COMPLEXATION OF La(III) METAL ION WITH NOVEL SCHIFF BASES: THERMODYNAMIC STUDY

Abstract

In the present work we have investigated the stability constant of seven Schiff bases with trivalent rare earth metal ion Lanthanum using a pH metric titration technique in 80% (v/v) ethanol-water mixture at three different temperatures 298K, 308K 8 318K at an ionic strength of 0.1M NaClO4. The Calvin-Bjerrum method as adopted by Irving-Rossotti has been employed to determine metal-ligand stability constant logK values. The thermodynamic parameters such as, Gibb’s free energy change (ΔG), entropy change (ΔS) and enthalpy change (ΔH) associated with the complexation reactions were calculated.