Visual Simultaneous Detection and Real-Time Monitoring of Cadmium Ions Based on Conjugated Polydiacetylenes

We
prepared the monomer PCDA-HP composed of 5-hydroxy-N1,N3-bis­(pyridin-2-ylmethyl)­isophthalamide
(HP) as a cadmium ion tweezer and then polymerized them
to form a polydiacetylene (PDA)-based sensor (PDA-HP),
which displayed selective and sensitive colorimetric and fluorometric
change upon addition of a cadmium ion (Cd2+) at both pH
7.4 and 6.8. The PDA-HP polymer was highly selective
for Cd2+ over other metal ions with colorimetric change.
In addition, the PDA-HP chemosensor also showed a red
fluorescence change in the presence of Cd2+ at both pH
7.4 and 6.8. Naked-eye detection of Cd2+ was accomplished
in an aqueous solution through a PDA-based sensor system. Finally,
the lowest energy structure of an HP chelator was obtained by the
crystal structure and density functional theory (DFT) calculations.