UV SPECTROSCOPIC STUDY OF THE INTERACTION BETWEEN ALPHA-CYCLODEXTRIN, BETA-CYCLODEXTRIN, AND GAMMA-CYCLODEXTRIN AND PYRIDINE-DERIVATIVES

Complex formation between alpha-, beta- and gamma-cyclodextrins and some pyridine derivatives (hydroxy, O- and N-methyl) have been investigated by UV spectroscopy. Inclusion processes do not exert any noticeable influence on the UV absorption spectra of most of the guests which do not give rise to tautomeric equilibria or which show a strong prevalence for one of the tautomeric forms. In contrast, the equilibrium between the lactim and the lactim forms of 3-hydroxypyridine (which are present in comparable amounts in aqueous solution) was shown to be markedly affected by the inclusion process with a preferential complexation of the latter tautomer.