Abstract
Adduct formation between α-, β-, γ-, and (permethyl)γ-cyclodextrins (CDs) on the one hand and 1,6-diphenyl-1,3,5-hexatriene (DPH) on the other was studied by fluorescence spectroscopy in a DMF/water mixed solvent. The four complexes, CD−DPH, were found to exhibit remarkable differences in their structures. Thus, while the α- and β-homologues form 1/1 complexes with DPH, γ-homologue forms nanotubes involving ca. 30 cyclodextrin units and an unknown number of DPH molecules. If, however, the hydrogens of all the OH groups in the γ-cyclodextrin are replaced by CH3 groups, nanotubes do not form. Also, when the alkalinity of an aqueous solution, in which γ-CD and DPH have formed nanotubes, is increased above pH = 12, the nanotubes break down. Moreover, nanotube formation does not occur also when DPH is replaced by certain of its derivatives, very similar to it in structure and rodlike in shape.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have