Five amino acid Schiff bases: Sal-Gly (glycine acid Schiff base), Sal-Glu (glutamic acid Schiff base), Sal-Met (methionine acid Schiff base), Sal-Tyr (tyrosine acid Schiff base), Sal-Arg (arginine acid Schiff base), and its zinc complexes were synthesized and characterized by elemental analysis, ¹H NMR, IR and UV-vis techniques. The association behavior between Sal-Tyr-Zn and the nitrogen-containing compounds including imidazole (1), 1-methyl imidazole (2), 2-ethyl-4-methyl-imidazole (3), pyrazole (4), 4-iodoaniline (5), DABCO (1,4-diazobycyclo[2,2,2]octane) (6), 1,2-diaminobenzene (7) and 1,2-diaminocyclohexane (8) was studied. Amino acid Schiff bases and their zinc complexes have antibacterial activity to some fungus, so the antibacterial activity of the compounds to Escherichia coli was studied. The results show that both the amino acid Schiff base and their zinc complexes have the bacteriostatic activity to Escherichia coli. The antibacterial activity of the ligands decreased when the size of amino-acid residue R-group increased. The activity of the zinc complexes is more powerful than that of the ligands, and Sal-Arg-Zn shows the strongest inhibitory activity.

Key words: amino acid Schiff base, synthesis, characterization, antibacterial activity