A near-infrared and ratiometric fluorescent chemosensor for palladium. 
A near-infrared chemosensor for palladium based on the Tsuji-Trost reaction was developed.  It displayed specific and ratiometric fluorescent responses toward palladium with a distinct color change from green to blue in aqueous media.  PEG400 was employed as the reducing agent and palladium ligand instead of water-insoluble triphenylphosphine.  The chemosensor's bioimaging potential was demonstrated by in vitro and in vivo experiments.