对羟基苯吡啶激发态分子内质子转移的非绝热动力学模拟
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- 英文论文题名：Excited-state intramolecular proton transfer to carbon atoms in 4-(2'-hydroxyphenyl)pyridine
- 论文作者：郭巍巍 ; 崔刚龙 ; 方维海
- 英文论文作者：Wei-Wei Guo ; Ganglong Cui ; Wei-Hai Fang ; Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education ; Department of Chemistry ; Beijing Normal University
- 年：2016
- 作者机构：北京师范大学化学学院理论与计算光化学教育部重点实验室;
- 论文关键词：激发态分子内质子转移 ; 电子结构计算 ; 非绝热动力学模拟
- 会议召开时间：2016-07-01
- 会议录名称：中国化学会第30届学术年会摘要集-第十九分会：化学中的量子与经典动力学
- 语种：中文
- 分类号：O626.32
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第十九分会 ; 化学中的量子与经典动力学
- 会议地点：中国辽宁大连
- 主办单位：中国化学会
- 学会名称：中国化学会
- 页数：1
- 文件大小：212k
- 原文格式：D
- 会议级别：全国
摘要
极性原子间的激发态质子转移已得到实验和理论的广泛研究,~([1])而激发态质子转移至中性原子比如碳原子的相关工作较少。本文采用高精度电子结构计算方法(CASSCF/CASPT2)并结合OM2/MRCI半经验非绝热动力学模拟方法系统地研究了4-2'-对羟基苯吡啶分子的光物理和光化学过程。~([2-4])计算结果表明该分子经光激发到S_1态后,存在两条激发态弛豫通道。第一条是体系通过S_1激发态质子转移到达更稳定的酮式S_1极小点,再经S_1/S_0交叉点失活到电子基态;然后,一部分轨迹到酮式S_0极小点;另一部分轨迹通过基态分子内氢转移回到醇式S_0极小点。第二条是体系直接经过醇式的交叉点失活到醇式S_0极小点。
Excited-state intramolecular proton transfer(ESIPT) processes is of great significance to molecular and biochemical systems. In this work, we study ESIPT to carbon atoms since there has been plenty of work on ESIPT between two highly electronegative atoms. we have employed CASSCF, CASPT2, OM2/MRCI and DFT methods to present electronic structure calculations and non-adiabatic dynamics simulations on the mechanistic photochemistry of 4-(2'-hydroxyphenyl)pyridine. On the basis of our present results, we find that irradiation of 4-(2'-hydroxyphenyl)pyridine populates the bright S_1 state, which may undergo ESIPT to the more stable S_1 keto species. There are two S_1/S_0 conical intersections that mediate relaxation to the ground state, one in the enol region and one in the keto region, with the latter one substantially lower in energy. After S_1→S_0 internal conversion, the transient keto species can return back to the S_0 enol structure. Most of trajectories provided by surface-hopping simulations decay to the ground state via the S_1/S_0 conical intersection in the keto region, and the others via the enol region. The insights gained from present work may help to understand the ESIPT processes of molecules with intramolecular hydrogen bonds.
Excited-state intramolecular proton transfer(ESIPT) processes is of great significance to molecular and biochemical systems. In this work, we study ESIPT to carbon atoms since there has been plenty of work on ESIPT between two highly electronegative atoms. we have employed CASSCF, CASPT2, OM2/MRCI and DFT methods to present electronic structure calculations and non-adiabatic dynamics simulations on the mechanistic photochemistry of 4-(2'-hydroxyphenyl)pyridine. On the basis of our present results, we find that irradiation of 4-(2'-hydroxyphenyl)pyridine populates the bright S_1 state, which may undergo ESIPT to the more stable S_1 keto species. There are two S_1/S_0 conical intersections that mediate relaxation to the ground state, one in the enol region and one in the keto region, with the latter one substantially lower in energy. After S_1→S_0 internal conversion, the transient keto species can return back to the S_0 enol structure. Most of trajectories provided by surface-hopping simulations decay to the ground state via the S_1/S_0 conical intersection in the keto region, and the others via the enol region. The insights gained from present work may help to understand the ESIPT processes of molecules with intramolecular hydrogen bonds.
引文
[1]Cui,G.L.;Lan,Z.G.;Walter,T.J.Am.Chem.Soc.2012,134:1662
[2]Xia,S.H.;Xie,B.B.;Fang,Q.;Cui,G.L.;Walter,T.Phys.Chem.Chem.Phys.2015,17:9687
[3]Nikola,B.;Peter,W.Photochem.Photobiol.Sci.2006,5:656
[4]Cui,G.L.;Walter,T.J.Chem.Phys.2014,141:124101
[2]Xia,S.H.;Xie,B.B.;Fang,Q.;Cui,G.L.;Walter,T.Phys.Chem.Chem.Phys.2015,17:9687
[3]Nikola,B.;Peter,W.Photochem.Photobiol.Sci.2006,5:656
[4]Cui,G.L.;Walter,T.J.Chem.Phys.2014,141:124101
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