中国物理B ›› 2022, Vol. 31 ›› Issue (5): 53302-053302.doi: 10.1088/1674-1056/ac46c6

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Computational design of ratiometric two-photon fluorescent Zn2+ probes based on quinoline and di-2-picolylamine moieties

Zhe Shao(邵哲), Wen-Ying Zhang(张纹莹), and Ke Zhao(赵珂)   

  1. School of Physics and Electronics, Shandong Normal University, Jinan 250358, China
  • 收稿日期:2021-09-03 修回日期:2021-12-17 出版日期:2022-05-14 发布日期:2022-04-18
  • 通讯作者: Ke Zhao,E-mail:zhaoke@sdnu.edu.cn E-mail:zhaoke@sdnu.edu.cn
  • 基金资助:
    Project supported by the Shandong Provincial Natural Science Foundation,China (Grant No.ZR2020MA078).

Computational design of ratiometric two-photon fluorescent Zn2+ probes based on quinoline and di-2-picolylamine moieties

Zhe Shao(邵哲), Wen-Ying Zhang(张纹莹), and Ke Zhao(赵珂)   

  1. School of Physics and Electronics, Shandong Normal University, Jinan 250358, China
  • Received:2021-09-03 Revised:2021-12-17 Online:2022-05-14 Published:2022-04-18
  • Contact: Ke Zhao,E-mail:zhaoke@sdnu.edu.cn E-mail:zhaoke@sdnu.edu.cn
  • About author:2021-12-29
  • Supported by:
    Project supported by the Shandong Provincial Natural Science Foundation,China (Grant No.ZR2020MA078).

摘要: To improve two-photon absorption (TPA) response of a newly synthesized probe, a series of ratiometric two-photon fluorescent Zn2+ sensors based on quinoline and DPA moieties have been designed. The one-photon absorption, TPA, and emission properties of the experimental and designed probes before and after coordination with Zn2+ are investigated employing the density functional theory in combination with response functions. The design consists of two levels. In the first level of design, five probes are constructed through using several electron acceptors or donors to increase accepting or donating ability of the fluorophores. It shows that all the designed probes have stronger TPA intensities at longer wavelengths with respect to the experimental probe because of the increased intra-molecular charge transfer. Moreover, it is found that the probe 4 built by adding an acyl unit has the largest TPA cross section among the designed structures due to the form of longer conjugated length and more linear backbone. One dimethylamino terminal attached along the skeleton can improve TPA intensity more efficiently than two side amino groups. Therefore, in the second level of design, a new probe 7 is formed by both an acyl unit and a dimethylamino terminal. It exhibits that the TPA cross sections of probe 7 and its zinc complex increase dramatically. Furthermore, the fluorescence quantum yields of the designed probes 4 and 7 are calculated in a new way, which makes use of the relation between the computed difference of dipole moment and the measured fluorescence quantum yield. The result shows that our design also improves the fluorescence quantum yield considerably. All in all, the designed probes 4 and 7 not only possess enhanced TPA intensities but also have large differences of emission wavelength upon Zn2+ coordination and strong fluorescence intensity, which demonstrates that they are potential ratiometric two-photon fluorescent probes.

关键词: two-photon absorption, fluorescent probe, zinc ion, intra-molecular charge transfer

Abstract: To improve two-photon absorption (TPA) response of a newly synthesized probe, a series of ratiometric two-photon fluorescent Zn2+ sensors based on quinoline and DPA moieties have been designed. The one-photon absorption, TPA, and emission properties of the experimental and designed probes before and after coordination with Zn2+ are investigated employing the density functional theory in combination with response functions. The design consists of two levels. In the first level of design, five probes are constructed through using several electron acceptors or donors to increase accepting or donating ability of the fluorophores. It shows that all the designed probes have stronger TPA intensities at longer wavelengths with respect to the experimental probe because of the increased intra-molecular charge transfer. Moreover, it is found that the probe 4 built by adding an acyl unit has the largest TPA cross section among the designed structures due to the form of longer conjugated length and more linear backbone. One dimethylamino terminal attached along the skeleton can improve TPA intensity more efficiently than two side amino groups. Therefore, in the second level of design, a new probe 7 is formed by both an acyl unit and a dimethylamino terminal. It exhibits that the TPA cross sections of probe 7 and its zinc complex increase dramatically. Furthermore, the fluorescence quantum yields of the designed probes 4 and 7 are calculated in a new way, which makes use of the relation between the computed difference of dipole moment and the measured fluorescence quantum yield. The result shows that our design also improves the fluorescence quantum yield considerably. All in all, the designed probes 4 and 7 not only possess enhanced TPA intensities but also have large differences of emission wavelength upon Zn2+ coordination and strong fluorescence intensity, which demonstrates that they are potential ratiometric two-photon fluorescent probes.

Key words: two-photon absorption, fluorescent probe, zinc ion, intra-molecular charge transfer

中图分类号:  (Molecular spectra)

  • 33.20.-t
42.65.-k (Nonlinear optics) 82.30.Fi (Ion-molecule, ion-ion, and charge-transfer reactions)