Comparison of association constants of cyclodextrins and their tert-butyl derivatives with halogenbenzoic acids and acridine derivatives.

Association constants of complexes of a new class of cyclodextrin alkyl der ivatives - randomly substituted tert-butyl derivatives (TB-CDs) with comple te set of mono-halobenzoic acids and acridine derivatives were measured usi ng capillary electrophoresis and compared with association constants of nat ural cyclodextrins. In most cases the association constants of natural cycl odextrin and its corresponding tert-butyl derivative were comparable. Stron g dependence of association constants on actual cyclodextrin concentration was observed for complexes of tert-butyl-alpha -cyclodextrin with acridine derivatives. Significant increase of the association constant occurred belo w the critical micelle concentration of the cyclodextrin derivative, while an increase above this value was less significant.