A Near-Infrared Fluorescent Probe for Recognition of Hypochlorite Anions Based on Dicyanoisophorone Skeleton

Abstract

A novel near-infrared (NIR) fluorescent probe (SWJT-9) was designed and synthesized for the detection of hypochlorite anion (ClO−) using a diaminomaleonitrile group as the recognition site. SWJT-9 had large Stokes shift (237 nm) and showed an excellent NIR fluorescence response to ClO− with the color change under the visible light. It showed a low detection limit (24.7 nM), high selectivity, and rapid detection (within 2 min) for ClO−. The new detection mechanism of SWJT-9 on ClO− was confirmed by 1H NMR, MS spectrum, and the density functional theory (DFT) calculations. In addition, the probe was successfully used to detect ClO− in HeLa cells.

A Turn-On and Colorimetric Probe Based on Isophorone Skeleton for Detecting Nerve Agent Mimic Diethyl Chlorophosphite

“…The hydroxyl group is a common nucleophile and is prone to react with the highly reactive chlorophosphate group of DCP [ 48 , 49 ]. Then, the probe SWJT-20 was designed using isophorone as the fluorophore and the hydroxyl group as a recognition site ( Scheme 1 ), which was synthesized by compound 2 [ 50 ]. In addition, an aldehyde group was introduced into the ortho position of hydroxyl group in compound 2 by Duff reaction [ 51 ] to obtain SWJT-20 [ 52 ], which was characterized using 1 H, 13 C NMR spectra, and HRMS ( Figures S1–S3, Supplementary Materials ).…”

“…As shown in Scheme 1 , compounds 1 and 2 were synthesized according to our previous study [ 50 , 55 ]. The synthetic process of SWJT-20 was performed using a known literature approach [ 52 ].…”

“…Synthesis of compound 1 [ 50 , 55 ]: Isophorone (50.02 g, 361.77 mmol) and malononitrile (23.9 g, 361.77 mmol) were placed in a 500-mL round-bottom flask and dissolved by adding 250 mL of ethanol (until no delamination). After stirring for 5 min, 5 mL of piperidine was added.…”

“…Synthesis of compound 2 [ 50 , 55 ]: Compound 1 (9.0 g, 48.32 mmol) and 3-methoxy-4-hydroxybenzaldehyde (8.82 g, 57.98 mmol) were placed in a 250-mL round bottom flask and dissolved by adding 80 mL of ethanol. After 5 min, 2 mL of piperidine was added, and the reaction mixture was stirred and refluxed for 7 h. Then, part of the solvent was removed under vacuum, and the resulting residue was crystallized overnight at 4 °C in a refrigerator, and filtered on the next day to obtain the crude product.…”

A ratiometric, colorimetric fluorescent probe with a large emission shift for the rapid detection of diethyl chlorophosphate

“…Compounds 1 , 2 and 3 (Scheme S1, ESI†) were synthesized according to our reported work. 47,48 Compound 3 (50 mg, 0.1 mmol) was dissolved in 2.0 mL of ethanol by stirring this mixture for 5 minutes. Into the resulting solution were added one drop of piperidine and then malononitrile (18.9 mg, 0.2 mmol), and the resulting mixture was stirred for 30 minutes at room temperature.…”