Preparation and higher-order structures of 2,6-pyridylene and 2,6-pyrazylene alternating macrocycle with the inner nitrogen atoms in all the aromatic rings

Abstract

A shape-persistent macrocycle (SPM) consisted of three 2,6-pyridylene and three 2,6-pyrazylene rings alternately linked with acetylene bonds was prepared by Sonogashira reactions. X-ray crystallography revealed the planar macrocyclic structure, and intermolecular π-stacking was observed at the sides of the hexagon. An AFM measurement of the sample prepared by drop-casting on a mica substrate showed a reticulate fibril.