Synthesis of macrocyclic polyethers via Ru complex-catalyzed metathesis cyclization and their use as the ring component of rotaxanes

Ring closing metathesis of the vinyl group-terminated oligoethers catalyzed by RuCl2(CHPh)(PCy3)2 yielded macrocyclic polyethers containing vinylene group. The obtained 23-membered cyclic ether reacted with benzyl(anthrylmethl)ammonium hexafluorophosphate to produce the pseudo-rotaxane as colorless crystals. X-ray crystallography revealed N-H⋯O hydrogen bonds and stacking of the aromatic planes between the host and guest molecules, which stabilized the rotaxane structure in the solid state. The 1H NMR spectra of the solutions containing the macrocyclic polyether and several secondary ammonium salts indicated the formation of pseudo-[2]-rotaxanes.