Colorimetric and Fluorimetric Multiple Metal Ion Sensing Using Naphthalene-Based Schiff Base

Abstract

A novel Schiff base ligand functionalized with a naphthalene moiety has been developed as colorimetric and fluorimetric sensor for the selective detection of multiple metal ions. The coordination of four metal ions (Fe²⁺, Fe³⁺, Co²⁺, and Ni²⁺) induces an individual color change in solution, while fluorescence is emitted upon the addition of seven other metal ions (Mg²⁺, Ca²⁺, Cd²⁺, Zn²⁺, Al³⁺, Ga³⁺, and In³⁺). The reliability of the chemosensor was evaluated through competition experiments with a panoply of different cations. The nature of the solvent was revealed to have an impact on the fluorescence properties but not on color changes, whereas the type of counterion did not influence the colorimetric and fluorimetric detection.