title: Control of the photoreactivity of diarylethene derivatives by quaternarization of the pyridylethynyl group.
abstract: Photochromic behavior of diarylethene derivatives with (4-pyridyl)ethynyl group directly attached to the 6-pi hexatriene moieties of the diarylethenes was investigated. Upon quaternarization of the pyridine moieties, the photoreactivity was strongly suppressed. On the other hand, diarylethene derivatives with nonconjugated (4-pyridyl)ethyl group exhibited the photochromic reactivity, regardless of whether pyridyl rings are quaternarized or not. In the case of the (4-pyridyl)ethynyl-substituted compounds, the photochromic reactivity was suppressed by the addition of trifluoroacetic acid and was restored by diethylamine.
authors.affiliation: Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Yumoto
authors.forename: Masahiro
authors.initials: M
authors.lastname: Irie
authors.forename: Kenji
authors.initials: K
authors.lastname: Matsuda