State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian, P R China.
Org Biomol Chem. 2011 May 21;9(10):3844-53. doi: 10.1039/c0ob00910e. Epub 2011 Apr 12.
Two highly selective OFF-ON green emitting fluorescent thiol probes (1 and 2) with intense absorption in the visible spectrum (molar extinction coefficient ε is up to 73 800 M(-1) cm(-1) at 509 nm) based on dyads of BODIPY (as electron donor of the photo-induced electron transfer, i.e.PET) and 2,4-dinitrobenzenesulfonyl (DNBS) (as electron acceptor of the PET process) were devised. The single crystal structures of the two probes were determined. The distance between the electron donor (BODIPY fluorophore) and the electron acceptor (DNBS) of probe 2 is larger than that of probe 1, as a result the contrast ratio (or the PET efficiency) of probe 2 is smaller than that of probe 1. However, fluorescence OFF-ON switching effects were observed for both probe 1 and probe 2 in the presence of cysteine (the emission enhancement is 300-fold for probe 1 and 54-fold for probe 2). The fluorescence OFF-ON sensing mechanism is rationalized by DFT/TDDFT calculations. We demonstrated with DFT calculations that DNBS is ca. 0.76 eV more potent to accept electrons than the maleimide moiety. The probes were used for fluorescent imaging of cellular thiols.
基于二聚体 BODIPY（作为光诱导电子转移的电子给体，即 PET）和 2,4-二硝基苯磺酰基（DNBS）（作为 PET 过程的电子受体），设计了两种具有强可见光吸收（摩尔消光系数 ε 在 509nm 时高达 73800M-1cm-1）的高选择性 OFF-ON 绿色发射荧光硫醇探针（1 和 2）。测定了两种探针的单晶结构。探针 2 的电子给体（BODIPY 荧光团）和电子受体（DNBS）之间的距离大于探针 1，因此探针 2 的对比度（或 PET 效率）小于探针 1。然而，在半胱氨酸存在下，探针 1 和探针 2 均观察到荧光 OFF-ON 开关效应（探针 1 的发射增强 300 倍，探针 2 的发射增强 54 倍）。通过 DFT/TDDFT 计算合理化了荧光 OFF-ON 传感机制。我们通过 DFT 计算证明，DNBS 比马来酰亚胺部分更有效地接受电子，约为 0.76eV。探针用于细胞硫醇的荧光成像。
