Efficient Syntheses and Complexation Studies of Diacetylene‐Containing Macrocyclic Polyethers

A series of novel macrocyclic polyethers, phenylene–diacetylene‐containing macrocycles was synthesized in high yields by employing copper(II)‐mediated Eglinton coupling as the key macrocyclization (80–92 %). As an analogue of the bisphenylene crown ether hosts, the binding behavior of these new macrocycles was investigated by 1 H NMR spectroscopy, mass spectrometry (ESI), and X‐ray crystallography. The results obtained indicate that macrocycles with tetraethylene glycol chains ( 3c – e ) bind a paraquat guest to form [2]pseudorotaxane‐like complexes in solution and in the solid state, whereas macrocycles with triethylene glycol chains (i.e., 3f – h ) bind a paraquat guest to form [3]pseudorotaxane‐like complexes, which implies that macrocycles 3f – h may be able to complex to (mono)pyridinium cations in a [2]pseudorotaxane‐like fashion in solution.