Probing Intramolecular CH−π Interactions in o-Quinodimethane Adducts of [60]Fullerene Using Variable Temperature NMR
摘要:
Several o-quinodimethane adducts of [60]fullerene were synthesized and their intramolecular aryl CH-fullerene pi interactions were studied using variable temperature-NMR (VT-NMR). Evaluation of the rate constants associated with the first-order transition states for cyclohexene boat-to-boat inversions enables quantification of Delta G(double dagger) values for each inversion. A comparison between two constitutional isomers, only one of which is capable of intramolecular CH-pi interactions, provides a lower limit of 0.95 kcal/mol for each aryl CH-fullerene pi interaction.
Probing Intramolecular CH−π Interactions in o-Quinodimethane Adducts of [60]Fullerene Using Variable Temperature NMR
摘要:
Several o-quinodimethane adducts of [60]fullerene were synthesized and their intramolecular aryl CH-fullerene pi interactions were studied using variable temperature-NMR (VT-NMR). Evaluation of the rate constants associated with the first-order transition states for cyclohexene boat-to-boat inversions enables quantification of Delta G(double dagger) values for each inversion. A comparison between two constitutional isomers, only one of which is capable of intramolecular CH-pi interactions, provides a lower limit of 0.95 kcal/mol for each aryl CH-fullerene pi interaction.