Development of red to blue emissive fluorescent materials for cyanide ion sensing and single-component inks in digital printing application

Abstract

The work designed and described here is for the effective recognition of cyanide ion. A novel core (PC) with coumarin moiety as a signaling unit and pyridinium as an acceptor unit and these moieties linked by π-conjugation. In which CN⁻ ion binds in the pyridine ring via nucleophilic addition and produces changes that are captured by different techniques to prove its sensing efficiency. The probe displays a visual color variation to pale orange from purple and also exhibits blue fluorescence from red fluorescence upon cyanide addition. The probe PC sensing ability towards CN⁻ ion has been confirmed by various spectral measurement. In UV–visible technique, a blue shift was observed by the probe with CN⁻ ion. In fluorescence measurements, a peak appeared at 704 nm, which corresponds to the probe encountering a peak enhancement with the added cyanide ion. The binding stoichiometric ratio among the probe and CN⁻ ion is to be 1:1 in jobs method. The probes detection limit and binding constant were calculated to be 0.39 nM and 7.07x10⁴ M. The probe is used as a single component ink and injected into a cartridge and printed on paper which is used as a tool to detect cyanide in water. Besides, the probe successfully senses cyanide ion in various water samples.