A 'turn-off' fluorescence sensor for selective Hg(II) based on phenothiazine derivative

Given how crucial it is to preserve a human-safe and sustainable environment, the rapid discovery of possibly lethal heavy metals such as Hg(II) has drawn much attention in recent years. A novel sensor, known as (E)-2-((10-octyl-10H-phenothiazin-3-yl)methylene)hydrazine-1-carbothioamide (PTZHC), was synthesized as a fluorescence 'on-off' sensor for Hg ions. Coordination alters organic molecule electron densities, quenching the fluorescence intensity. PTZHC was described completely with the help of FTIR and H-NMR spectrum studies. The Hg ion was successfully detected using the PTZHC sensor even when there were other metal ions present. The limit of the detection was estimated to be 2.5 × 10 M and the Job's plot examination implied that PTZHC was bound to Hg with a simple 1:1 stoichiometry in s CH CN/H O (9:1, v/v) suspension. To further cast light on the bridged effect on geometric and optoelectronic characteristics, time-dependent density functional theory (TD-DFT) at the B3LYP/6-31G(d) level and DFT were both examined.