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 gamma-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, C-13 CP/MAS, and H-1 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.