Reversible conversion of electronic structures in a cyclic octacopper complex

A study was conducted to present a a cyclic sulfur-bridged octacopper complex that undergoes interconversion between its neutral, monocationic, and dicationic species. It was observed that the monocationic and dicationic species exhibit characteristic and intense absorption in the near-infrared (NIR) region, which is a significant property for applications involving telecommunications and optical data storage. It was demonstrated that the reaction of 2-(dimethylaminophenyl)benzothiazoline with copper(II) acetate monohydrate in a ratio 2:1 in 1,2-dichloroethane under a nitrogen atmosphere gave a black solution from which a dark brown powder ([1]-[CuCl₂]) was isolated by adding diethyl ether. It was also demonstrated that the dicationic and monocationic species possess radicals that are delocalized over the Cu₈S₈ core and show a intense absorption band in the NIR region.