Photochemical reaction of p-hydroxycinnamic-thiophenyl ester in the microcrystalline state.
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.
Usman
Anwar
A
Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan. usman@faculty.nctu.edu.tw
Asahi
Tsuyoshi
T
Sugiyama
Teruki
T
Masuhara
Hiroshi
H
Tohnai
Norimitsu
N
Miyata
Mikiji
M