A Phenazine based colorimetric and fluorescent chemosensor for sequential detection of Ag+ and I− in aqueous media

A new colorimetric and fluorescent probe MNTPZ based on 1H-imidazo[4,5-b]phenazine derivative has been designed and synthesized for successive detection of Ag(+) and I(-) . The probe MNTPZ shows selective colorimetric response by a change in color from yellow to orange and "turn-off" fluorometric response upon binding with Ag(+) in DMSO: Water (pH = 7, 1:1, v/v) over other cations. The binding mode of probe MNTPZ to Ag(+) was studied by Job's plot, (1) H NMR studies, FT-IR spectroscopy and DFT calculations. Moreover, the situ generated probe MNTPZ+ Ag(+) complex acted as an efficient fluorometric "turn-on" probe for I(-) via Ag(+) displacement approach. The detection limit of probe MNTPZ for Ag(+) and the resultant complex probe MNTPZ+ Ag(+) for I(-) were determined to be 1.36 mumol/L and 1.03 mumol/L respectively. Notably, the developed probe was successfully used for quantitative determination of I(-) in real samples with satisfactory results.