A naked-eye fluorescent sensor for copper(II) ions based on a naphthalene conjugate Bodipy dye

Abstract

A novel naphthalene-Bodipy dye (N-Bodipy) was designed, prepared and characterized. N-Bodipy showed a selective and sensitive recognition toward Cu(ii) ions as a fluorescent antenna group in acetonitrile/water over other metal cations. The complexation between Cu(ii) ions and N-Bodipy gave a specific color change as well as caused fluorescence quenching under long-wavelength light (365 nm). The remarkable quenching effect in fluorescence intensity centered at 538 nm was only observed in the presence of copper(ii) ions. Moreover, the orange color of N-Bodipy solution turned pale-yellow depending on the complexation effect in daylight. The complex stoichiometry was determined using a Job's plot and it was found to be 2 : 1 (ligand/metal). The binding constant was calculated with the Benesi-Hildebrand equation to be 1.39 × 1010 M-1 and the detection limit was 1.28 μM (LOD = 3α/slope, α is the standard deviation) for Cu(ii). The data proved that the binding between N-Bodipy and Cu(ii) is chemically reversible.

Optical Sensing of Copper and Its Removal by Different Environmental Technologies

“…The authors also reported theoretical calculations and biological studies and the practical applicability of the sensors in the living cell. Baslak et al . developed a Cu (II) ion sensor in acetonitrile/water.…”

Colorimetric Detection of Copper(II) Ions Using Schiff‐Base Derivatives

“…[25][26][27] Recently, a few colorimetric sensors for Cu 2 + have been also reported. [28][29] These sensors also suffer from long response time, poor selectivity, complex organic synthesis, and poor detection limits. [30] Nowadays, Schiff base derivatives are increasingly used as colorimetric sensors due to their simple synthesis steps and high selectivity.…”

“…But, many have some limitations, such as having a weak detection limit and complex synthesis steps . Recently, a few colorimetric sensors for Cu 2+ have been also reported . These sensors also suffer from long response time, poor selectivity, complex organic synthesis, and poor detection limits .…”

Coumarin-Based Dual Chemosensor for Colorimetric and Fluorescent Detection of Cu2+in Water Media

“… 22 − 24 So far, many fluorescent probes for Cu 2+ ions have been reported. The development of new fluorescent probes is, however, still being concerned due to the limitations of reported probes such as low sensitivity and selectivity, 25 , 26 a narrow range of pH, 20 , 27 − 29 working in solutions with a high proportion of organic solvents, 26 , 30 and excitation wavelength in the ultraviolet region. 26 , 28 , 31 , 32 These limitations reduce the application of probes to monitor Cu 2+ ions in living cells.…”