Naphthylimide Chemosensor Based on Anion−π Interactions: A Promising Tool for Environmental Monitoring

In the domain of environmental monitoring, chemosensors
play a
pivotal role, particularly in the detection of ions such as fluoride.
Although this element is beneficial in controlled doses, it menaces
human health because it can attack tooth enamel in high concentrations.
Our research group has developed a selective chemosensor for fluoride
ions based on a naphthylimide derivative. This study employed a multifaceted
approach involving ultraviolet-visible (UV–vis), fluorescence,
and NMR spectroscopic techniques, complemented by theoretical calculations,
to elucidate the interaction. The employment of UV–vis methods
revealed a K11 value of 2.0 × 104 mol dm–3 for the chemosensor, indicating
its notable stability toward fluoride. A critical aspect of the probe’s
functionality is its anion−π interaction mechanism with
the analyte, a finding substantiated by 1H NMR titrations.
These titrations demonstrated that the primary interaction occurred
with the aromatic rings of the benzene moiety rather than with the
N–H group. Theoretical calculations corroborate these findings
and highlight the viability of anion−π interactions.
This chemosensor boasts numerous advantages, including cost-effectiveness,
ease of use, and high selectivity for fluoride. Consequently, they
have emerged as promising tools for environmental and analytical applications.