Highly selective fluorescent recognition of Zn2+ based on naphthalene macrocyclic derivative

A new macrocyclic chemosensor containing two naphthalene fluorophores has been synthesized. The fluorescent properties of this receptor has been studied in the presence of various metal ions such as Na+, Ag+, Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+ and Pb2+. When increasing concentrations of Zn2+ ions were introduced, the emission of L was drastically increased (EFE = 4.34). This special change was not observed when other metal ions were used; such highly selective fluorescent response indicates that this receptor can easily discriminate Zn2+ ions from other similar species. Model calculations at DFT level further suggest the possible interaction mode, and relatively steric position between the host and guest also influence the optical response.

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► A macrocyclic chemosensor (L) bearing the two naphthalene fluorophores was synthesized.
► L exhibits highly sensitive toward Zn2+ over other cations tested.
► A full minimization of the structure of macrocycle L and [ZnL]2+ were performed.