Redox-Active Hydrocarbons: Isolation and Structural Determination of Cationic States toward Advanced Response Systems

Organic chemistry has developed rapidly as a carbon-based science. Particularly, hydrocarbons with aromatic rings have attracted much attention as molecular materials for use in organic electronics. In principle, aromatic species can be constructed if carbon and hydrogen atoms are available. Therefore, revealing the nature of pure hydrocarbons with an (anti)aromatic nature should pave the way for the development of as yet unexplored organic materials. In this Review, we focus on pure hydrocarbons composed of only carbon and hydrogen atoms, and present recent studies on their intrinsic electrochemical and spectroscopic properties and structural characterization of their cationic states. We also address more sophisticated hydrocarbon-based response systems that are capable of modulating their properties in response to external stimuli such as light, heat, and electric potential.