A NIR fluorescent probe for the detection and visualization of hydrogen sulfide using the aldehyde group assisted thiolysis of dinitrophenyl ether strategy

Abstract

A NIR fluorescent probe exploiting the aldehyde group assisted thiolysis of dinitrophenyl ether strategy for H2S imaging in cells, tissues and mice.

Fluorescent probes based on nucleophilic aromatic substitution reactions for reactive sulfur and selenium species: Recent progress, applications, and design strategies

“…The introduction of RSS reactive groups (such as Michael acceptors, disulfide bond compounds, etc.) following other mechanisms in the vicinity of the active site (whether fluorophore or detection group) is beneficial for improving the reactivity at this site and the selectivity for the test substance [103] , [230] , [270] , [285] . Bridging the fluorophore and detection group with piperidine has been shown to be helpful for improving the sensitivity of the tested substance and greatly shortens the detection time [250] .…”

“…Wang et al appended a 3,5-dinitrophenyl-O ether group on the dicyanoisophorone fluorophore and introduced a formaldehyde group at an ortho position of the phenyl-O ether to synthesize a fluorescent probe for detecting H 2 S. With phenyl-O ether lacking the ortho formaldehyde group, the response of the probe to H 2 S was very slow. Introducing the ortho formaldehyde group (Michael acceptor) as an auxiliary detection group caused HS – to induce an initial nucleophilic addition reaction on the aldehyde group, and then reaction of the phenyl-O ether bond eventually formed 3,5-dinitrothiophenol [270] . 2-Fluoro-5-nitrobenzoate is a notable specific group.…”

“…However, due to steric hindrance, the rate of reaction of PhSH is significantly slower than that with H 2 S. Unfortunately, PhSH has not been included in reported selective experiments on fluorescent probes for H 2 S. The 3,5-dinitrophenyl-O ether group ( Fig. 17 , panel 49 ) [270] showed a very slow response to H 2 S. Since the NBD group produces different fluorescence emissions when it is incorporated into different structures, NBD-O ether ( Fig. 17 , panel 52 ) [279] can be used for distinguishing between Cys/Hcy and GSH, and the reaction rates with PhSH and H 2 S are very slow.…”

“…

Fig. 17 Comparison of the same fluorophore with different detection groups (probes 46–53) [270] , [271] , [272] , [273] , [274] , [275] , [276] , [277] , [278] , [279] , [280] .

…”

“…It is a good choice to introduce a formaldehyde group (Michael acceptor) in the ortho position of the fluorophore. The formaldehyde group first reacts with RSS to form activated S − , and then undergoes S N Ar reaction with the phenyl-O ether bond [270] . When the detection group is phenyl-Se ether and a formaldehyde group is introduced adjacent to the detection site of the fluorophore, one GSH molecule can react with two detection groups at the same time, resulting in a more conjugated system, whereas Cys or Hcy can only react with one of the detection groups [103] .…”