Stable and unconventional conformation of single PEG bent γ-CD-based polypseudorotaxanes

The unexpected formation of polypseudorotaxanes via attaching 2-bromoisobutyryl groups to both ends of poly(ethylene glycol) (PEG), which leads to the self-assembly with γ-cyclodextrins in aqueous solution, is reported in this study. The resulting polypseudorotaxanes exhibit stable and unconventional single PEG bent conformations as evident from XRD, FTIR, GPC, ¹³C CP/MAS, and ¹H NMR analyses. These polypseudorotaxane products are so stable that they can initiate the bulk ATRP of butyl methacrylate to give rise to the same conformational polypseudorotaxanes. The formation of novel polypseudorotaxanes is reported via attaching a 2-bromoisobutyryl group to both ends of PEG and then self-assembling with γ-cyclodextrins in aqueous solution. The resulting polypseudorotaxanes exhibit stable and unconventional single PEG bent conformations. Furthermore, they can initiate the bulk ATRP of butyl methacrylate to give the same conformational polypseudorotaxanes.