Inserting auxiliary ligand to construct a Cd(II)-based salamo-like coordination polymer as bifunctional chemosensor for detecting picric acid and S 2−

A tailored Cd(II) coordination polymer [Cd(HL) 2 (1,4-pbyb)] n ( Cd(II)-CP ), has been synthesized successfully by using the host ligand H 2 L (4‑chloro-4ʹ‑bromo-6‑bromo-6ʹ‑tert‑butyl‑2,2ʹ-[ ethylenedioxybis ( nitrilomethylidyne )]diphenol) and auxiliary ligand 1,4-di(pyridin-4-yl)benzene (1,4-pbyb) under the room temperature volatilization method. Single crystal X-ray diffraction experiment showed that Cd(II) atoms possess a slightly twisted hexa-coordinated octahedron configuration and Cd(II)-CP forms an infinite 1D zigzag-like chain configuration. The structural diversity of Cd(II)-CP is mainly attributed to the introduction of auxiliary ligand. The Cd(II)-CP is a highly selective and sensitive luminescent bifunctional chemosensor toward nitroaromatic compounds (NACs) and anions, which exhibits turn-off fluorescence effect on picric acid (PA) and turn-on fluorescence effect for sulfide ions (S 2− ). The sensing mechanisms were also carefully investigated. This study provides new conceptions for the design of CPs for detecting pollutants from surroundings, potentially mitigating health risks to humans and natural ecosystems.