Self-assembly behavior of phenyl modified β-cyclodextrins

The self-assembly behavior of mono(6-phenolic-6-deoxy)-β-cyclodextrin (1) both in solution and the solid state is comparatively studied by X-ray crystallography and ¹H NMR spectroscopy. The results obtained show that the phenolic groups in the crystal 1 can successively penetrate into the adjacent β-cyclodextrin cavities from the secondary side to form head-to-tail linear polymeric supramolecule with a 2-fold screw axis. The self-assembly behavior also can be determined in D₂O solution, giving a self-association constant of 240 mol⁻¹·L. Using the present and previous structures reported for the relevant β-cyclodextrin derivatives, i.e., mono(6-anilino-6-deoxy)-β-cyclodextrin (2), mono(6-phenylselenyl-6-deoxy)-β-cyclodextrin (3), and mono(6-phenylthio-6-deoxy)-β-cyclodextrin (4), we further reveal the factors governing the formations of supramolecular assemblies.