Abstract

Thymol (Thy) is a widely known anti-microbial agent and can be found as one of the components of many essential oils. Intermolecular charge-transfer complexes between the Thy as a donor and picric acid (PA), chloranilic acid (CLA), 1,3 dinitrobenzene (DNB) or pchloranil (p-CHL) as a -acceptor have been structurally and thermally studied in methanol at room temperature. Based on elemental
analyses (CHN) and photometric titrations, the stoichiometry of the complexes (Thy: acceptor molar ratios) was determined to be 1:1 for all four complexes. The formation constant (KCT), molar extinction coefficient (CT) and other spectroscopic data have been determined using the Benesi–Hildebrand method and its modifications. The newly synthesized CT complexes have been characterized via elemental analyses (CHN), IR, 1H-NMR, and electronic absorption spectroscopy. Thermogravimetric analyses (TG) were also used to investigate the thermal stability of the synthesized solid CT complexes.

Key words: Thymol, Charge-transfer, Benesi–Hildebrand method, Thermal analysis