Complexation Thermodynamics of Selenacrown Ether: Origin of High Silver(I) Selectivity of 1,5,14,18-Tetraselena-8,11,21,24- tetraoxacyclohexacosane

Abstract

The thermodynamic parameters and relative cation selectivity for complexation of some alkali and heavy metal cations with 1,5,14,18-tetraselena-8,11,21,24-tetraoxacyclohexacosane (selena-26-crown-8) are investigated for the first time by titration calorimetry in water–acetonitrile (1:24 v/v) at 25°C to show the contrasting complexation thermodynamic behaviour between Ag⁺ and alkali or Tl⁺ and a very high Ag⁺ selectivity, originating from the exclusive contribution of the enthalpy term probably owing to the partially covalent interaction between Ag⁺ and Se donor.