Benzoylthiourea Derivative as a Dual-Mode Colorimetric and Fluorescent Chemosensor for Copper (II) Ion Detection

Chong, Kah Yan (2026) Benzoylthiourea Derivative as a Dual-Mode Colorimetric and Fluorescent Chemosensor for Copper (II) Ion Detection. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

In this study, N-(phenethylcarbamothioyl)benzamide (BT) was developed as a dual-mode colorimetric and fluorescent chemosensor and successfully synthesized through an acyl isothiocyanate route. BT was obtained with a melting point of 112.49 °C and its structure was verified using FTIR, ¹H NMR, ¹³C NMR, UV-Vis, and LC-MS. The FTIR spectrum showed characteristic absorption bands at 3397 cm-1 (N-H), 1670 cm-1 (C=O) and 1247 cm-1 (C=S), with noticeable shifts in the C=O and C=S stretching bands upon coordination with Cu2+, indicating their involvement in metal binding. The 1H NMR spectrum showed characteristic signals for CONH (11.321 ppm) and CSNH (10.943 ppm), along with aliphatic (2.969 – 3.857 ppm) and aromatic protons (7.234 – 7.916 ppm). The 13C NMR spectrum displayed peaks for C=S (180.67 ppm) and C=O (168.51 ppm), as well as aliphatic (33.97 – 46.71 ppm) and aromatic carbons (126.85–139.43 ppm), supporting the proposed structure. The molecular ion peak at 284.1 m/z corresponded to the protonated BT. UV-Vis analysis revealed two absorption peak at 280 nm (n →