Triarylborane substituted naphthalimide as a fluoride and cyanide ion sensor

Abstract

Triarylborane substituted naphthalimide 3 was designed and synthesized by the Sonogashira cross-coupling reaction. The electronic absorption and emission spectra of the triarylborane naphthalimide 3 show red shifted absorption and emission as compared to 4-bromonaphthalimide 2. The sensing behaviour of 3 was studied for different anions. The triarylborane naphthalimide 3 selectively detects F⁻ and CN⁻ ions in the presence of Cl⁻, Br⁻, I⁻ and NO₂⁻ ions. The effect of F⁻ and CN⁻ ions on the structure of 3 was studied by performing DFT calculations. The theoretical calculations show good agreement with the experimental results. The detection limits for F⁻ and CN⁻ were found to be 2.01 × 10⁻¹⁰ M and 3.94 × 10⁻¹⁰ M respectively.