STRUCTURAL AND THERMAL INVESTIGATIONS OF NOVEL CHARGE-TRANSFER COMPLEXES OF THYMOL AND THE ACCEPTORS PICRIC ACID, CHLORANILIC ACID, 1,3-DINITROBENZENE AND r-CHLORANIL

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 p -chloranil ( p -CHL) as a p-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 (K CT ), molar extinction coefficient (e 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, 1 H-NMR, and electronic absorption spectroscopy. Thermogravimetric analyses (TG) were also used to investigate the thermal stability of the synthesized solid CT complexes.