Synthesis, Characterisation and Antioxidant Activity of Thiosemicarbazide Derived Schiff Base

Ng, Jing Shan (2026) Synthesis, Characterisation and Antioxidant Activity of Thiosemicarbazide Derived Schiff Base. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

In this study, a novel thiosemicarbazide-derived Schiff base, (E)-2-[(3- hydroxyphenyl)methylidene]-N-ethylhydrazine-1-carbothioamide (ETHBA), was synthesised using a reflux method. The ligand synthesised were characterized by Fourier Transform Infrared (FTIR) spectroscopy, melting point apparatus, Differential Scanning Calorimetry (DSC), Ultraviolet-Visible (UV-Vis) spectroscopy, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. Characterisation results indicated that ETHBA predominantly exists in the thione (C=S) tautomeric form in both the solid and solution states. The synthesised ligand was further evaluated for its antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and compared with its raw materials. The findings showed that ETHBA exhibited higher antioxidant activity than its raw materials.