐Won

doi:10.1080/05704928.2015.1054498

Cited by 6 publications

(3 citation statements)

References 59 publications

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“…Hypersensitive f-f-transition 4 I 15/2 → 4 G 11/2 of erbium(III) was located at almost the same wavelength (379 nm). [23] Thus, 4f-luminescence observed under excitation at 371 nm was a result of both intramolecular transfer from phthalocyanine and in a less degree from porphyrin chromophores and direct excitation of Er(III) ion. So, this "three-component" 4f-luminescence had a value of 8450 a.u.…”

Section: Uv-vis Spectrum Of Heteroleptic Double-decker Complex [(15c5mentioning

confidence: 97%

Infrared 4f-Luminescence of Erbium(III) Complexes with Tetrapyrrole Ligands

Semenishyn¹,

Smola²,

Русакова³

et al. 2018

MHC

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The luminescent properties of the series of erbium(III) complexes of various coordination types with different tetrapyrrole macrocycles (porphyrins, phthalocyanines and corroles) are discussed in this paper. The investigated series of compounds include mononuclear porphyrinato complexes (metal-ligand ratio 1:1, tppEr(acac)), sandwich phthalocyaninato-porphyrinato type complexes (metal-ligand ratio 1:2 [(15C5) 4 Pc]Er[(4-BrC 6 H 4) 4 Por] or 2:3-(Pc) Er[(15C5) 4 Pc]Er(Pc) and [(15C5) 4 Pc]Er[(15C5) 4 Pc]Er(Pc)), ditopic porphyrins and corroles possessing peripheral lanthanides binding (metal-ligand ratio 1:1, Er-edta-H 2 atpp•2H 2 O, Er-Hdtpa-H 2 atpp, Er-edta-H 3 dpfc•2H 2 O and Er-Hdtpa-H 3 dpfc). 4f-Luminescence in the near-infrared region is observed in all studied Er-complexes as a result of intramolecular transfer of excitation energy. The unique features of each type of complexes are discussed in details. The peripheral complexes are dual-emissive: they display both erbium(III) 4f-emission in near-infrared and molecular fluorescence in the visible spectral region. The values of quantum yield of molecular fluorescence as well as the intensity of 4f-luminescence are estimated. It was found that the binding type of erbium(III) plays a key role in the macrocycle excited state relaxation. The doubledecker heteroleptic complex [(15C5) 4 Pc]Er[(4-BrPh) 4 Por] possesses unusual emission behaviour.

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Section: Uv-vis Spectrum Of Heteroleptic Double-decker Complex [(15c5mentioning

confidence: 97%

Infrared 4f-Luminescence of Erbium(III) Complexes with Tetrapyrrole Ligands

Semenishyn¹,

Smola²,

Русакова³

et al. 2018

MHC

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“…In molten chloride salts, lanthanides such as Nd, Eu, Ce, and Ho are observed to exist predominantly in their Ln(III) oxidation state and form octahedrally coordinated LnCl 6 3– anionic complexes as measured by spectrophotometric techniques. − The octahedral coordination complex has also been demonstrated in a variety of RTIL systems such as in the chloroaluminate melt and a variety of chloride-doped hydrophobic RTILs. − Electrochemical investigations of lanthanides exhibiting an accessible Ln(III/II) couple also reveal fast, reversible electron transfer characteristics through cyclic voltammetry (CV) and suggest that electron transfer is dominated by outer-sphere effects. , Further, they demonstrate that the Cl – ligand has a strong stabilizing effect on the Ln III oxidation states and is reflected as a negative shift in their reduction potentials . These influences of the salt electrolyte environment were corroborated by MacInnes et al who found that the molten salt cation polarization strength played a significant role in the stability of lanthanide chloride anionic complexes due to outer-sphere coordination effects .…”

Section: Introductionmentioning

confidence: 99%

Room-Temperature Ionic Liquid Cation Effects on the Structure and Stability of Anionic Lanthanide Complexes

Unger

Jensen

2023

Inorg. Chem.

