Abstract
Here are reported the synthesis and characterization of four new dibenzo-24-crown-8 (DB24C8)-based ammonium-containing pseudorotaxanes, for which one of the two encircled axle's extremities consists of a perfluorobutyl moiety. The subsequent dethreading of the DB24C8 over the perfluorobutyl extremity was studied. Although the perfluorobutyl extremity of an ammonium-containing axle did not allow threading of DB24C8, dethreading of a perfluorobutyl extremity-containing pseudorotaxane was possible and its rate depended on both the strength of the template-to-DB24C8 complex and the nature of the axle. In particular, dethreading process may be assisted by the presence, in the threaded axle, of a poor secondary site of interaction for the DB24C8 and this assistance proved to be higher when this site is close to the DB24C8.