A highly selective "turn-on" fluorescent chemosensor based on hydroxy pyrene-hydrazone derivative for Zn 2+

Abstract

A new hydroxypyrene-based sensor 1 was designed and synthesized as a Zn 2+ selective colorimetric and fluorescent chemosensor. This chemosensor showed a new UV-vis absorption peak (λ max = 498 nm) with Zn 2+, which can be attributed to an internal charge transfer (ICT) mechanism. In addition, Zn 2+ induced a highly selective "turn-on" fluorescence enhancement at long wavelength (λ max = 588 nm) in a buffered system. A significant fluorescence enhancement was observed upon the addition of Zn 2+. The combination of two phenol groups on the pyrene and phenyl moieties as well as a conjugated hydrazone group can generate a binding pocket for Zn 2+. These results also demonstrate that 1-hydroxypyrene-2-carboaldehyde can be a unique platform to introduce various ligands for the colorimetric and fluorescent recognition of metal ions. © 2012 Elsevier Ltd. All rights reserved.