A Benzothiazole-Based Fluorescence Turn-on Sensor for Copper(II).

A new benzothiazole-based chemosensor BTN (1-((Z)-(((E)-3-methylbenzo[d]thiazol-2(3H)-ylidene)hydrazono)methyl)naphthalen-2-ol) was synthesized for the detection of Cu. BTN could detect Cu with "off-on" fluorescent response from colorless to yellow irrespective of presence of other cations. Limit of detection for Cu was determined to be 3.3 μM. Binding ratio of BTN and Cu turned out to be a 1:1 with the analysis of Job plot and ESI-MS. Sensing feature of Cu by BTN was explained with theoretical calculations, which might be owing to internal charge transfer and chelation-enhanced fluorescence processes.