THE STOICHIOMETRY AND STABILITY OF BETA-CYCLODEXTRIN COMPLEXES OF SOME AROMATIC KETONES AND THIOKETONES

Stoichiometry and stability constants of beta-cyclodextrin (beta-CD) c omplexes of several aromatic ketones and the corresponding thioketones were determined by the spectrophotometric and solubility methods. The solubility method with high-performance liquid chromatography (HPLC) detection of the solute concentration proved to be very convenient in determination of the stability constant for the least soluble thioketo ne. The formation constants were correlate with 1-octanol-water partit ion coefficients, which vary over more than five orders of magnitude f or compounds studied. The hydrophobic interaction and dispersion force s were found to be the most important sources of the complex stability . Relatively strong hydrogen bonds between the ketone molecules and wa ter destabilize their beta-cyclodextrin complexes. Stoichiometry of al l P-cyclodextrin complexes studied was found to be 1:1. The synthesis of a new alkyl derivative of 4H-1-benzopyran-4-one and 4H-1-benzopyran -4-thione was described.