A new thermo- and photo-driven [2]rotaxane

A new rotaxane with functional chromophores porphyrin and fluorene as stoppers has been synthesized. It displays dual fluorescent character. The macrocycle ring can shuttle between the fumaramide part and the succinimide part on the dumbbell. Heating and UV light irradiating on the rotaxane lead to the reversible E/Z conversion, driving the ring to shuttle between the two stations. The optical properties of porphyrin and fluorene stoppers of the thread do not change so much while the ring shuttles because the macrocycle does not interact with the two stoppers. However, the active group, propargyloxyl, is introduced onto the two sides of the ring so that the rotaxane has the potential to be functionalized by further decoration.