Chemistry of Anthracene–Acetylene Oligomers. XIII. Synthesis, Structures, and Spectroscopic Properties of All Possible 1,8-Anthrylene Cyclic Tetramers with Acetylene and Diacetylene Linkers

Abstract

Abstract All the possible 1,8-anthrylene cyclic tetramers with acetylene and diacetylene linkers were synthesized as new types of π-conjugated compounds. Building units were connected by coupling reactions, and macrocyclization of the tetrameric precursors by Eglinton coupling gave the desired cyclic oligomers. Molecular structures examined by X-ray analysis and DFT calculations with the M05 functional revealed diamond prism structures with intramolecular contacts between facing anthracenes at ca. 3.5 Å. Restricted dynamic processes between the diamond forms were observed by VT 1H NMR measurements of the cyclic tetramer with one diacetylene linker and the Cs symmetric isomer with two diacetylene linkers. The enantiomers of three chiral cyclic tetramers were resolved by spontaneous resolution or chiral HPLC, and their chiroptical properties were investigated by CD spectroscopy. Absorption and emission spectra and NMR chemical shifts of these oligomers are discussed in terms of the molecular structures.