A multi-responsive cyanine-based colorimetric chemosensor containing dipicolylamine moieties for the detection of Zn(II) and Cu(II) ions

A cyanine-based chemosensor containing dipicolylamine moieties is reported and its structure is well-defined. Investigation on the optical property shows it is pH-independent. Acidic medium can induce the color change from azure to dark blue while it presents the green in the alkaline condition (pH 10) in comparison to the neutral condition. More, owing to the introduction of dipicolylamine units, this chemosensor can be used as a colorimetric indicator for Zn(II) and Cu(II) ions along with color change from green to bright blue. Especially, its copper complex has a capability of determining the sulfide anion (S2−) with high selectivity, and as a consequence, the color of solution turns back to the green. This work provides a promising indicator for the analysis of multi species.

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