Synthesis And Properties Of Gallic Acid Esters' Complexes With Metals(Zn, Zr)

In this paper, the methyl gallate-Zr(MG-Zr), propyl gallate-Zn(PG-Zn) and propyl gallate-Zr(PG-Zr)complexes were synthesized and characterized, for the more, the anti-bacteria effect of PG-Zn were approached.Three new complexes were synthesized in water solution using transition metals(Zr, Zn)and gallic acid esters, including methyl gallate and propyl gallate. Three complexes were characterized by UV-Vis,IR,far IR,1H-NMR and TG-DTA spectra. The result shows that methyl gallate or propyl gallate ligands with Zr, Zn atoms through the phenolic hydroxyl. The UV-Vis spectrum of complexes and ligands are different. The UV-Vis region of each complex is wider and makes red shift when compared with its ligand. The mid-infrared spectra of between each complex and its ligand shows that the phenolic hydroxyl broad band change and the stretching vibration peaks of benzene ring shift. In the far-infrared absorption spectra of complexes, some peaks at 320-480 cm-1 are assigned to the stretching frequency of M-O. The 1H-NMR spectra of propyl gallate and propyl gallate-Zn in DMSO-d6 suggest that the coordinate bond formation takes place through the phenolic hydroxyl groups and water.The anti-bacteria function of propyl gallate-Zn was approached via continuously dilution method. The results show that the higher concentrations of propyl gallate-Zn, the better anti-bacteria function of propyl gallate-Zn, and the anti-bacteria function to gram-positive bacteria is better to gram-negative bacteria.