Role of temperature on stability constants of metal complexes in 50% (V/V) water-ethanol solution.

Thermodynamic protonation constants of 5-aldehydosalicylic acid-aniline Schiff base, [5ASAA], and o-, m-, p-Toluidine Schiff bases with 5-aldehydosalicylic acid have been determined by Calvin –Bjerrum pH titration technique as used by Irving and Rossotti. The thermodynamic formation constants of the chelates of Cu (II), Co (II), Ni (II), Zn (II), Cd (II) and Mg (II) with these four ligands have been determined at four different temperatures in 50% (v/v) water-ethanol mixture; the stabilities of complexes follow the Irving-William’s order.