Turn‐On Solid‐State Fluorescent Determination of Zinc Ion by Quinoline‐Based Covalent Organic Framework

A new quinoline‐based COF (covalent organic framework), obtained by Povarov reaction, containing 2,6‐diisopropylphenyl moieties as substituents over the heterocyclic ring is described for detecting Zn 2+ in aqueous solution. The introduction of the mentioned bulky phenyl rings into the network favors an increase of the distance between the reticular sheets and their arrangement, obtaining a new material with an alternating AB type stacking. The new material exhibits good selectivity to detect Zn 2+ by fluorescence emission in aqueous solutions up to a concentration of 1.2 × 10 −4 m of the metal ion. In order to have a deeper insight into the interaction between the COF and the zinc cation, a thorough spectroscopical, microscopical, and theoretical study is also presented and discussed in this communication.