Organogel formation by a cholesterol-stoppered bistable rotaxane and its dumbbell precursor
Stoddart, J. Fraser
Date of Issue2008
School of Physical and Mathematical Sciences
The switching properties, gelation behavior, and self-organization of a cholesterol-stoppered bistable rotaxane containing a cyclobis(paraquat-p-phenylene) ring and tetrathiafulvalene/1,5-dioxynaphthalene recognition units situated in the rod portion of the dumbbell component have been investigated by electrochemical, spectroscopic, and microscopic means. The cyclobis(paraquat-p-phenylene) ring in the rotaxane can be switched between the tetrathiafulvalene and 1,5-dioxynaphthalene recognition units by addressing the redox properties of the tetrathiafulvalene unit. The organogels can be prepared by dissolving the rotaxane and its dumbbell precursor in a CH2Cl2/MeOH (3:2) mixed solvent and liquified by adding the oxidant Fe(ClO4)3. Direct evidence for the self-organization was obtained from AFM investigations which have shown that both of the rotaxane and its dumbbell precursor form linear superstructures which we propose are helical in nature.
Journal of the American chemical society
© 2008 American Chemical Society