Preparation and spectroscopic studies on charge-transfer complexes of 2-hydroxypyridine with electron acceptors

• Spectroscopic investigations on the interaction of 2-hydroxypyridine as an electron donor with σ- and π-acceptors.
• σ- and π-acceptors used in this study are iodine, chloranilic acid and 2,3-dichloro-5,6-dicyano-p-benzoquinone.
• The prepared CT-complexes have the general formula [(HPyO)(acceptor)].
• Formation constant, charge transfer energy and thermal analyses data of CT-complexes are presented.

The CT-interactions of electron acceptors such as iodine (I2), chloranilic acid (H2CA) and 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) with 2-hydroxypyridine (HPyO) have been investigated in the defined solvent. The data indicate the formation of CT-complexes with the general formula [(HPyO)(acceptor)]. The 1:1 stoichiometry of the (HPyO)–acceptors were based on elemental analysis, IR spectra and thermogravimetric analysis of the solid CT-complexes along with the photometric titration measurements for the reactions. The formation constants (KCT) for the CT-complexes are shown to be strongly dependent on the type and structure of the electron acceptors. Factors affecting the CT-processes are discussed.