Tetrabenzoperipentacene: Stable Five-Electron Donating Ability and a Discrete Triple-Layered β-Graphite Form in the Solid State

An oxidative ring-closure reaction of a tetranaphthylpyrene derivative led to the synthesis of a 56 all-carbon conjugated tetrabenzoperipentacene. In the single-crystal X-ray structure, three molecules make a triple-layered cluster by π-stacking, wherein each layer rotates by 120°, and is thus considered a petit β-graphite. As for the optical properties, the Stokes shift is extremely small (10 cm(-1) ), thus indicating its remarkably rigid framework. The tetrabenzoperipentacene exhibits reversible five-electron oxidation waves in cyclic voltammetry, and is regarded as a counterpart to the fullerene C60 in terms of stable multicharge-storage nanocarbon materials.