通过二甲基亚砜改变分子内至分子间的氢键：香豆素343电荷转移的TDDFT研究
Altering intra- to inter-molecular hydrogen bonding by dimethylsulfoxide: A TDDFT study of charge transfer for coumarin 343.
作者信息
Liu Xiaochun, Yin Hang, Li Hui, Shi Ying
机构信息
Institute of Atomic and Molecular Physics, Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, Changchun 130012, China.
Institute of Atomic and Molecular Physics, Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, Changchun 130012, China.
出版信息
Spectrochim Acta A Mol Biomol Spectrosc. 2017 Apr 15;177:1-5. doi: 10.1016/j.saa.2017.01.022. Epub 2017 Jan 12.
DFT and TDDFT methods were carried out to investigate the influences of intramolecular and intermolecular hydrogen bonding on excited state charge transfer for coumarin 343 (C343). Intramolecular hydrogen bonding is formed between carboxylic acid group and carbonyl group in C343 monomer. However, in dimethylsulfoxide (DMSO) solution, DMSO 'opens up' the intramolecular hydrogen bonding and forms solute-solvent intermolecular hydrogen bonded C343-DMSO complex. Analysis of frontier molecular orbitals reveals that intramolecular charge transfer (ICT) occurs in the first excited state both for C343 monomer and complex. The results of optimized geometric structures indicate that the intramolecular hydrogen bonding interaction is strengthened while the intermolecular hydrogen bonding is weakened in excited state, which is confirmed again by monitoring the shifts of characteristic peaks of infrared spectra. We demonstrated that DMSO solvent can not only break the intramolecular hydrogen bonding to form intermolecular hydrogen bonding with C343 but also alter the mechanism of excited state hydrogen bonding strengthening.
采用密度泛函理论（DFT）和含时密度泛函理论（TDDFT）方法研究了分子内和分子间氢键对香豆素343（C343）激发态电荷转移的影响。在C343单体中，羧酸基团和羰基之间形成了分子内氢键。然而，在二甲基亚砜（DMSO）溶液中，DMSO “打开” 了分子内氢键，并形成了溶质 - 溶剂分子间氢键结合的C343 - DMSO复合物。前线分子轨道分析表明，C343单体和复合物在第一激发态均发生分子内电荷转移（ICT）。优化几何结构的结果表明，激发态下分子内氢键相互作用增强，而分子间氢键减弱，这通过监测红外光谱特征峰的位移再次得到证实。我们证明，DMSO溶剂不仅可以破坏分子内氢键与C343形成分子间氢键，还可以改变激发态氢键增强的机制。
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