Charge-transfer complexes formed between 1-hydroxybenzotriazole versus iodine and picric acid electron acceptors: electronic, infrared and morphological characterizations

A charge-transfer process between an electron-rich and an electron-deficient component creates molecular assemblies, which have several uses in a variety of electronic, optical, sensor, and catalysis fields. Therefore, this study was focused on getting some knowledge about the intermolecular charge transfer complexes between the 1-hydroxybenzotriazole (HBT) with picric acid (PA) and iodine (I2) as π and σ­ acceptors. The charge-transfer interaction of the HBT electron donor and the PA acceptor has been studied in methanol solvent. The resulting data referred to the formation of the new CT-complex with the general formula [(HBT)(PA)]. The 1:1 stoichiometry of the reaction was discussed upon the on elemental analysis and photometric titration. On the other hand, the 1:1 HBT-iodine (I2) charge-transfer complex has been studied spectrophotometrically in chloroform at room temperature with general formula [(HBT)(I2)]. The electronic absorption bands of (I2) are observed at ~ 510 nm. Raman laser spectrum of the brown solid iodine complex has two clear vibration bands at 165 and 113 cm-1 due to I2 stretching frequency, respectively. The scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) of two HBT charge-transfer complexes were discussed. KEY WORDS: Benzotriazole, Charge transfer, Electron acceptors, Spectroscopic, Morphology Bull. Chem. Soc. Ethiop. 2025, 39(7), 1437-1450. DOI: https://dx.doi.org/10.4314/bcse.v39i7.15