A dual-function probe based on naphthalene diimide for fluorescent recognition of Hg2+ and colorimetric detection of Cu2+.

The core-substituted naphthalene diimide ( NDI-6 ) as a dual-function probe was synthesized conveniently, which can monitor Hg 2+ by fluorescent response and serve as a naked-eye detector towards Cu 2+ . The strong red emission induced by the addition of Hg 2+ can be ascribed to the inhibition of the twisted intramolecular charge transfer (TICT) in the excited state, based on the experimental data and theory calculation. Meanwhile, NDI-6 could be used as a reversible fluorescent probe towards Hg 2+ with the aid of I − as test strips, which can be applied into the detection of real samples. [ABSTRACT FROM AUTHOR]