Reaction‐Based Fluorescent Probe for Detection of Endogenous Cyanide in Real Biological Samples

Abstract

Herein, two compounds (1 a and 1 b) were rationally constructed as novel reaction-based fluorescent probes for CN(-) by making use of the electron-withdrawing ability of the cyano group that was formed from the sensing reaction. Notably, this design strategy was first employed for the development of fluorescent CN(-) probes. The experimental details showed that probe 1 a exhibited a fluorescence turn-on response to CN(-), whereas other anions, biological thiols, and hydrogen sulfide gave almost no interference. The detection limit of probe 1 a for CN(-) was found to be 0.12 μM. The sensing reaction product of 1 a with CN(-) was characterized by NMR spectroscopy and mass spectrometry. TD-DFT calculations demonstrated that the formed cyano group drives the intramolecular charge transfer (ICT) process from coumarin dye to the cyano group and thus the original strong ICT from the coumarin dye to the 3-position pyridyl vinyl ketone substituent is weakened, which results in recovery of coumarin fluorescence. The practical utility of 1 a was also examined. By fabricating paper strips, probe 1 a can be used as a simple tool to detect CN(-) in field measurements. Moreover, probe 1 a has been successfully applied for quantitative detection of endogenous CN(-) from cassava root.

Selective Detection of Cyanide in Water and Biological Samples by an Off-the-Shelf Compound

“…Many metal complexes are known in the literature for the detection of cyanide using colorimetric and fluorescent approaches. However, most of these reported complexes needed expensive reactants, − multistep synthesis of ligand, − purification by different separation techniques, and different characterization techniques were required, and they are very time-consuming. To avoid the multistep synthesis and characterization, we have found that an off-the-shelf compound, 6,7-dihydroxycoumarin ( 1 ), is suitable to make a complex with copper in water and thereby binds with cyanide ion in water.…”

Coumarin-Based Small-Molecule Fluorescent Chemosensors

“…The mechanisms of fluorescent sensing CN – with coumarin derivatives are mainly based on the nucleophilic addition on the coumarin − or the displacement of coumarin from coumarin-copper complexes . Among the chemosensors based on nucleophilic addition mechanism, CN – reactive sites include the 4-position of the coumarin group, − and polarized C  C , ,,− C  N , − and C – N , bonds conjugated to coumarin.…”

A Metal‐Organic Framework with Allyloxy Functionalization for Aqueous‐Phase Fluorescence Recognition of Pd(II) Ion

“…The equation LOD=3σ/ K was utilized to deduce the limit of detection (LOD) (Figure S13) [21] . The calculated LOD value was 1.48×10 −7 M (26.24 ppb).…”