A new highly Zn2+-selective and "off-on" fluorescent chemosensor based on the pyrene group

In this work, an "off-on" type zinc ion fluorescent chemosensor H2L with pyrene as a fluorophore was investigated. The chemosensor H2L demonstrates a Zn2+-specific emission enhancement linearly with a 1 : 1 binding ratio even in the presence of a wide range of competing metal ions. This may be correlated with the efficient Zn2+ binding of H2L, which promotes a good chelation-enhanced fluorescence (CHEF) effect and prevents the photoinduced electron transfer (PET) effect, and C=N isomerization is inhibited. Importantly, the fabricated chemosensor can selectively distinguish Zn2+ from Cd2+. And the recognition behaviour has been proved experimentally and computationally.