A new lawsone azo-dye for optical sensing of Fe3+ and Cu2+ and their DFT study

A new lawsone-based azo-dye 2-hydroxy-3-((pyridin-2-ylmethyl)diazenyl) naphthalene-1,4-dione (1) was synthesized and applied for sensing of metal ions. Receptor 1 showed selective fluorescent and colorimetric response for the detection of Cu2+ and Fe3+ over other tested metal ions. The fluorescence intensity of 1 was significantly quenched allowing detection of Fe3+ and Cu2+ down to 0.61 and 6.06 mu M, respectively. The binding has been established by fluorescence spectroscopic method. Receptor 1 provided a 1 : 1 binding scaffold for recognition of Fe3+ and Cu2+ ions with the association constant of 3.33 x 10(6) and 3.33 x 10(5) M-1, respectively. The B3LYP/6-31G/LANL2DZ method was employed for the optimization of 1 and 1.Fe3+ and 1.Cu2+. [GRAPHICS]