基于噻吩撑乙炔的线性共轭寡聚物的激发态结构弛豫的奇偶效应
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- 英文论文题名：Odd–Even Alternation of the Excited State Relaxation of Oligo(Thienyl ethynylene)s-Cored Chromophores Incorporating Truxene units as π-Donating End-Groups
- 论文作者：王娴 ; 郭前进 ; 夏安东
- 英文论文作者：Xian Wang ; Qianjin Guo ; Andong Xia ; Institute of Chemistry ; Chinese Academy of Sciences
- 年：2016
- 作者机构：中国科学院化学研究所;
- 论文关键词：寡聚噻吩撑乙炔 ; 奇偶效应 ; 瞬态吸收光谱
- 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-第四十四分会：化学动力学
- 语种：中文
- 分类号：O631.1
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第四十四分会 ; 化学动力学
- 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：287k
- 原文格式：D
- 会议级别：全国
摘要
一系列具有不同共轭长度的线性共轭寡聚物Tr(TE)nT r(n=2–6),由"噻吩撑乙炔"寡聚物(OTE)两端分别修饰一个三聚茚基团(Tr)而成。本工作中,我们基于含时密度泛函DFT理论和瞬态吸收光谱,研究了其激发态动力学分别与分子构型和溶剂环境的相关性。以π-π*激发,溶解在非极性溶剂环己烷中的Tr(TE)n Tr系列分子的结构弛豫过程中出现奇偶交替现象。对于具有偶数噻吩环(n=2,4,6)的分子,其发生在离域激发态的结构弛豫时间常数为~10 ps;具有奇数噻吩环(n=3,5)的分子,其结构弛豫时间常数为~2 ps。量子气相计算结果表明奇数噻吩环的分子激发态结构趋于扭曲,而偶数噻吩环的分子激发态结构趋于平面。但在极性溶剂四氢呋喃中,没有激发态结构弛豫的奇偶效应出现。这是由于受四氢呋喃极性溶剂场作用,该系列分子的基态结构扭曲,导致其激发态结构也易于扭曲来降低自身能量。
A series of thienyl-ethynylene oligomers with two terminal truxene groups of 2–6 repeat thiophene rings have been analyzed using methods of DFT and ultrafast time-resolved absorption for examining the structure–property relationships and solvent dependence of the excited state dynamics. An odd–even alternation in the structural relaxation can be seen upon π-π* excitation of Tr(TE)n Tr(n = 2–6) molecules in nonpolar solvent cyclohexane. Geometry relaxation occurs on the initial delocalized state with a time constant of ~10 ps for even numbers(n = 2, 4, 6), and ~2 ps for the rest(n = 3, 5). Quantum gas-phase calculations reveal that the excited chromophores with odd number of thiophene rings fashion with twisted backbones, while the even-numbered isomers orient to planar. In tetrahydrofuran, instead, twisting structures are formed dominantly in the ground states. Furthermore, the excited states are fond of relaxation to lower the conjugation extent.
A series of thienyl-ethynylene oligomers with two terminal truxene groups of 2–6 repeat thiophene rings have been analyzed using methods of DFT and ultrafast time-resolved absorption for examining the structure–property relationships and solvent dependence of the excited state dynamics. An odd–even alternation in the structural relaxation can be seen upon π-π* excitation of Tr(TE)n Tr(n = 2–6) molecules in nonpolar solvent cyclohexane. Geometry relaxation occurs on the initial delocalized state with a time constant of ~10 ps for even numbers(n = 2, 4, 6), and ~2 ps for the rest(n = 3, 5). Quantum gas-phase calculations reveal that the excited chromophores with odd number of thiophene rings fashion with twisted backbones, while the even-numbered isomers orient to planar. In tetrahydrofuran, instead, twisting structures are formed dominantly in the ground states. Furthermore, the excited states are fond of relaxation to lower the conjugation extent.
引文
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[2]Donehue,J.;Varnavski,O.;Cemborski,R.;Iyoda,M.;Goodson,T.J.Am.Chem.Soc.2011,133:4819.
[2]Donehue,J.;Varnavski,O.;Cemborski,R.;Iyoda,M.;Goodson,T.J.Am.Chem.Soc.2011,133:4819.