Imidazo-benzo-15-crown-5 ethers bearing arylthienyl and bithienyl moieties as novel fluorescent chemosensors for Pd2+ and Cu2+

Novel fluorescent ionophores bearing imidazo-arylthienyl or imidazo-bithienyl π-conjugated bridges functionalized with one or two fused benzo-15-crown-5 ethers as receptor units are reported. The sensing ability of the compounds in the presence of metallic cations (Li+, Na+, K+, Ca2+, Zn2+, Cu2+, Ni2+, Pd2+, and Hg2+) and fluoride ion was studied in MeCN/DMSO solutions by absorption and emission spectroscopy. The experimental results indicate that all compounds could act as selective fluorimetric sensors for Cu2+ and Pd2+ and also for the fluoride ion, in the case of the bis-substituted crown ether derivatives.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis of novel imidazo-benzo-15-crown-5 ethers bearing arylthienyl and bithienyl π-bridges. ► Characterization of the absorption and emission properties of imidazo-benzo-15-crown-5 ethers. ► Thienyl derivatives of benzo-15-crown-5 ethers as selective fluorescent chemosensors for Pd2+ and Cu2+. ► Bis-substituted imidazo-benzocrown ethers as selective fluorimetric sensors for the fluoride ion.