A Fluorogenic Triphenyl‐Amine‐Naphthyl‐Hydrazide Probe Selective for Cu²⁺ and Cysteine Detection via an ON‐OFF‐ON Logic path with Real Applications

Abstract

1,1′‐((1E,1′E)‐((2E,2′E)(((phenylazanediyl)bis(4,1‐phenylene))bis‐(methanylylidene))bis‐ (hydrazine‐2,1‐diylidene))bis(methanylylidene))bis(naphthalen‐2‐ol), H2L shows high fluorescence emission (λem, 550 nm; λabs, 420 nm) which is selectively quenched by Cu2+ in presence of many other biologically important ions. The limit of detection (LOD), 7.3 nM is much lower than WHO recommended maximum permissible limit (20 μM) of Cu2+consumption in human body. The binding fashion of the probe to Cu2+ ion is 1 : 2 mole ratio and has been confirmed by Job's plot and ESI‐MS spectral data. The binding constant for Cu2+ is 4.93×1010 M−2 which also indicates sufficient stability and 1 : 2 complexation. On addition of cysteine to L‐Cu2+ensemble,the emission intensity (550 nm) enhances which accounts the release of Cu2+ from the non‐emissive complex and restores the total fluorogenic efficiency of probe, H2L (LOD (Cysteine), 36 nM). Thus, ON‐OFF‐ON mechanism of H2L has been utilized for selective and specific detection of Cu2+ and Cysteine over several other amino acids. In addition to this, the probe is treated on WI‐38 cell line to check cytotoxicity. This chemosensor, H2L has been successfully applied to examine intracellular trace quantity of Cu2+ and Cysteine concentration in Hep G2 Cell lines.

Naphthyl-azine – aggregation induced emission, reversible acidochromism, cyanide sensing and its application in intracellular imaging

“…1-Hydrazonomethyl-naphthalen-2-ol was synthesized based on a literature procedure 48 (Scheme 1). To a methanolic solution (10 mL) of 1-hydrazonomethyl-naphthalen-2-ol (0.186 mg, 1 mmol), 2-hydroxy-4,6-dimethoxy-benzaldehyde (0.182 mg, 1 mmol) in MeOH (5 ml) was added dropwise slowly.…”

Azophenyl appended Schiff base probe for colorimetric detection of Cu2+ in semi‐aqueous medium and live cell imaging

“…In addition, the binding constant (K a , 3.414 Â 10 7 M À1 ) of Cu-complex was determined using the Benesi-Hildebrand equation (section S4) from UV-vis titration data. [12] Recovery and reusability are the part of sustainable research. In present work, the probe has a strong binding ability towards Cu 2+ ion.…”

“…[7] Many reports already exist whereby metal ion, like Cu 2+ , has been successfully detected using spectrophotometric techniques. [8][9][10][11][12] The importance of Cu 2+ is numerous in the development of civilisation (The Copper Age!) and the sustenance of living bodies.…”

A novel lipid droplets‐targeting fluorescent probe based on dicyanisophorone and carbazole for Cu2+ and its application

“…1 H NMR (400 MHz, DMSOd 6 ) δ 12.06 (s, 1H), 8.77 (s, 1H), 8.71 (s, 2H), 8.48 (s, 1H), 8.12 (d, J = 7.7 Hz, 1H), 8.03 (t, J = 8.6 Hz, 1H), 7.86 (d, J = 9.6 Hz, 1H), 7.79 (d, J = 8.6 Hz, 1H), 7.67 (dd, J = 9.5, 8.3 Hz, 3H), 7.47 (d, J = 8.6 Hz, 2H), 6.86 (s, 1H), 4.41 (t, 2H), 2.58 (d, 4H), 1.78-1.70 (m, 2H), 1.29 (q, 2H), 1.01 (s, 6H), 0.86 (t, 3H). 13 C NMR (DMSO-d 6 , 151 MHz,) δ 170.78, 160.64, 157. 26, 150.48, 150.28, 148.96, 142.25, 141.99, 139.74, 138.50, 128.26, 127.75, 127.46, 126.54, 125.87, 123.16, 122.95, 122.04, 120.88, 120.56, 114.67, 113.88, 110.78, 75.24, 60.23, 42.81, 38.74, 32.20, 31.23, 27.98, 20.22, 14.19.…”

“…[11,12] In general, the normal range of copper involved in the human body is 15.7-23.6 μM. [13] The U.S. Environmental Protection Agency (EPA) requires that the copper content in drinking water be less than 20 μM. [14] When the concentration of Cu 2+ in drinking water is too high, it will have a bad impact on organisms.…”