Selective detection of Cu2+ by benzothiazole-based colorimetric chemosensor: a DFT study

An effectively selective colorimetric chemosensor BTV (2-methoxy-6-((E)-(((E)-3-methylbenzo[d]thiazol-2(3H)-ylidene)hydrazono)methyl)phenol) was synthesized for detecting Cu2+. The BTV having benzothiazole group showed a bathochromic shift (150 nm) with an explicit color variation from colorless to pink toward Cu2+. The BTV could detect Cu2+ down to 0.37 mu M in solution. The binding ratio of BTV and Cu2+ was determined to be a 1:2 by Job plot and ESI-MS. Sensor BTV could distinctly sense Cu2+ without interference from other cations and distinguish it from diverse metal ions through the test strip. The sensing process of Cu2+ by BTV was presented by UV-visible titration, Job plot, H-1 NMR titration, DFT calculation, FT-IR and ESI-MS.