A Near-Infrared Fluorescent Probe with 2-Hydroxy-N,N-dimethylbenzylamine as a New Recognition Fragment for Pd2+ Detection and Bioimaging

A near-infrared fluorescent probe DHDM bearing isophorone skeleton and 2-hydroxy-N,N-dimethylbenzylamine has been rationally designed and synthesized. DHDM showed excellent Pd2+ specificity with a low detection limit of 53 nmol/L and a large Stokes shift (220 nm). The fluorescence intensity at 660 nm was linear to Pd2+ concentrations in a wide range (0 similar to 70 mu mol/L). Additionally, a possible sensing mechanism was proposed based on the results of the mass spectroscopy, infrared spectrum, a comparative experiment and density functional theory (DFT) calculations. Finally, DHDM was further successfully used to image Pd2+ in live cells, suggesting its potential applications in biological systems. The design strategy based on 2-hydroxy-N,N-dimethylbenzylamine or one of its analogues as a new recognition fragment will inspire researchers to construct privileged fluorescence probes in the future.