Fluorinated [2]rotaxanes with spirofluorene motifs: a non-symmetric distribution of the ring component along the axle component

Abstract

Oxidative dimerization of terminal alkynes (Glaser coupling) triggered by spirofluorene derived macrocyclic phenanthroline–Cu complexes was implemented to synthesize a series of novel [2]rotaxanes. Size and structural variations among the components and their implications on the dynamic behaviour were investigated in detail through ¹H and ¹⁹F NMR spectroscopy. Strong perturbations in the NMR spectra of the rotaxanes with substituted macrocyclic components with low symmetry indicated the non-symmetric distribution of the ring component along the axle component. In some [2]rotaxanes, localization of the ring component in the proximity of the 1,3-diyne moiety was observed.