title: Multiphoton-gated cycloreversion reactions of photochromic diarylethene derivatives with low reaction yields upon one-photon visible excitation.
abstract: Cycloreversion processes of three photochromic diarylethene derivatives with extremely low one-photon reaction yields (5.0 x 10(-5) to 1.5 x 10(-2)) were investigated by means of femtosecond and picosecond laser photolysis methods. Femtosecond visible laser photolysis revealed that the excited state of the closed form in these three derivatives decayed into the ground state with 0.7-8 ps time constants and with low cycloreversion yields that were consistent with those obtained by steady-state light irradiation. On the other hand, the cycloreversion reaction was drastically enhanced by picosecond 532 nm laser excitation for all of the three derivatives. From excitation intensity effects of the reaction yield and dynamic behavior, it was found that the successive two-photon absorption process leading to higher excited states opened an efficient cycloreversion channel, with reaction yields of 0.3-0.5. These results are discussed from the viewpoint of the one-photon inerasable but two-photon erasable photochromic system.
authors.affiliation: Division of Frontier Materials Science, Graduate School of Engineering Science, Center for Quantum Science and Technology under Extreme Conditions, Osaka University, Toyonaka, Osaka 560-8531, Japan.
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Ishibashi
authors.forename: Katsuki
authors.initials: K
authors.lastname: Okuno
authors.forename: Chikashi
authors.initials: C
authors.lastname: Ota
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Umesato
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Katayama
authors.forename: Masataka
authors.initials: M
authors.lastname: Murakami
authors.forename: Seiya
authors.initials: S
authors.lastname: Kobatake
authors.forename: Masahiro
authors.initials: M
authors.lastname: Irie
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Miyasaka