Arene-based fluorescent probes for the selective detection of iron

Abstract

Pyridine-2,6-dicarboxamide based probes containing phenyl (L1), naphthyl (L2) and anthracenyl (L3) groups have been synthesized and screened towards Na⁺, Mg²⁺, Ca²⁺, Cr³⁺, Mn²⁺, Mn³⁺, Fe²⁺, Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Hg²⁺, Cd²⁺ and Pb²⁺ ions. Probes L2 and L3 exhibited remarkable sensing for Fe²⁺ and Fe³⁺ ions with L3 being particularly selective. Collective studies comprising of Job's plot, Benesi–Hildebrand fitting, Stern–Volmer plot and detection limit display notable sensing ability of probe L3 for Fe³⁺ as compared to Fe²⁺ ion. Competitive binding studies in presence of other metal ions further illustrated the high efficiency of L3. The probe L3 binds to Fe³⁺ ion by forming a 1 : 1 complex with the apparent association constant (K_a) of 3.31 × 10³ M⁻¹. L3–Fe³⁺ system is shown to have potential applications in logic gate and cell imaging.