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 1H 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. A series of diacetylene‐containing crown ethers was synthesized in high yields by employing copper(II)‐mediated Eglinton coupling as the key macrocyclization. Complexation results show that macrocycles with tetraethylene glycol and triethylene glycol chains bind a paraquat guest to form [2]‐ and [3]pseudorotaxane‐like complexes, respectively.