Fatty-chain-switched cationic fluorescent probe for SCN−, PF6−, and HSO3− recognition in water: Study of anion selectivity and sensitivity

In this work, a water-soluble cationic fluorescent probe with AIE features exhibited unique sensing of charge-diffuse anions, namely, SCN − , PF 6 − , and HSO 3 − via ionic interactions and the subtle cooperation of the tunable hydrophobicity . The effect of the fatty chain length on the cationic probes indicated that the sensitivity and selectivity of the probes can be rationally improved by switching their aggregation tendency (hydrophobic effect) in water or by integrating them in the form of a fluorescence chemosensor array. SEM images suggest that different morphologies were formed in the anion-recognition-triggered self-assemblies of the probes, which can be attributed to the different anion molecular geometries. Additionally, the precipitation of the SCN − -recognition complex provided a new insight to the separation of anions from an aqueous environment .