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Room-temperature ionic liquids (RTILs) are a subset of molten salts that are liquids at room temperature and may offer an elegant, low-temperature route to predicting the properties of solvated metal complexes in their high-temperature analogues. This work studied the chemistry of chloride anion-containing RTILs to determine their similarity to inorganic molten chloride salts. The behaviors of complexes of Mn, Nd, and Eu were evaluated in a variety of chloride RTILs by absorption spectrophotometry and electrochemistry to elucidate trends in cation effects on the coordination geometry and redox properties of the solvated species. Spectrophotometric data indicated the metals are present as anionic complex (e.g., MnCl 42− and NdCl 6 3−) analogous to those observed in molten chloride salts. Strongly polarizing, charge-dense RTIL cations induced distortions to the symmetry of these complexes, resulting in lower oscillator strengths and red-shifted energies for the observed transitions. Cyclic voltammetry experiments were used to characterize the Eu(III/II) redox couple producing diffusion coefficients on the order of 10 −8 cm 2 s −1 and heterogeneous electron transfer rate constants ranging between 6 × 10 −5 and 2 × 10 −4 cm s −1 . The E 1/2 potentials for Eu(III/II) were also found to shift positively with increasing cation polarization power, stabilizing the Eu(II) oxidation state by removing electron density from the metal center over chloride bond networks. Both the optical spectrophotometry and electrochemistry results suggest that the polarization strength of an RTIL cation plays a major role in the geometry and stability of a metal complex.

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“…3,6 Several mechanisms for redox control have been developed 3 and molten salt samples can be retrieved from the reactors in order to provide chemical characterization with electrochemical and spectroscopic methods. [7][8][9] In situ chemical analysis can be realized through X-ray absorption spectroscopy and the determination of thermophysical properties through laser flash analysis and high-temperature calorimetry. 6 As a wide range of vapors, salt mists, pyrolysis products, and aerosols may be generated during the operation of an MSR, 8 our research has been focused on the development of methods for the generation and chemical identification of off-gassed products under simulated MSR conditions.…”

Section: Introductionmentioning

confidence: 99%

Detection of Off-Gassed Products From Molten Salts Using Laser-Induced Breakdown Spectroscopy

Díaz

Hahn

2023

Appl Spectrosc

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The detection of off-gassed sodium from molten sodium nitrate (NaNO3) at temperatures between 330 °C and 505 °C and off-gassed calcium from molten lithium chloride–potassium chloride eutectic (LKE) mixtures at 510 °C with laser-induced breakdown spectroscopy (LIBS) was demonstrated. NaNO3 and LKE samples were melted in a custom-built crucible that promoted the generation of off-gassed products from the molten sample. The off-gassed products were analyzed with a LIBS system designed to probe the high-temperature environment. Na D emission lines, Na(I)588.99 nm and Na(I) 589.59 nm, were detected from the NaNO3 samples after reaching a temperature threshold, which indicated the occurrence of phase change. In LKE mixtures, the detection of Ca impurities at a concentration of 78 mg/kg was possible using the emission lines Ca(II) 393.66 nm and Ca(II) 395.85 nm. This work demonstrates the real-time monitoring capabilities of LIBS in high-temperature environments that simulate the conditions of molten salt reactors.

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Spectroscopic Studies of Lanthanides Ion in High-Temperature Molten Salt

Cited by 6 publications

References 59 publications

Infrared 4f-Luminescence of Erbium(III) Complexes with Tetrapyrrole Ligands

Infrared 4f-Luminescence of Erbium(III) Complexes with Tetrapyrrole Ligands

Room-Temperature Ionic Liquid Cation Effects on the Structure and Stability of Anionic Lanthanide Complexes

Detection of Off-Gassed Products From Molten Salts Using Laser-Induced Breakdown Spectroscopy

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