Synthesis, Characterization and Antioxidant Studies of Schiff Base Derived from Zingerone and 4-Phenyl-3-thiosemicarbazide and Its Metal Complex

Tan, Yong Ye (2023) Synthesis, Characterization and Antioxidant Studies of Schiff Base Derived from Zingerone and 4-Phenyl-3-thiosemicarbazide and Its Metal Complex. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Thiosemicarbazone (TSCs) is an organosulphur compound that is a class of Schiff bases that is widely used to study numerous biological activities due to its vast applications in binding to metal ions and biological applications. In this final year project, the Schiff base was synthesized by the condensation reaction of zingerone and 4-phenyl-3-thiosemicarbazide in a molar ratio of 1:1. The Schiff base was named (Z)-2-(4(4-hydroxy-5-methoxycyclohexa-1,3-dien-1-yl) butan-2-ylidene)-N-phenylhydrazine-1-carbothioamide and abbreviated as PTVA. The metal complex was then synthesized using zinc (II) metal salt and the ligand in a molar ratio of 1:2 and was abbreviated as Zn(PTVA)2. Both PTVA and Zn(PTVA)2 were characterized using numerous methods such as Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet-visible spectrophotometry (UV-Vis), Proton Nuclear Magnetic Resonance (1H NMR), Carbon Nuclear Magnetic Resonance (13C NMR), Flame Atomic Absorption Spectroscopy (FAAS), CHNS/O Elemental Analyzer (CHNS/O), and molar conductance analysis. The synthesized Zn(PTVA)2 was found to exist in thiol tautomer (C-SH) in the solid state whereas PTVA found to exist as thione tautomer (C=S) in both solid and liquid states. The antioxidant potency of both synthesized ligand and its metal complexes were evaluated by DPPH radical scavenging activity. The result shows that both PTVA and Zn(PTVA)2 possessed weak antioxidant potency than ascorbic acid such that PTVA works approximately 50% of antioxidant power of ascorbic acid whereas Zn(PTVA)2 works approximately 25% of antioxidant power of ascorbic acid