A novel anthracene functionalized dibenzoxanthene fluorophore for copper (II) sensing

Dibenzoxanthene derivatives are widely used in metal ion sensing applications. Especially, fluorescent dibenzoxanthene derivatives are potential candidate to sense metal ions in various solvent systems. However, most of the studies are focused on either metal sensing in aqueous solutions, or sensing of the extremely toxic metal ions, such as Pb²⁺ and Hg²⁺. In this study, a novel benzyl functionalized dibenzoxanthene derivative and a novel fluorescent anthracene functionalized dibenzoxanthene derivative were synthesized to sense metal ions in polar aprotic solvent systems by using UV–Vis spectroscopy and Fluorescence spectroscopy. As benzyl-dibenzoxanthene was sensitive to multiple metal ions (Pb²⁺, Co²⁺, and Cu²⁺), novel anthracenyl-dibenzoxanthene was only sensitive to Cu²⁺ with the binding capacity of one anthracenyl-dibenzoxanthene to three Cu²⁺ ions, thus the copper sensitivity was increased. The binding affinity of dibenzoxanthene derivatives with Cu²⁺ has been analyzed by ¹H NMR and High-resolution XPS.