Synthesis and characterization of spin-labelled rotaxanes containing tetrathiafulvalene and 1,5-dioxynaphthalene molecular stations†‡
The central component of one of the most studied programmable molecular switches reported by Stoddart and Heath is a rotaxane, which consists of a cyclobis(paraquat-p-phenylene) shuttle (CBPQT4+)(PF6−)4 (the ring) encircling a finger and moving between two molecular stations, tetrathiafulvalene (TTF) and 1,5-dioxynaphthalene (DNP). In order to employ ESR spectroscopy for understanding the mechanism of this switch, we report here the synthesis and characterization of rotaxanes having persistent nitroxide radicals as the stopper units and TTF or DNP as molecular stations. Isolation of the rotaxanes was successful when bulky nitroxide radicals containing cyclohexyl substituents at 2 and 6 positions of the piperidine-N-oxyl ring were used as terminal stoppers.
- This article is part of the themed collection: In Celebration of Max Malacria’s 65th Birthday