title: Photochemical reaction of p-hydroxycinnamic-thiophenyl ester in the microcrystalline state.
abstract: We have studied the photochromic reaction of p-hydroxycinnamic-thiophenyl ester in the microcrystalline state. We attributed the fluorescence spectral evolution of the microcrystal, under UV irradiation, to the photoinduced trans-to-cis isomerization. The photocyclic behavior of the chromophore was demonstrated by cis-to-trans back reaction under a subsequent visible light irradiation. In addition, the [2 + 2] topochemical photocyclodimer was observed as another photoproduct. It is considered that the cooperative photoisomerization is initiated at the local lattice distortion and free spaces around the [2 + 2] cyclodimer near the crystal surface, and the photoisomerization induces larger lattice deformation and further photoisomerization in the interior of the crystal.
authors.affiliation: Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan. usman@faculty.nctu.edu.tw
authors.forename: Anwar
authors.initials: A
authors.lastname: Usman
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Asahi
authors.forename: Teruki
authors.initials: T
authors.lastname: Sugiyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Masuhara
authors.forename: Norimitsu
authors.initials: N
authors.lastname: Tohnai
authors.forename: Mikiji
authors.initials: M
authors.lastname: Miyata