College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, PR China.
Department of Chemistry, Anhui Province Key Laboratory of Functional Inorganic Materials, Anhui University, Hefei 230039, PR China.
Analyst. 2022 Nov 21;147(23):5495-5507. doi: 10.1039/d2an01207c.
Three novel imidazole-based two-photon absorption compounds bearing different organic cations (1PIPy, 2PIQu, and 3PIIm) were facilely synthesized and fully characterized by H NMR, C NMR, FT-IR, and HRMS. The linear and nonlinear photophysical properties of the target compounds were systematically investigated in various solvents, supplemented with the density functional theory calculations to shed light on their structure-property relationships. The maximum two-photon action cross-sections ( × ) were determined to be 22.4-98.2 (CHCl), 9.6-41.3 (DMF), and 3.9-11.8 (HO) GM. It is found that 3PIIm shows significant viscosity sensitivity with a sharp 27-fold increase in fluorescence intensity. Its fluorescence intensity also exhibits a linear relationship with the viscosity of the media in a logarithmic plot. The × value of 3PIIm in highly viscous glycerol was found to be 107.5 GM. Cytotoxicity tests indicate that these compounds have relatively low cytotoxicity. All the target compounds were successfully characterized by one- and two-photon fluorescence imaging in living cells. The colocalization experiments reveal that 1PIPy and 3PIIm are specially located in the endoplasmic reticulum (ER) with the Pearson's coefficients above 0.90. 3PIIm can also monitor the fluctuation of ER viscosity during etoposide-induced apoptosis.
三种新型基于咪唑的双光子吸收化合物，分别带有不同的有机阳离子（1PIPy、2PIQu 和 3PIIm），通过 1H NMR、13C NMR、FT-IR 和 HRMS 进行了简便的合成和充分的表征。目标化合物的线性和非线性光物理性质在各种溶剂中进行了系统的研究，辅以密度泛函理论计算，以阐明它们的结构-性质关系。测定的最大双光子吸收截面（×）分别为 22.4-98.2（CHCl3）、9.6-41.3（DMF）和 3.9-11.8（H2O）GM。发现 3PIIm 具有显著的粘度敏感性，荧光强度增加了 27 倍。其荧光强度与介质粘度在对数图中也呈线性关系。在高粘度的甘油中，3PIIm 的 × 值为 107.5 GM。细胞毒性试验表明，这些化合物的细胞毒性相对较低。所有目标化合物都成功地通过活细胞的单光子和双光子荧光成像进行了表征。共定位实验表明，1PIPy 和 3PIIm 特别位于内质网（ER）中，Pearson 系数大于 0.90。3PIIm 还可以监测依托泊苷诱导凋亡过程中 ER 粘度的波动。
