title: Photochromic radical compounds based on a naphthopyran system.
abstract: [reaction: see text] Naphthopyran derivatives with aminoxyl substituents (4a,b) gave the corresponding open-formed isomers (5a,b) by irradiation, which could be changed back to the starting closed-formed naphthopyrans by the treatment with SiO(2) as a catalyst. The tuning of intermolecular magnetic interactions between the isomer couples was found to be possible in these reversible systems.
authors.affiliation: Department of Material Science, Graduate School of Science, Himeji Institute of Technology, 3-2-1 Kouto, Kamigori, Hyogo 678-1297, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kaneko
authors.forename: Hiroki
authors.initials: H
authors.lastname: Akutsu
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Yamada
authors.forename: Shin'ichi
authors.initials: S
authors.lastname: Nakatsuji