Competing Crystallization between Lanthanide and Actinide in Acidic Solution Leading to Their Efficient Separation

We present a new method for generating europium oxalate compounds by decomposing of N‐methyl 2‐pyrrolidone in HNO₃ media. The reaction exhibits high selectivity towards Eu³⁺ over UO₂²⁺, which suggests that these conditions could be applied to a selective crystallization based separation system for trivalent lanthanides and hexavalent actinides.     

Convenient synthesis of multifunctional EDTA-based chiral metal chelates substituted with an S-mesylcysteine

We describe the synthetic route to ethylenediaminetetraacetic acid (EDTA) derivatives that can be attached to surface-exposed thiol functional groups of cysteine residues in proteins, via a methylthiosulfonate moiety that is connected in a stereochemically unique way to the C-1 carbon atom of EDTA. Such compounds can be used to align proteins in solution without the need to add liquid crystalline media, and are, therefore, of great interest for the NMR spectroscopic analysis of biomolecules. The binding constant for the paramagnetic tag to lanthanide ions was determined by measuring luminescence. For the Tb(+3)-ligand complex, a K(b) value of 6.5 x 10(17) M(-1) was obtained. This value is in excellent agreement with literature values for the related EDTA compound. In addition, it could be shown that there is no significant reduction in the luminescence intensity upon addition of a 10(4) excess of Ca2+ ions, indicating that this paramagnetic tag is compatible with buffers containing high concentrations of divalent alkaline earth ions.     

Luminescent probing of the Tb-C bond in a catalyst of diene polymerization based on ThCl3 · 3(BunO)3PO+Bui 3Al

The application of chemiluminescence and photoluminescence methods is shown to be promising for studying the mechanism of diene polymerization on Ziegler-Natta catalysts based on organolanthan ide and organoaluminum compounds.The authors are grateful to N. V. Duvakina and Yu. B. Monakov for polymerization of several samples.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 2011–2015, August, 1996.