Ratiometric fluorescence sensing of hypochlorite ion by dansyl hydrazine-Spectroscopic and TD-DFT studies

Probe dansyl hydrazine ( DH ) exhibits highly selective and sensitive fluorescence detection properties to-wards hypochlorite (OCl-) ions in DMSO and aq. DMSO media. The probe comprises a fluorophore N,N-dimethylnaphthalene unit and an electron-withdrawing -SO2NHNH2 moiety attached to it. Titration of OCl- ions with DH caused C-S bond cleavage reaction that enhanced the fluorescence of DH with a blue shift. 1 H NMR and HRMS spectral techniques were used to confirm the OCl-ion-triggered C-S bond cleav-age mechanism. Based on DH's significant fluorescence enhancement response to OCl- ions, the detec-tion limit was estimated as low as 18 mu M. Moreover, computational density functional theory (DFT) and time-dependant density functional theory (TD-DFT) calculations provided more insight into the probe's absorption and emission spectral properties before and after the addition of OCl- ions. Additionally, the probe DH would be a potential tool for detecting OCl- ion concentration in bleaching powder.(c) 2022 Elsevier B.V. All rights reserved.