Theoretical reconsideration of the mechanism of the excited state proton transfer of indigo carmine in water

Zhu, Ling; Zhou, Qiao; Cao, Bifa; Li, Bo; Wang, Zhengran; Zhang, Xinglei; Yin, Hao; Shi, Ying

doi:10.1016/j.molliq.2021.118365

Cited by 18 publications

(9 citation statements)

References 49 publications

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“…The dynamic photoinduced charge transfer of G–C was quantified by examining its charge density difference (CDD). 39–42 Fig. 4 and Movie S1 (ESI†) illustrate the CDD real-time calculations of G–C.…”

Section: Resultsmentioning

confidence: 99%

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The dynamical temporal behaviors of guanine–cytosine coherent charge transfer

Zhu

Zhou

Wan

et al. 2023

Phys. Chem. Chem. Phys.

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Section: Resultsmentioning

confidence: 99%

“…The dynamic photoinduced charge transfer of G-C was quantified by examining its charge density difference (CDD). [39][40][41][42] Fig. 4 and Movie S1 (ESI †) illustrate the CDD real-time calculations of G-C. Purple represents photoinduced holes, corresponding to a decreasing region of CDD.…”

Section: Charge Density Differencementioning

confidence: 99%

The dynamical temporal behaviors of guanine–cytosine coherent charge transfer

Zhu

Zhou

Wan

et al. 2023

Phys. Chem. Chem. Phys.

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“…利用 DFT [19][20][21] 和 TD-DFT [22][23][24][25] 方法， B3LYP 泛函 [26,27] 和 tzvp 基组 [28,29] 分别优化获得了 HBT-OMe 及其产物分子的基态(S 0 )和第一激发态(S 1 )的几何构型。基于此结构，我们计算得到了 HBT-OMe 分子、产物分子的 Enol 和 Keto 形式下基态(S 0 )和第一激发态(S 1 )的几何构型在 S 0 态和 S 1 态的键长、键角、前线分子轨道等信息以及产物分子的红外(IR)振动光谱、势能曲线。为了更好地描述实验结果，我们选用环己烷作为溶剂，并采用 SCRF(self consistent reaction field)理论中的连续介质模型(the polarizable continuum model with the integral equation formalism variant， IEFPCM)来计算溶剂效应 [30,31] 前线分子轨道前线分子轨道有助于帮助我们了解分子激发态跃迁时电荷分布变化情况…”

Section: 研究方法unclassified

Mechanism of fluorescence enhancement of HClO detected by excited-state intramolecular proton transfer based HBT-OMe molecule

Li¹,

Yang²

2023

Acta Phys. Sin.

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The molecule with excited state intramolecular transfer (ESIPT) has a wide application in fluorescent probe, biology imaging and light-emitting materials etc. Biologically active oxygen hypochlorite (HClO) is widely present in the biological and chemical environment, which can pose a significant risk to human health. Design HClO-sensitive molecular in solvent is essential. Recently, Wu et al. designed an ESIPT-based HBT-OMe probe molecule, which can detect HClO due to its methoxy-hydroxy-benzothiazole. They found that the fluorescence intensity of the system gradually increases with increasing HClO. However, the microscopic mechanism of this highly efficient fluorescent probe is not well understood. Therefore, in this research, we theoretically investigate the ESIPT mechanism of the HBT-Ome and its product molecule using density functional theory and time-dependent density functional theory method. Based on polarizable continuum model (PCM) with the integral equation formalism variant (IEFPCM) and Becke’s three-parameter hybrid exchange function with the Lee-Yang-Parr gradient-corrected functional (B3LYP) as well as the TZVP basis, the optimized structures were obtained. The structures show the tendency of the HBT-Ome product molecule to undergo proton transfer in the excited state and HBT-OMe molecules cannot undergo proton transfer processes. The frontier molecular orbitals analysis not only explains the reason of the enhanced fluorescence of the HBT-Ome product, but also demonstrates that the HBT-Ome fluorescence intensity is diminished due to twisted intramolecular charge transfer in the excited state. It is twisted intramolecular charge transfer that leads to smaller charge density overlap and further causes weakness of fluorescence intensity of HBT-OMe molecule. Infrared vibrational spectrum shows the enhancement of intramolecular hydrogen bond of O-H, which indicates the tendency of proton transfer. Based on the molecular covalent interaction analysis, we can see that the intramolecular interactions of HBT-OMe remain largely unchanged clearly. Intramolecular O-H bonding interaction is weakened and N-H bonding interaction is increased for HBT-OMe product molecule. The enhancement of intramolecular hydrogen bond of N-H and further illustrates the trend of proton transfer. The calculated potential energy curve provides direct evidence for the occurrence of ESIPT in the HBT-Ome product molecule. Our work is important to design and synthesis of HClO fluorescent probes based on ESIPT molecules.

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“…[1][2][3][4][5][6] Consequently, several researchers have used the mechanism of ESIPT in various systems. [7][8][9][10] Also, the various proton transfers (PTs) in chemical and biological reactions have been studied to tune photophysical properties. [11][12][13] In particular, previous studies on ESIPT have found that external hydrogen bonding can affect the PT process.…”

Section: Introductionmentioning

confidence: 99%