Bis(corannulenyl)ethene as an efficient photochromic material†

Abstract

We herein report photochromic 1,2-bis(2-methoxy-corannulenyl)perfluorocyclopentene (1) possessing two corannulene moieties as the side aryl units of diarylethene. One enantiomer and the other enantiomer of one chiral atropisomer of 1 respectively forming columnar structures in the crystal were revealed via single-crystal X-ray analysis. Compound 1 exhibited an efficient photochromic behaviour with a large molar absorption coefficient of 5.0 × 10⁴ M⁻¹ cm⁻¹, and significantly high photochemical quantum yields of 0.64 and 0.49 were demonstrated for photocyclization and photocycloreversion reactions, respectively. This high efficiency was rationalized by the changed abundance ratios of atropisomers between the open- and closed-isomers and the shortened distance between reactive carbons with the help of the curved structure. In addition, the application possibility of 1 as a photochromic material was demonstrated in a poly(methyl methacrylate) film.