Polydiacetylenes Functionalized with Chelidamic Acid and 2,2'‐Dipicolylamine for Colorimetric Responses to Cadmium Ions

A novel polydiacetylene‐linked ligand derived from the reaction between chelidamic acid and bis(pyridin‐2‐ylmethyl)amine (PDA‐CB) showed excellent selectivity and sensitivity for Cd2+ ions compared with other metal ions, including Zn2+. An obvious color change between PDA‐CB and PDA‐CB + Cd2+ is clearly visible to the naked eye. The Cd2+‐responsive color change of PDA‐CB is attributed to the coordination between Cd2+ and CB ligand units and has been characterized by 1H NMR titration. A novel polydiacetylene‐linked ligand derived from the reaction between chelidamic acid and bis(pyridin‐2‐ylmethyl)amine (PDA‐CB) showed excellent selectivity and sensitivity for Cd2+ ions compared with other metal ions, including Zn2+.