Raman and theoretical study of the solvent effects on the sizable intramolecular charge transfer in the push-pull 5-(dimethylamino)-5'-nitro-2,2'-bithiophene.
Raman and theoretical study of the solvent effects on the sizable intramolecular charge transfer in the push-pull 5-(dimethylamino)-5'-nitro-2,2'-bithiophene.
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拉曼和溶剂对推拉 5-(二甲氨基)-5-硝基-2,2-联噻吩中相当大的分子内电荷转移影响的理论研究。
DOI：
10.1021/jp052137n
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
J. T. López Navarrete
中科院分区：
文献类型：
--
作者：
E. Ortí;P. Viruela;R. Viruela;F. Effenberger;V. Hernández;J. T. López Navarrete
在本文中，我们通过不同极性溶剂中最强拉曼散射的频率和相对强度的变化，分析了推拉π共轭体系5-(二甲基氨基)-5'-硝基-2,2'-联噻吩的分子内电荷转移程度。密度泛函理论（DFT）被用作实验研究的支持。通过在 Tomasi 开发的极化连续介质模型 (PCM) 框架内执行 B3LYP/6-31G 计算，估计了溶剂对分子和电子结构以及振动特性的影响。计算表明，该分子在基态下高度极化，并且表现为非常有效的光诱导推拉系统。分子的极化随着溶剂极性的增加而强烈增加，并决定拉曼光谱的轮廓从一种溶剂到另一种溶剂以及进入固体时发生很大变化。与 nu(sym)(NO(2)) 拉伸相关的最强拉曼散射在从 CCl(4) 到固体的过程中经历了 48 cm(-1) 的下移。 DFT 计算提供了拉曼光谱随溶剂极性演变的综合解释。
In this paper, we analyze the degree of intramolecular charge transfer in a push-pull pi-conjugated system, 5-(dimethylamino)-5'-nitro-2,2'-bithiophene, from changes in frequencies and relative intensities of its strongest Raman scatterings in a bunch of solvents with different polarities. Density functional theory (DFT) was used as a support of the experimental study. Solvent effects on the molecular and electronic structures and on the vibrational properties were estimated by performing B3LYP/6-31G calculations within the framework of the polarized continuum model (PCM) developed by Tomasi. Calculations reveal that the molecule is highly polarized in the ground state and behaves as a very efficient photoinduced push-pull system. The polarization of the molecule strongly increases with solvent polarity and determines that the profile of the Raman spectra greatly changes from one solvent to another and in going to the solid. The strongest Raman scattering associated with the nu(sym)(NO(2)) stretching undergoes a downshift of 48 cm(-1) in passing from CCl(4) to the solid. DFT calculations provide a comprehensive interpretation of the evolution of the Raman spectra with solvent polarity.