Chemistry of Anthracene–Acetylene Oligomers. XVIII. Construction and Structures of Belt-Shaped Macrocyclic Oligomers with Anthracene Units and Acetylene Linkers and Resolution of Chiral Derivatives

Abstract

Abstract Acyclic anthracene–acetylene trimers consisting of two 1,8-anthrylene units and one 1,5- or 1,8-anthrylene unit were cyclized by Eglinton coupling to form the corresponding cyclic trimer, hexamer, and higher oligomers. The molecular structures of these oligomers were investigated by X-ray analysis and DFT calculations at the M05/3-21G level. The trimers have rigid macrocyclic frameworks and the hexamer and higher oligomers prefer to take flat or folded structures due to transannular π···π interactions between the anthracene units. Cyclic hexamers and higher oligomers feature chiral structures that are likened to figure-eight or directional belts. The enantiomers of some chiral cyclic oligomers were resolved by chiral HPLC. The dynamic behavior of the macrocyclic frameworks and each anthrylene unit was observed by variable-temperature 1H NMR measurements. The electronic spectra of these cyclic oligomers are discussed in terms of ring size and the combination of anthrylene units.