ИСТИНА

Phosphorus-based N-heterocycles are relevant ligands for luminescent complexes and as extractants for the chemical separation of f-elements. Measurements of thermodynamic functions are necessary elements for understanding the intramolecular processes occurring in complexation reactions. One of the thermodynamic parameters is the stability constant of complexes, which is an important characteristic of the behavior of the ligand in the process of complexation and how strong these complexes are. In this work, we will study the stability constants of europium complexes with a new type of phosphorus-containing ligands. We will determine the stability constant of complexes by spectrophotometric titration on a Hitachi - U1900 spectrophotometer. We will study the equilibrium system in “dry” acetonitrile (at a water content of 40 ppm): [Ln] + [L] ↔ [LnL]. Complex stoichiometry will be determined by the Job’s plot and titrimetry. We will establish the number of complex particles in the equilibrium system and the composition of complex. The stability constants of complexes (logβ1) will be calculated using the HypSpec2014 program. Authors thanks the RFBR (project No. 18-33-00626\18) for financial support of the synthesis of the organic phosphine sulfides and RSF (project No. ‪16-13-10451‬) for financial support of phosphine oxides preparation and spectral investigations represented here.