Perylenebisimide-Based Colorimetric and Fluorescent Sensors for Selective Detection of Anions

A new type of perylenebisimide-based imidazolium chemosensor was synthesized for selective recognition of anions. Imidazolium-anchored receptor PBI-1 showed high binding affinity to F- due to the role of the phenolic hydroxyl group as an additional binding site. The hydroxyl-protected receptor PBI-2 could serve as highly selective and sensitive colorimetric and fluorometric sensor for H2PO4-. The study indicated that the C2-H of the imidazolium ring played an essential role in the anion recognition via synergistic effects of multiple hydrogen-bonding and electrostatic interactions. In addition, it was noteworthy that the phenolic hydroxy of the receptor was not indispensable for binding H2PO4 -, but very pivotal for binding F-.