A new selective turn-on fluorogenic dipodal-cobalt(II) ensemble probe for nitrite ion detection and live cell imaging

A new dipodal-triazole-Co2+-ensemble with a ligand containing quinoline moiety was designed and synthesized as a highly sensitive fluorescent sensor for nitrite in aqueous media. Based on in situ-formed Co2+–DTQ (Co2+ chelated dipodal of triazole-quinoline) ensembles having the specific binding affinity for nitrite anions over other anions, this sensory system allows rapid recognition and quantitative detection of nitrite in neutral aqueous media in an ‘off–on’ fashion. To confirm the suitability of DTQ for biological applications, we also employed it for the fluorescence detection of the changes of intracellular NO 2 - in three different species of cultured cells in the presence of nitrite ions.