A novel phthalazine based highly selective chromogenic and fluorogenic chemosensor for Co2+ in semi-aqueous medium: application in cancer cell imaging†

Abstract

A new phthalazine based chemosensor 3 was developed for the highly selective and sensitive detection of Co2+ in the mixed solvent system, CH3CN–H2O (1[thin space (1/6-em)]:[thin space (1/6-em)]1, v/v). In the presence of Co2+, the colour of the solution 3 changed from yellow to green; the absorption maxima of 3 was red-shifted from 383 nm to 435 nm, and the fluorescence of 3 at 550 nm was significantly enhanced. The sensor 3 showed a detection limit down to 25 nM by forming a complex species with Co2+ in 1[thin space (1/6-em)]:[thin space (1/6-em)]1 stoichiometry. Furthermore, by means of confocal laser scanning microscopy experiments, it has demonstrated that it can be used as a fluorescent probe for monitoring Co2+ in living cells.