Absorption spectra of 4f electron transitions of neodymium and erbium complexes with ferron and diethylamine. Determination of neodymium and erbium in rare earth mixtures by third-derivative spectrophotometry

Wang, Nai‐Xing; Liang, Weian; Zhou, Shi-Fu; Qi, Ping

doi:10.1016/0003-2670(92)80062-c

Cited by 12 publications

(1 citation statement)

References 3 publications

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“…For example, according to reports of the lanthanide series published by Carnall et al, the location of the absorption bands for the studied lanthanide ions is in accordance with the location of the energy levels of each ion. Furthermore, based on experimental data of molecules in which a similar coordination environment exists for the lanthanide centers, similar transitions have been obtained in correct agreement with the results of this work. − Finally, in spite of the lack of experimental information about these specific fragments, the accurate results obtained employing the same methodology on other lanthanide systems support the robustness of the calculations. ,,, …”

Section: Resultssupporting

confidence: 84%

Theoretical Determination of Energy Transfer Processes and Influence of Symmetry in Lanthanide(III) Complexes: Methodological Considerations

2018

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This work presents a theoretical protocol to analyze the symmetry effect on the allowed character of the transitions and to estimate the probability of energy transfer in lanthanide(III) complexes. For this purpose, a complete study was performed based on the multireference CASSCF/PT2 technique along with TDDFT, to build the energy level diagrams and determine the spectral overlap integrals, respectively. This approach was applied on a series of LnIII complexes, viz. [LnCl(DMF)(Dpq)]/[Ln(NO)(DMF)(Dpq)], where Ln = Sm, Tb, Er/Eu, Nd and dpq = dipyridoquinoxaline, synthesized and characterized by Patra et al. ( Dalton Trans. 2015 , 44 ( 46 ), 19844 - 19855 ; CrystEngComm 2016 , 18 ( 23 ), 4313 - 4322 ; Inorg. Chim. Acta 2016 , 451 , 73 - 81 ). A fragmentation scheme was applied where both the ligand and the lanthanide fragments were treated separately but at the same level of theory. The symmetry analysis only partially reproduced the expected results, and a more detailed analysis of the crystal field became necessary. On the other hand, the most probable energy transfer pathways that take place in the complexes were elucidated from the energy gaps between the ligand-localized triplet state and the emitting levels of the lanthanide fragments. These gaps, which are related to the energy transfer rate, properly reproduced the trend reported experimentally for the best and worst yields. Finally, the spectral overlap integral was calculated from the emission spectra of the dpq ligand and the absorption spectra of the lanthanide fragment. The obtained values are in good agreement with the quantum yields calculated for the systems. The most remarkable aspect of this protocol was its ability to explain the emission and nonemission of the studied compounds.

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Section: Resultssupporting

confidence: 84%

Theoretical Determination of Energy Transfer Processes and Influence of Symmetry in Lanthanide(III) Complexes: Methodological Considerations

2018

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A study of riboflavin determination by square wave adsorptive stripping voltammetry on mercury film electrodes

Economou¹,

Fielden²

1995

Electroanalysis

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In this work riboflavin was determined by square wave adsorptive stripping voltammetry (SWASV): riboflavin was initially adsorbed on a mercury film electrode (MFE) at a potential of 0.0 V (vs. Ag/AgCl) and at pH 12; the subsequent reductive stripping step was carried out by applying a square wave potential-time waveform on the electrode. Both a batch method (based on the rotating disk electrode configuration) and a flow approach [based on the wall-jet flow-through electrode and flow injection analysis (FIA)] were employed. Both instrumental and chemical parameters were investigated and optimized for analytical use of the technique. The limit of detection was 0.5 nmol L-' (for 10 min of preconcentration), the precision was 8 % for the batch system (at the 10nmolL-' level) and 6% for the flow system (at the 100nmol L-' level); the linear range depended on the preconcentration time and the mass transfer conditions during the accumulation step. Both methods were automated and applied to the determination of riboflavin in commercial pharmaceutical products with recovery values at over 90%.

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Derivative spectrophotometric determination of neodymium in rare earth mixtures using bromopyrogallol red and TX-100

Wang

Liu

1994

Fresenius J Anal Chem

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Absorption spectra of 4f electron transitions of neodymium and erbium complexes with ferron and diethylamine. Determination of neodymium and erbium in rare earth mixtures by third-derivative spectrophotometry

Cited by 12 publications

References 3 publications

Theoretical Determination of Energy Transfer Processes and Influence of Symmetry in Lanthanide(III) Complexes: Methodological Considerations

Theoretical Determination of Energy Transfer Processes and Influence of Symmetry in Lanthanide(III) Complexes: Methodological Considerations

A study of riboflavin determination by square wave adsorptive stripping voltammetry on mercury film electrodes

Derivative spectrophotometric determination of neodymium in rare earth mixtures using bromopyrogallol red and TX-100

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