Aqueous Complexation of Y^III, La^III, Nd^III, Sm^III, Eu^III, and Yb^III with Some Heterocyclic Substituted β‐Diketones

Abstract

Abstract This paper deals with spectrophotometric investigation on complexation of Y III , La III , Nd III , Sm III , Eu III , and Yb III metal ions with six heterocyclic substituted β‐diketones. The stability constants of 36 monocomplex species was determined in aqueous solutions at 298 K and I = 0.25; it lay in the range from 5.14 to 9.76 logarithmic units. The influence of the natures of the metal and ligand on the stability constant along with the dependence of the stability constant on an ionic potential ( z / r ) was studied and is discussed. The acid–base, tautomeric, and dimeric equilibriums of the studied substituted β‐diketones have been investigated using UV/Vis and 1 H NMR spectroscopy. Also, ab initio calculations of electronic structures of metal aquacomplex species, anions of β‐diketones, and their complex species have been carried out.