Study of the complexation reactions between substituted 1,10-phenanthroline-2,9-dicarboxamide and lanthanide nitrates
Actinides and lanthanides are by-products of nuclear fuel production. The process of their extraction consists of several stages and includes the separation of actinides and lanthanides. Due to the very similar chemical properties for group separation, we needed complexing agents showing appropriate selectivity. Phenanthrolinedicarboxylic acid amides are promising new reagents used to separate f-elements. In this work, we have studied the reaction of complexation of heavy lanthanides (Tb3+-Lu3+) with 4,7-dichloro-N,N'-diphenyl-1,10-phenanthroline-2,9-dicarboxamide in acetonitrile.
We determined the composition and values of the stability constants of the complexes by spectrophotometric titration on a Hitachi U1900 spectrophotometer. The composition of the complex was determined by method of continuous variations and the titrimetric method. The compositions of complexes for all studied metal-ligand pairs were one-to-one. The results were processed using the HypSpec2014 program. All complexes studied were highly stable (lgβ>6). The dependence of the ionic radius of a metal is represented by a bell-shaped curve on the holmium ion.
Authors thank the RSF (project No. 16-13-10451) for financial support.
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Faculty of Chemistry, Lomonosov Moscow State University
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