Department of Physics, AlbaNova University Center , Stockholm University , SE-106 91 Stockholm , Sweden.
J Phys Chem B. 2019 Jul 5;123(26):5555-5567. doi: 10.1021/acs.jpcb.9b03084. Epub 2019 Jun 19.
2-Thiopyridone (2-TP), a common model system for excited-state proton transfer, has been simulated in aqueous solution with ab initio molecular dynamics. The interplay of electronic structure, protonation, and solvatization is investigated by comparison of three differently protonated molecular forms and between the lowest singlet and triplet electronic states. An interdependence clearly manifests in the mixed-character T state for the 2-TP form, systematic structural distortions of the 2-mercaptopyridine (2-MP) form, and photobase protolysis of the 2-TP form, in the aqueous phase. In comparison, simplified continuum models for the solvatization are found to be significantly inaccurate for several of the species. To facilitate future computational studies, we therefore present a minimal representative solvatization complex for each stable form and electronic state. Our findings demonstrate the importance of explicit solvatization of the compound and sets the stage for including it also in future studies.
2-硫代吡啶（2-TP）是一种常见的激发态质子转移模型体系，已通过从头算分子动力学在水溶液中进行了模拟。通过比较三种不同质子化的分子形式以及最低单重态和三重态电子态，研究了电子结构、质子化和溶剂化的相互作用。在水相中的 2-TP 形式的混合特征 T 态、2-巯基吡啶（2-MP）形式的系统结构变形以及 2-TP 形式的光致碱解中，明显表现出相互依存关系。相比之下，对于几种物种，简化的连续体溶剂化模型被发现存在显著的不准确性。因此，为了方便未来的计算研究，我们为每个稳定形式和电子态提供了一个最小代表性的溶剂化络合物。我们的发现表明了化合物的明确溶剂化的重要性，并为将来的研究也包括它奠定了基础。
