Fluorescent sensor based on triphenylamine for Zn2+ with high selectivity and imaging in living cells

Abstract

It is of great importance to design a fluorescent sensor with high selectivity, sensitivity and large Stokes shift to zinc detection for environmental water sample and in vivo. Herein, A novel Zn2+ fluorescent sensor with larger Stokes shift (110 nm) 1-((5-(4-(diphenylamino)phenyl)pyridine-2-imino)methyl)naphthalene-2-ol (abbr. TPA-PN) was designed and synthesized. In DMF-H2O (V: V = 1: 1, pH = 7.0) solution, it could achieve high selectivity and sensitivity to Zn2+, there was a linear responsive range of 0–20 μM of concentration of Zn2+ ions for the sensor, the detection limit was as low as 19.134 nM and the binding constant was calculated to be 3.24 × 104 M−1. The species of TPA-PN and zinc were clarified at different pH. Besides, the interaction properties and fluorescence mechanism were demonstrated by the species theory, density functional theory (DFT) calculation, 1H NMR titration, FT-IR and MS. Most importantly, it provided a new real-time, on-site method and showed excellent potential in-vivo imaging ability.