A Fluorescent Turn-On Sensor Toward Multiple Heavy Metal Ions Based on Meso-anisole Modified BODIPY Scaffold

A fluorescent turn-on sensor (BOPA) was configured by anchoring bis(pyridin-2-ylmethyl)-amine (DPA) unit to the BODIPY scaffold. It exhibits highly sensitivity and selectivity towards Pb2+, Ba2+, Cr3+, Cd2+, Hg2+, Zn2+ against the competent metal ions. Job’s plot analysis supports the 1:1 stoichiometry of BOPA and metal ions. And linear relationship between fluorescence intensity and concentration of Zn2+ (representative metal ion) was observed over the range 0 ~ 20 μM Zn2+. The limit detection of BOPA in recognition of Pb2+, Ba2+, Cr3+, Cd2+, Hg2+, Zn2+ was ranged from 15.99 to 43.57 nM. Photo induced transfer (PET) in the excited state of BOPA determines the emission “off/on”. Coordination of metal ions by DPA significantly weakened the electron-donating ability of nitrogen atom and inhibits the PET, recovering emission of BODIPY. In addition, the attachment of anisole at meso-position of BODIPY finely modulated the recognition of metal ions category.