Preparation of the complexes
A hot ethanolic solution (∼15 mL, 0.001 mol) of ligand was taken in a round bottom flask and heated for about 10 min at 70 °C to make the solution clear. Then hot ethanolic solution (∼15 mL, 0.001 mol) of the corresponding metal salt was added with continuous stirring and then refluxed for about 12–15 h. On cooling at room temperature, the solid product was precipitated out. The resulting solid product was filtered, washed several times with ethanol, and dried in vacuum over P4O10.