Hydroxyl phenyl imino modified phenanthro[9,10-d] imidazole: An AIEE-active sensor for determination of Cu2+ in water samples and subsequent “turn-on” recognition of Cr3+ with logic gates

Abstract A 2-hydroxyl phenyl imino modified phenanthro[9,10- d ]imidazole probe ( PPIP ) was synthesized and its aggregation-induced emission enhancement (AIEE) phenomenon in aqueous medium was characterized by the Tyndall phenomena, morphologies of scanning electron microphotograph (SEM) as well as the enhanced fluorescence intensities. The AIEE-active PPIP in aggregated states exhibited a sensitive detection for Cu 2+ along with the elimination of fluorescence intensity; subsequently, in situ PPIP- Cu 2+ complex showed selective fluorescence “turn-on” for Cr 3+ , providing a potential platform for tandem recognition of Cu 2+ and Cr 3+ . The 1:1 M ratio between PPIP and Cu 2+ was confirmed by Job's plot, 1 H NMR spectra, mass spectra and density functional theory (DFT) calculations. The detection limits for Cu 2+ and Cr 3+ were 4.127 × 10 −2  μM and 9.404 × 10 −1  μM, respectively. Moreover, this successive recognition could be utilized to construct the molecular logic gates by the fluorescence changes. In addition, PPIP was successfully employed for quantitative detecting Cu 2+ in real water samples with satisfactory results.