Cyclic benzobisimidazolium derivative for the selective fluorescent recognition of HSO4- via a combination of C-H hydrogen bonds and charge interactions

In this study, a novel fluorescent cyclic benzobisimidazolium derivative was designed and prepared for the selective recognition of HSO4 . Pre-organization, neutral C-H hydrogen bonds and charge interactions play key roles in recognizing HSO4- in aqueous solution. Spectroscopic studies, including UV-vis and fluorescence, showed that this cyclic receptor exhibited high selectivity in response to HSO4-. X-Ray crystal data, NMR data and theoretical calculations are presented to explain its unique binding mode.