Department of Physics, Liaoning University, Shenyang, 110036, P. R. China.
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P. R. China.
Sci Rep. 2017 May 8;7(1):1574. doi: 10.1038/s41598-017-01780-7.
The new competitive mechanism of intermolecular and intramolecular hydrogen bond can be proposed with an improved mixed model. Upon the photoinduced process, the twisting intramolecular charge transfer (TICT) structure of the hydroxyphenyl imidazo [1, 2-a] pyridine (HPIP) can be obtained. TICT character prompts the fluorescent inactivation via non-radiative decay process. For exploring the photochemical and photophysical properties, the electronic spectra and the infrared (IR) vibrational spectra of titled compounds have been detailedly investigated. In addition, the frontier molecular orbitals (MOs) analysis visually reveals that the unbalanced electron population can give rise to the torsion of molecular structure. To further give an attractive insight into the non-radiative decay process, the potential energy curves have been depicted on the ground state (S), the first excited state (S) and the triple excited state (T). Minimum energy crossing point (MECP) has been found in the S and T state. On the MECP, the intersystem crossing (ISC) might be dominant channel. The density functional theory (DFT) and the time-dependent density functional theory (TDDFT) methods have been throughout employed in the S state, T state and S state, respectively. The theoretical results are consistent with experiment in mixed and PCM model.
可以提出改进的混合模型，以提出分子间和分子内氢键的新竞争机制。在光诱导过程中，可以得到羟苯基咪唑并[1,2-a]吡啶（HPIP）的扭转分子内电荷转移（TICT）结构。TICT 特征通过非辐射衰减过程促使荧光失活。为了探索光化学和光物理性质，详细研究了标题化合物的电子光谱和红外（IR）振动光谱。此外，前沿分子轨道（MOs）分析直观地表明，不平衡的电子分布会导致分子结构的扭转。为了进一步深入了解非辐射衰减过程，已经描绘了基态（S）、第一激发态（S）和三重激发态（T）上的势能曲线。在 S 和 T 态中发现了最低能量交叉点（MECP）。在 MECP 上，体系间窜越（ISC）可能是主要通道。在 S 态、T 态和 S 态中分别使用了密度泛函理论（DFT）和含时密度泛函理论（TDDFT）方法。理论结果与混合和 PCM 模型中的实验结果一致。
