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

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