Direct Observation of Hydrogen Tunneling Dynamics in Photoexcited Phenol
Direct Observation of Hydrogen Tunneling Dynamics in Photoexcited Phenol
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DOI：
10.1021/jz2016318
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发表时间：
2012-02-02
影响因子：
5.7
通讯作者：
Stavros, Vasilios G.
中科院分区：
文献类型：
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作者：
Roberts, Gareth M.;Chatterley, Adam S.;Stavros, Vasilios G.
近年来，紫外线（UV）照射后苯酚的激发态动力学受到了相当大的关注，最值得注意的是，因为它们可以提供一个模型，用于了解紫外线诱导的芳香族氨基酸酪氨酸的动力学。尽管如此，当UV激发发生在（1）π π */（1）π sigma* 圆锥交叉点（CI）以下时，关于氢隧穿动力学是否在苯酚的激发态O-H键裂变中起重要作用，存在一些争论。在这封信中，我们提出了直接的证据，表明（1）π σ * 介导的O-H键裂变低于（1）π π */（1）π σ * CI完全通过氢隧道动力学进行。氢隧穿的观察可能有一些类似的质子隧穿动力学从酪氨酸残基（沿着的酚部分的O-H键）在广泛的天然酶，潜在地增加了进一步的理由利用酚作为模型系统研究酪氨酸为基础的动力学。
The excited-state dynamics of phenol following ultraviolet (UV) irradiation have received considerable interest in recent years, most notably because they can provide a model for understanding the UV-induced dynamics of the aromatic amino acid tyrosine. Despite this, there has been some debate as to whether hydrogen tunneling dynamics play a significant role in phenol's excited-state O-H bond fission when UV excitation occurs below the (1)pi pi*/(1)pi sigma* conical intersection (CI). In this Letter, we present direct evidence that (1)pi sigma*-mediated O-H bond fission below the (1)pi pi*/(1)pi sigma* CI proceeds exclusively through hydrogen tunneling dynamics. The observation of hydrogen tunneling may have some parallels with proton tunneling dynamics from tyrosine residues (along the O-H bond of the phenol moiety) in a wide range of natural enzymes, potentially adding further justification for utilizing phenols as model systems for investigating tyrosine-based dynamics.