A TRLFS Study on the Complexation of Cm^III and Eu^III with 2,6‐Bis(5,6‐dipropyl‐1,2,4‐triazin‐3‐yl)pyridine in Water/Methanol Mixture

Abstract

Abstract The complexation of Cm III and Eu III with 2,6‐bis(5,6‐dipropyl‐1,2,4‐triazin‐3‐yl)pyridine ( n Pr‐BTP) in water/methanol solution is studied. 1:3 complexes [M( n Pr‐BTP) 3 ] 3+ form from the solvated metal ions upon addition of ligand. The conditional stability constants are log K = 14.4 and log K = 11.9. For both metal ions the complexation reaction is both enthalpy and entropy driven. Δ H is 10.1 kJ/mol more negative than Δ H , whereas the entropy difference is small. The difference in Δ G between the formation of the Cm III and Eu III complexes is in good agreement with n Pr‐BTP's selectivity in liquid‐liquid extraction.