Macromolecules, Vol.47, No.15, 4870-4875, 2014
Diamond Rings or Dumbbells: Controlling the Structure of Poly(ethylene glycol)-Fullerene [60] Adducts by Varying Linking Chain Length
Fullerene [60] (C-60) and poly(ethylene glycol) (PEG) adducts were prepared via 1,3-dipolar cycloaddition of bis-azido-terminated linear PEG (N-3-PEG-N-3) and C-60. While long chain length PEGs (M-n = 1000 and 3350 Da) yielded the cyclic diamond ring structures (subset of(C60)(PEG1000)superset of and subset of(C60)(PEG3350)superset of), short-chained PEG (M-n = 200 Da) yielded a telechelic dumbbell structure (C-60-PEG(200)-C-60). Both dumbbell and diamond ring structures were characterized by MALDI-TOF-MS, H-1 NMR, FTIR, UV-vis, and elemental analysis (EA). The results highlight the structural dependence of the PEG-C-60 adducts on the chain length of the azido-terminated polymer, a factor previously neglected.