Gas-Solution Phase Transient Absorption Study of the Plant Sunscreen Derivative Methyl Sinapate
Gas-Solution Phase Transient Absorption Study of the Plant Sunscreen Derivative Methyl Sinapate
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DOI：
10.1002/cptc.201800060
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发表时间：
2018-08-01
期刊：
影响因子：
3.7
通讯作者：
Stavros, Vasilios G.
中科院分区：
文献类型：
--
作者：
Baker, Lewis A.;Staniforth, Michael;Stavros, Vasilios G.
植物防晒衍生物新加坡酸甲酯的气相和液相研究是了解苹果酸新加坡酯等植物防晒剂结构-动力学-功能关系的重要一步。气相实验结果表明，光激发后存在三步失活过程。光激发到S-1态导致内部振动能量在3ps内重新分布。然后在S-1和T-1之间发生30ps的系统间交叉，然后后者状态持续到我们的探测窗口之外（>> 1ns）。在弱扰动溶剂环己烷的溶液中，观察到光物理性质的显著变化。通过11* /S-0的锥形交叉，观察到在3ps中发生了反顺异构化。未完成异构化的居群在9ps内通过振动能量转移到溶剂而松弛。然后观察到长寿命的光产物持续存在，并确定为顺式异构体。
The plant sunscreen derivative methyl sinapate is studied in the gas- and solution-phase as an important step in understanding the structure-dynamics-function relationship of plant sunscreens such as sinapoyl malate. Results from gas-phase experiments suggest a three step deactivation process after photoexcitation. Photoexcitation to the S-1 state results in internal vibrational energy redistribution within 3ps. Intersystem crossing then occurs in 30ps between S-1 and T-1 and the latter state then persists outside our probe window (>> 1ns). In solution with the weakly perturbing solvent cyclohexane, a dramatic change in the photophysical properties is observed. A trans-cis isomerisation is observed to occur in 3ps via a 11* /S-0 conical intersection. The population which does not complete the isomerisation, relaxes via vibrational energy transfer to the solvent in 9ps. A long-lived photoproduct is then observed to persist and is identified as the cis-isomer.