Molecular adducts between iodine and some benzazole-2-thione and -2-selone derivatives

Abstract

Spectrophotometric studies of adducts obtained by reacting molecular iodine and some benzazole-2-thione and -2-selone derivatives have been carried out in CH₂Cl₂ solutions. The thermodynamic and spectral characteristics of these complexes have been determined. Except for benzoxazole-2-selone and 3-methylbenzothiazole-2-selone, at least one isosbestic point has been found in the spectra of all the compounds, indicating the formation of a 1:1 molecular adduct. This model, employed for the calculation of the stability constants, fits the experimental data well in all cases. A non-linear least-squares method has been used for the calculation, and attention has been taken in selecting the experimental points to improve the reliability of the K and ε values.