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

作　　者：Zhe Shao Wen-Ying Zhang Ke Zhao 邵哲;张纹莹;赵珂(School of Physics and Electronics,Shandong Normal University,Jinan 250358,China)

机构地区：[1]School of Physics and Electronics,Shandong Normal University,Jinan 250358,China

出　　处：《Chinese Physics B》2022年第5期253-260,共8页中国物理B（英文版）

基　　金：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 Zn^(2+) 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 Zn^(2+) 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 probes4 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 Zn^(2+) 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 

分 类 号：O657.3[理学—分析化学]