Azophenyl appended Schiff base probe for colorimetric detection of Cu2+ in semi-aqueous medium and live cell imaging

A phenylazo appended ortho-vanillin Schiff base scaffold (HAZ) has been used for selective colorimetric sensing of Cu2+ in semi-aqueous medium (methanol-water, 1:1, v/v) in the presence of 16 cations and 20 anions, and the limit of detection is 1.8 x 10(-7) M. The structures of HAZ and Cu (II) complex, [Cu(AZ)(2)], have been characterised by spectroscopic data (UV-Vis, Fourier transform infrared and electron paramagnetic resonance) and established by the single crystal X-ray diffraction measurement. The Job's plot from the absorption studies has also confirmed the 1:2 stoichiometry of Cu2+:HAZ. The absorption spectrum of [Cu (AZ)(2)] has returned to the spectrum of HAZ on the addition of Na(2)EDTA solution which is again recovered upon the addition of Cu2+ solution. Discrete Fourier transform computations were carried out using the coordinates of the X-ray structures of the compounds, and the molecular functions were used to correlate the solution spectroscopic properties. In addition to this, the probe is treated on MDA-MB 231 breast cancer cells to check the cytotoxicity. The probe is used for the detection of trace quantity of Cu2+ in the cancer cell.