Synthesis, Characterization, and Antioxidant Activity of Thiosemicarbazide-Derived Schiff Base

Lee, Jay Kit Ming (2026) Synthesis, Characterization, and Antioxidant Activity of Thiosemicarbazide-Derived Schiff Base. Final Year Project (Bachelor), Tunku Abdul Rahman of Management and Technology.

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Abstract

Thiosemicarbazide (TSC) is an organosulfur compound with the molecular formula CH₅N₃S. It is structurally derived from semicarbazide, where the oxygen atom is replaced by a sulfur atom, leading to enhanced nucleophilicity and coordination ability (PubChem, 2025). The presence of three nitrogen atoms and a thiocarbonyl (-C=S) functional group makes thiosemicarbazide a versatile ligand in coordination chemistry and an important precursor in organic synthesis (Lasek et al., 2024). Its derivatives are widely used in organic synthesis to form various heterocyclic compounds. Due to the presence of multiple reactive centers, these compounds serve as excellent precursors for synthesizing nitrogen- and sulfur-containing heterocycles such as pyrazoles, pyrazolotriazines, pyrimidines, thiazoles, thiadiazines, thiadiazoles, triazines, and others (Acharya et al., 2021). Thiosemicarbazide consists of an amine (-NH₂), a hydrazine (-NH-NH₂), and a thiocarbonyl (-C=S) functional group, allowing it to engage in multiple types of chemical interactions, including hydrogen bonding, nucleophilic addition, and metal coordination. It also contains a great solubility toward water, ethanol and other polar organic solvents. Other than that, thiosemicarbazide reacts with aldehydes and ketones to form Schiff bases, specifically thiosemicarbazones, through a condensation reaction. This reaction occurs when the amine (-NH₂) group of thiosemicarbazide attacks the carbonyl (-C=O) group of the aldehyde or ketone (Adam et al., 2024). The presence of three nitrogen atoms and a thiocarbonyl (-C=S) functional group makes thiosemicarbazide a versatile ligand in coordination chemistry and an important precursor in organic synthesis (Hanganu et al., 2024).