Enthalpimetric titration of copper chelates with some adduct-forming ligands

Abstract

Thermodynamic functions and stability constants for 1:1 adduct formation of bis-(thenoyltrifluoroacetonato) copper(II) and bis-(benzoyltrifluoroacetonato) copper(II) with pyridine, 1,10-phenanthroline, 2,2′-bipyridyl, 4-methylpyridine N-oxide, tributylphosphate, trioctylphosphineoxide and dibenzylsulphoxide have been obtained in benzene at 35°C by direct titration calorimetry. The enthalpy changes (Δ H) are exothermic while the entropy changes (Δ S) are unfavourable for all the reactions studied. The values of Δ H and K have been correlated with the nature of the ligands (i.e., basicity, structure, etc.) wherever possible.