HOST GUEST CHEMISTRY .26. NMR AND FLUORESCENCE STUDIES OF CYCLODEXTRIN COMPLEXES WITH GUEST MOLECULES CONTAINING BOTH PHENYL AND NAPHTHYL UNITS

The complexation constants of alpha-, beta-, and gamma-cyclodextrin (alpha-, beta-, gamma-CD's) with 1-anilino-8-naphthalensulfonate (ANS) and 2-toluidino-6-naphthalenesulfonate (TNS) are (re)evaluated on the basis of different complex and computational models based particularly on NMR titrations. The NMR shifts exerted by the CD's on protons of the guest molecules together with intermolecular NOE's taken from 2D-ROESY spectra give insight into the modes of intracavity inclusion in aqueous solution. In contrast to expectations based on the cavity width alpha-CD binds phenyl moieties only weakly, whereas beta-CD and gamma-CD show more or equal intracavity immersion of the smaller phenyl than of the larger naphthalene residues.