Bull James N, Carrascosa Eduardo, Mallo Neil, Scholz Michael S, da Silva Gabriel, Beves Jonathon E, Bieske Evan J
School of Chemistry, University of Melbourne , Parkville, Victoria 3010, Australia.
School of Chemistry, UNSW Sydney , High Street, Kensington, New South Wales 2052, Australia.
J Phys Chem Lett. 2018 Feb 1;9(3):665-671. doi: 10.1021/acs.jpclett.7b03402. Epub 2018 Jan 24.
Donor-acceptor Stenhouse adducts (DASAs) are a new class of photoswitching molecules with excellent fatigue resistance and synthetic tunability. Here, tandem ion mobility mass spectrometry coupled with laser excitation is used to characterize the photocyclization reaction of isolated, charge-tagged DASA molecules over the 450-580 nm range. The experimental maximum response at 530 nm agrees with multireference perturbation theory calculations for the S ← S transition maximum at 533 nm. Photocyclization in the gas phase involves absorption of at least two photons; the first photon induces Z-E isomerization from the linear isomer to metastable intermediate isomers, while the second photon drives another E-Z isomerization and 4π-electrocyclization reaction. Cyclization is thermally reversible in the gas phase with collisional excitation.
给体-受体斯滕豪斯加合物（DASAs）是一类新型的光开关分子，具有出色的抗疲劳性和合成可调性。在此，串联离子迁移率质谱联用激光激发用于表征在450-580nm范围内分离的、带有电荷标签的DASA分子的光环化反应。530nm处的实验最大响应与533nm处S←S跃迁最大值的多参考微扰理论计算结果相符。气相中的光环化涉及至少两个光子的吸收；第一个光子诱导从线性异构体到亚稳中间体异构体的Z-E异构化，而第二个光子驱动另一个E-Z异构化和4π-电环化反应。在气相中，环化在碰撞激发下是热可逆的。
