Studies on the nanotubes formed by 2-phenyl-5-(4-diphenylyl)1,3,4-oxadiazole and cyclodextrins

We report herein the interaction of 2-phenyl-5-(4-diphenylyl)1,3,4-oxadiazole (PBD) with α-, β-, and γ-cyclodextrins (CDs). It was found that the reaction patterns between PBD and CDs are remarkably different. α-CD can form a simple 1:2 (guest:host) inclusion complex with PBD, while β-CD and γ-CD can form nanotube with PBD at higher concentration of both PBD and CDs. It was also found that the interaction pattern of butyl-2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (butyl-PBD) with CDs is similar to that of PBD with CDs. On the basis of the above results, possible structures of these cyclodextrin nanotubes were discussed.