Study of the substitution effect and solvation effect on the trans → cis photoisomerization of cinnamate derivatives

摘要

Cinnamic acid derivatives exhibit trans (E) → cis (Z) photo-isomerization after UV irradiation. In this study, we investigated the mechanism of nonradiative decay (NRD) process involving the photo-isomerization of methylcinnamate (MC, Fig.1) and its methanol complex under jet-cooled gas phase condition. We applied several spectroscopic measurements;; laser induced fluorescence (LIF) and two-color resonant-2-photon ionization (2C-R2PI) for the UV spectroscopy and lifetime measurement of the excited state. The transient state appeared during NRD was detected by UV-DUV spectroscopy. In parallel, the photo-isomerization route was searched by global reaction route mapping with TD-DFT calculation.