Spark-Source Mass Spectrometric Techniques for the Analysis of Lanthanide and Actinide Elements in Microgram and Sub-Microgram Transuranium Samples

Abstract

Lanthanide and actinide impurities in a total sample of 1 to 10 μg of transuranic matrix can be determined by employing the spark-source mass spectrograph and solution technique. A special source glove box permits safe manipulation of transuranium elements with α-emitting radioactivity up to 10¹² dpm. The minimum detection limit is about 10¹² atoms per electrode system and an exposure of 10^?8 coulomb. Relative sensitivity values for the lanthanides and actinides were established with respect to erbium, the internal standard.     

Density functional studies of AnF6 (An=U,Np, and Pu) and UF6−nCln (n=1–6) using hybrid functionals: geometries and vibrational frequencies

We have compared the performance of widely used hybrid functionals for calculating the bond lengths and harmonic vibrational frequencies of AnF₆ (An=U, Np, and Pu) and UF_6?nCl_n (n=1–6) molecules using “small‐core” relativistic effective core potentials and extended basis sets. The calculated spectroscopic constants compare favorably with experimental data for the bond lengths (average error ≤ 0.01 Å) and vibrational frequencies (average error ≤ 7 cm^?1) of the AnF₆ molecules. The experimental vibrational frequencies of the stretching modes were available for most of the UF_6?nCl_n (n=1–6) molecules. The calculated vibrational frequencies are in good agreement with the experimental data to within 4.6 cm^?1 and 7.6 cm^?1 for selected Becke1 and Lee, Yang, Parr (B1LYP), and Becke3 and Perdew, Wang (B3PW91) functionals, respectively. We conclude that one can predict reliable geometries and vibrational frequencies for the unknown related systems using hybrid density functional calculations with the RECPs. The geometries and vibrational frequencies of the UF_6?nCl_n (n=1–6) molecules that have not been determined experimentally are also presented and discussed. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 2010–2017, 2001     

Photochemistry of f-element ions

Published data on photochemical reactions of f-element compounds, namely, uranyl ion and lanthanide and actinide ions, are surveyed and analyzed. The types of reactions of photoexcited ions, reaction mechanisms, and analytical applications of the photochemical methods for the separation, isolation, and determination of f-elements are considered.     

Metal-Carboxyl Helical Chain Secondary Units Supported Ion-Exchangeable Anionic Uranyl–Organic Framework

As a less explored avenue, actinide-based metal-organic frameworks (MOFs) are worth studying for the particularity of actinide nodes in coordination behaviour and assembly modes. In this work, an azobenzenetetracarboxylate-based anionic MOF supported by uranyl–carboxyl helical chain units was synthesized, incorporating linear uranyl as the metal centre. This kind of helical chain-type building unit is reported for the first time in uranyl-based MOFs. Structural analysis reveals that the formation of helical chain secondary units can be attributed to restricted equatorial coordination of rigid flat azobenzene ligand to uranyl centres. Meanwhile, this newly-synthesized anionic material has been used to remove Eu³⁺ ions, as a non-radioactive surrogate of Am³⁺ ion, through an ion-exchange process with [(CH₃)₂NH₂]⁺ ions in its open channels, as evidenced by a combination of ¹H NMR spectroscopy, EDS and PXRD.     

Rare-Earth-compound nanowires, nanotubes, and fullerene-like nanoparticles: synthesis, characterization, and properties

Various low-dimensional nanostructures, such as nanowires, nanotubes, nanosheets, and fullerene-like nanoparticles have been selectively synthesized from rare-earth compounds (hydroxides, fluorides) based on a facile hydrothermal method. The subsequent dehydration, sulfidation, and fluoridation processes lead to the formation of rare-earth oxide, oxysulfide, and oxyhalide nanostructures, which can be functionalized further by doping with other rare-earth ions or by coating with metal nanoparticles. Owing to the interesting combination of novel nanostructures and functional compounds, these nanostructures can be expected to bring new opportunities in the vast research areas of and application in biology, catalysts, and optoelectronic devices.     

Mono and bis[N-aryl(benzyl)]amides of phosphorylacetic acids. One-pot synthesis and extraction of actinides from nitric acid solutions

A one-pot synthetic route to phosphorylacetic acid N-aryl(alkylaryl)amides, including those containing two phosphorylmethylcarbamoyl moieties attached to the arene framework, has been developed. The method is based on reactions of amines with the corresponding acid chlorides generated in situ with the use of phosphorus trichloride as a mild chlorinating agent. The compositions and structures of the compounds obtained and their extraction ability toward Am^III were determined. Suggestions were made about the compositions of the extracted complexes with phosphorylacetic acid N-aryl(alkylaryl)amides. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1387–1394, August, 2006.