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Slow Intermolecular Complexation–Decomplexation Exchanges of Cyclodextrins in Fullerene and Its Derivative Complexes
Author(s) -
Ikeda Atsushi,
Mae Tomoya,
Sugikawa Kouta,
Komaguchi Kenji,
Konishi Toshifumi,
Hirao Takehiro,
Haino Takeharu
Publication year - 2017
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201702319
Subject(s) - intermolecular force , chemistry , steric effects , derivative (finance) , fullerene , substituent , dissociation (chemistry) , reaction rate constant , medicinal chemistry , computational chemistry , stereochemistry , organic chemistry , kinetics , molecule , physics , quantum mechanics , financial economics , economics
Fullerenes (C 60 and C 70 ) and several functionalized C 60 derivatives can be encapsulated in two γ‐cyclodextrins (γ‐CDxs). Although intermolecular complexation–decomplexation exchange of γ‐CDx is known to be very slow, the exchange rates have yet to be quantitatively measured. Herein, we determined that the pseudo‐first‐order association and dissociation rate constants for the γ‐CDx 2 •C 70 complex were 4.3 and 0.6 s −1 at 23 °C, respectively. In contrast, the intermolecular exchange rates for the γ‐CDx 2 •C 60 and C 60 derivative complexes were slower than the time scale of exchange spectroscopy NMR experiments and the exchange rate constants were in the order of 10 −4 s −1 . Furthermore, a γ‐CDx 2 •C 60 derivative complex was shown to have different intermolecular exchange rates for the two γ‐CDxs depending on steric hindrance from the substituent on the C 60 derivative.