A direct luminescence spectroscopic experimental setup for the determination of complex stability constants of mononuclear uranyl(VI) hydrolysis species is presented. The occurrence of polynuclear species is prevented by using a low uranyl(VI) concentration of 10–8 M (2.4 ppb). Time-resolved laser-induced fluorescence spectra were recorded in the pH range from 3 to 10.5. Deconvolution with parallel factor analysis (PARAFAC) resulted in three hydrolysis complexes. A tentative assignment was based on thermodynamic calculations: UO22+, UO2(OH)+, UO2(OH)2, UO2(OH)3–. An implementation of a Newton–Raphson algorithm into PARAFAC allowed a direct extraction of complex stability constants during deconvolution yielding log(β1M,1°C)1:1 = −4.6, log(β1M,1°C)1:2 = −12.2, log(β1M,1°C)1:3 = −22.3. Extrapolation to standard conditions gave log(β0)1:1 = −3.9, log(β0)1:2 = −10.9, and log(β0)1:3 = −20.7. Luminescence characteristics (band position, lifetime) of the individual mononuclear hydroxo species were derived to serve as a reference data set for further investigations. A correlation of luminescence spectroscopic features with Raman frequencies was demonstrated for the mononuclear uranyl(VI) hydroxo complexes for the first time. Thereby a signal-to-structure correlation was achieved and the complex assignment validated.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/acs.analchem.5b03958 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Main-Group Metals Stabilized Polypyrrolic Uranyl(V) Complexes via Cation-Cation Interaction with the Uranyl -Oxo Atom: A Relativistic Density Functional Theory Study.
Inorg Chem
December 2020
Key Laboratory of Functional Inorganic Material Chemistry, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, China.
To explore the innovative uranyl(V) complexes by deeply understanding their coordination stability, relativistic density functional theory calculations have been performed to investigate the experimentally reported [(py)(RAlOUO)(py)(HL)] [R = Me (), Bu ()] and [{(py)MOUO}(py)(HL)] [M = Li (), Na (), K ()] and their uranyl(VI) counterparts. Structural and topological analyses along with transformation-reaction energies and redox potentials were systematically studied. Geometrical and quantum theory of atoms in molecules analyses implied a linear U-O-M feature in - and a bent one in and .
View Article and Find Full Text PDFAdsorption of U(VI) on Stoichiometric and Oxidised Mackinawite: a DFT Study.
Environ Sci Technol
June 2020
Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, U.K.
Naturally occurring minerals, such as the iron sulfide mackinawite, play a key role in the remediation of uranium from groundwater systems. Here, density functional theory (DFT) is used to investigate the interaction of uranium with the most stable surface of stoichiometric mackinawite, {001}-S. The high reactivity of the mineral toward oxygen may affect its ability to sequester uranium; therefore, two models of oxidized mackinawite are also used to study the effect of surface oxidation on adsorption.
View Article and Find Full Text PDFStructural elucidation and physicochemical properties of mononuclear Uranyl(VI) complexes incorporating dianionic units.
Sci Rep
September 2016
School of Chemistry, Bharathidasan University, Tiruchirappalli-620024, Tamil Nadu, India.
Two derivatives of organouranyl mononuclear complexes [UO2(L)THF] (1) and [UO2(L)Alc] (2), where L = (2,2'-(1E,1'E)-(2,2-dimethylpropane-1,3-dyl)bis(azanylylidene, THF = Tetrahydrofuran, Alc = Alcohol), have been prepared. These complexes have been determined by elemental analyses, single crystal X-ray crystallography and various spectroscopic studies. Moreover, the structure of these complexes have also been studied by DFT and time dependent DFT measurements showing that both the complexes have distorted pentagonal bipyramidal environment around uranyl ion.
View Article and Find Full Text PDFSpeciation Studies of Metals in Trace Concentrations: The Mononuclear Uranyl(VI) Hydroxo Complexes.
Anal Chem
April 2016
Institute of Resource Ecology, and ‡Helmholtz Institute Freiberg for Resource Technology, Helmholtz-Zentrum Dresden-Rossendorf , Dresden, 01328 Saxony, Germany.
A direct luminescence spectroscopic experimental setup for the determination of complex stability constants of mononuclear uranyl(VI) hydrolysis species is presented. The occurrence of polynuclear species is prevented by using a low uranyl(VI) concentration of 10–8 M (2.4 ppb).
View Article and Find Full Text PDFTheoretical investigation on the mechanism and dynamics of oxo exchange of neptunyl(VI) hydroxide in aqueous solution.
Phys Chem Chem Phys
March 2015
CAS Key Laboratory of Nuclear Radiation and Nuclear Energy Techniques, and Multidisciplinary Initiative Center, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
Four types of reaction mechanisms for the oxo ligand exchange of monomeric and dimeric neptunyl(VI) hydroxide in aqueous solution were explored computationally using density functional theory (DFT) and ab initio classical molecular dynamics. The obtained results were compared with previous studies on the oxo exchange of uranyl hydroxide, as well as with experiments. It is found that the stable T-shaped [NpO3(OH)3](3-) intermediate is a key species for oxo exchange in the proton transfer in mononuclear Path I and binuclear Path IV, similar to the case of uranyl(VI) hydroxide.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!