On/Off Fluorescent Chemosensor for Selective Detection of Divalent Iron and Copper Ions: Molecular Logic Operation and Protein Binding

[Image: see text] Here, naphthalene diamine-based β-diketone derivative (compound LH) was successfully used as a dual signaling probe for divalent cations, Fe(2+) and Cu(2+) ions, in bimodal methods (colorimetric and fluorometric). It showed fluorescent enhancement for Fe(2+) ion by photoinduced electron transfer mechanism and fluorescence quenching for Cu(2+) ion by charge-transfer process. Binding stoichiometry for [LH–(Fe(2+))(2)] and [LH–(Cu(2+))(2)] was found to be 1:2 by Job’s plot method and, the binding constants were calculated as 1.6638 × 10(10) and 9.22929 × 10(8) M(–1), respectively. Compound LH exhibited OR and XOR logic gate behavior with H(+), Fe(2+), and Cu(2+) as inputs. Further, the compound LH and bovine serum albumin binding interaction showed quenching of fluorescence by Förster resonance energy-transfer mechanism.