Arene-based fluorescent probes for the selective detection of iron†
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 (Ka) of 3.31 × 103 M−1. L3–Fe3+ system is shown to have potential applications in logic gate and cell imaging.