Synthesis, Structures, and Complexation with Phenolic Guests of Acridone‐Incorporated Arylene–Ethynylene Macrocyclic Compounds

Abstract

Acridone units were incorporated into the aryleneethynylene structure as polar arene units. Cyclic trimers consisting of three acridone-2,7-diyl units and three 1,3phenylene units were synthesized by Sonogashira couplings via stepwise or direct route. X-ray analysis revealed that the trimer had a nearly planar macrocyclic framework with a cavity surrounded by three carbonyl groups. In contrast, the corresponding tetramer had a nonplanar macrocyclic framework. 1 H NMR measurements showed that the trimer formed a 1 : 1 complex as a macrocyclic host with dihydric phenol guests, and the association constants were determined to be ca. 1.0 × 10 3 L mol À 1 for hydroquinone or resorcinol guests in CDCl 3 at 298 K. The calculated structures of these complexes by the DFT method supported the presence of two sets of OH•••O=C hydrogen bonds between the host and guest molecules. The spectroscopic data of the cyclic trimers and tetramers are compared with those of reference acridone compounds.