A Fluorescent and Colorimetric Chemosensor Detecting Pd²⁺ Based on Chalcone Structure with Triphenylamine

A fluorometric and colorimetric chemosensor DiPP ((E)-3-(4-(diphenylamino)phenyl)-1-(pyridin-2-yl)prop-2-en-1-one) based on chalcone structure with a triphenylamine group was synthesized. Sensor DiPP detected Pd²⁺ with fluorescence turn-off and via colorimetry variation of yellow to purple. The binding ratio of DiPP to Pd²⁺ turned out to be 1 : 1. Detection limits for Pd²⁺ by DiPP were analyzed to be 0.67 µM and 0.80 µM through the fluorescent and colorimetric methods. Additionally, the fluorescent and colorimetric test strips were applied for probing Pd²⁺ and displayed that DiPP could obviously discriminate Pd²⁺ from other metals. The binding feature of DiPP to Pd²⁺ was presented by ESI-mass, Job plot, NMR titration, ESI-mass, and DFT calculations.