A pyrene based novel di-Schiff base colorimetric and turn-on fluorescent-chemosensor for selective and sensitive detection of Hg2+ ion: Biological, logic gate and real sample applications

Abstract

Following a simple synthetic process, a new pyrene derivative with a benzildihydrazone moiety has been synthesised and used for selective detection of Hg²⁺ across four distinct channels (colorimetric, absorption, emission, and bio-imaging). When Hg²⁺ was present, the chemosensor L exhibited a noticeable increase in fluorescence, changing colour from yellow to colourless, while other metal ions only caused slight variations in fluorescence intensity as well as colour. The fluorescent-based assay’s sensitivity for Hg²⁺ is 1.04 × 10⁻⁶ M and colorimetric detection limit is 7.83 × 10⁻⁶ M, which are significantly lower than the threshold specified in the World Health Organization’s (WHO) drinking water guidelines. The 1:1 stoichiometric complexation between L and Hg²⁺ is demonstrated by the Job plot, and the ESI-MS spectra data. L has practical applications in real sample analysis, molecular logic gate and biology. Confocal fluorescence microscopy imaging in MCF 7 and human lymphocyte cells (HLCs) showed that L could be used as an effective fluorescent probe for detecting Hg²⁺ in living cells. Moreover L may be employed as anticancer drug without causing any harmful consequences at the given concentrations and incubation duration. L has also real sample and logic gate application.