Triplet Decay Dynamics in Sulfur Substituted Thymine: How Position of Substitution Matters.
Triplet Decay Dynamics in Sulfur Substituted Thymine: How Position of Substitution Matters.
复制标题
硫取代胸腺嘧啶中的三重态衰变动力学：取代位置的重要性。
DOI：
10.1021/acs.jpca.9b08214
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Anirban Hazra
中科院分区：
文献类型：
--
作者：
Meghna A. Manae;Anirban Hazra
根据硫取代位置的不同，胸腺嘧啶的硫取代类似物有三种类型：2-硫代胸腺嘧啶（2ththy）、4-硫代胸腺嘧啶（4ththy）和2,4-二硫代胸腺嘧啶（dththy）。已知这些分子在光激发下以三态形成，产率接近一致。因此，它们能够将基态分子氧光敏为单线态氧，这一特性使它们成为光动力治疗（PDT）的潜在药物。单线态氧产率与硫胸胺的三重态寿命直接相关，而三重态寿命又受其三重态衰变动力学的支配。本文通过对三种硫thymine的比较研究，探讨了三重态衰变动力学对硫取代位置的依赖性。发现2thy的三重态势能面拓扑结构和衰变机制与4thy和dthy有明显不同。其根本原因是每个分子中两个C=X （X=O， S）基团的电子性质不同，其中一个与C=C键共轭，而另一个则没有。此外，研究表明，通过不显眼的取代来操纵2thy分子轨道的能量顺序可以增加其三重态寿命，从而使其成为PDT药物的更好候选者。
Sulfur substituted analogues of thymine are of three types depending on the position of sulphur substitution: 2-thiothymine (2tThy), 4-thothymine (4tThy) and 2,4-dithiothymine (dtThy). These molecules on photoexcitation, are known to form in their triplet state with near unity yield. Consequently, they are able to photosensitize ground state molecular oxygen to singlet oxygen, a property which makes them potential drugs for photodynamic therapy (PDT). The singlet oxygen yield is directly correlated with the triplet lifetime of the thiothymine, which in turn is governed by its triplet decay dynamics. In this work, the dependence of the triplet decay dynamics on the position of sulfur substitution is investigated by comparatively studying all three thiothymines. The topology of the triplet potential energy surface and decay mechanism of 2tThy is found to be distinctly different from 4tThy and dtThy. The fundamental reason for this is the different electronic natures of the two C=X (X=O, S) moieties in each molecule, one of which is conjugated with a C=C bond, while the other is not. Further, it is shown that the triplet lifetime of 2tThy can be increased by manipulating the energetic ordering of its molecular orbitals with unobtrusive substitutions, thus making it a better candidate for a PDT drug.
影响因子：
2.9
作者：
Asturiol, David;Lasorne, Benjamin;Blancafort, Lluis
通讯作者：
Blancafort, Lluis