Chemically Responsive Supramolecular Assemblies of Pyrene-β-Cyclodextrin Dimer

We report supramolecular assemblies of a beta-cyclodextrin dimer linked at both ends of a fluorescent phenylethynylpyrene moiety (Py-beta-CD dimer). The Py-beta-CD dimer formed supramolecular associations in aqueous media due to the pi-pi stacking of the hydrophobic phenylethynylpyrene moiety. From tapping mode atomic force microscopy measurements, the Py-beta-CD dimer Formed wire-shaped assemblies in aqueous media. By adding sodium adamantane carboxylate to the supramolecular assemblies. the structural change to J-type assemblies was observed. In contrast, upon addition of the electron-deficient guest, the electron transfer from the electron rich Phenylethynylpyrene moiety of the supramolecular assemblies to the electron-deficient guest, took place.