عنوان

سنتز و شناسایی کمپلکس های هیدرازونی جدید محلول در آب و بررسی فعالیت آنتی اکسیدانی آن ها

Abstract: In this research work, at first (PL2) named 3-(3-formyl-4-hydroxybenzyl)-1-methyl-1H-Imidazol-3-ium chloride was synthesized as a preligand compound. Then new water-soluble Schiff base ligands were synthesized by condensation reaction of acetyl hydrazide and semicarbazide hydrochloride with PL2 to produce H2L1Cl and H2L2Cl, respectively, and were characterized by spectroscopic methods (UV-Vis، FT-IR ،1HNMR). According to the FT-IR spectra, appearance of the peak related to imine (C=N) bonds in 1624 cm-1(H2L1Cl) and 1648 cm-1(H2L2Cl), also, disappearing of the aldehyde group peaks confirm the formation of a Schiff base ligands. In addition, presence of the absortion bond related to C=O group (1678 cm-1 for H2L2Cl and 1699 cm-1 for H2L1Cl) confirms that ligands remain in its ketonic form in solid state. Furthermor 1HNMR results confirm that the ligands remain in their ketonic form in solution. Reaction of the ligands with copper(II) and zinc(II) chlorides under reflux conditions in methanol produced expected complexes that were characterized by spectroscopic methods (UV-Vis، FT- IR and 1HNMR ) .In FT-IR spectra of complexes shift of carbonyl group wavelength showed coordination of this group but in ketonic form. Also, according to the 1HNMR results protons of OH group in zinc complexes are not found in the spectra, which confirms the coordination of phenolic oxygen to zinc metal after deprotonation. Antioxidant activity of the compounds was measured by Bluis method and was measured and compared with ascorbic acid as a standard. Antioxidant avtivity of compounds were evaluated for their scavenging activity against picrylhydrazyl radical (DPPH). According to the the results, H2L1Cl(IC50>1000ppm) exhibit much less antioxidant avtivity than Cu(HL1) (IC50 = 83.28) and Zn(HL1) (IC50 = 25.25). Also Zn(HL2)(IC50= 225./6) exhibit more antioxidant avtivity than H2L2Cl (IC50 = 139.52) and Cu(HL2)( IC50 = 196.15).