Salicylaldehyde-5-aminosalicylic Acid Schiff Base and its Rare Earth Complexes:Synthesis,Characterization, and Bacteriostatic Activity

Salicylaldehyde-5-aminosalicylic acid Schiff base was obtained from salicylaldehyde and 5-amino-salicylic acid and Nd(Ⅲ), Gd(Ⅲ), and Yb(Ⅲ) complexes with it were synthesized. Elemental analysis, molar conductance, IR,1 H NMR, and TG-DTA measurements of the three rare earth complexes indicate that the Schiff base acts as a quadridentate ligand and the coordination numbers are 7 for Nd 3+ , and 9 for Gd3+ and Yb3+. The ligand and synthesized rare earth complexes show good bacteriostatic activities against staphyococcus aureus, escherichia cocli and withered grass bacillus. Moreover, the bacteriostatic activities of salicylaldehyde-5-aminosalicylic acid Schiff base and its Nd(Ⅲ) , Gd(Ⅲ) and Yb(Ⅲ ) complexes are related to the rare-earth elements themselves and increased with the increase of the concentrations of the Schiff base and its complexes.