A novel acylhydrazone-based derivative as dual-mode chemosensor for Al3+, Zn2+ and Fe3+ and its applications in cell imaging

Publication date: June 2017
Source:Sensors and Actuators B: Chemical, Volume 244
Author(s): Zhuang Liao, Yang Liu, Su-Fang Han, Dan Wang, Jian-Quan Zheng, Xiang-Jun Zheng, Lin-Pei Jin
An acylhydrazone-based derivative, 3-hydroxy-N'-(2-hydroxy-1-naphthalene methylene)-2-naphthalene hydrazide (H3L), was synthesized and characterized by elemental analyses, IR, ¹H NMR and mass spectrum. H3L is non-fluorescent in DMSO. But the fluorescence emission is enhanced obviously via the formation of aggregates in DMSO/H2O mixture. The formed aggregates were confirmed by DLS and SEM. H3L is an aggregation-induced emission (AIE)-active fluorophore. H3L can act as a fluorescence sensor for Al³⁺ and Zn²⁺ in DMSO/H2O (v/v, 9/1) and THF/H2O (v/v, 999/1), respectively. And H3L is also a naked-eye probe for Fe³⁺ in DMSO/H2O (v/v, 9/1). The binding stoichiometry of H3L to both Al³⁺ and Zn²⁺ is 1:1, but that to Fe³⁺ is 2:1. The metal complex species formed in the detection procedure are deduced by Job plot, spectroscopic titrations and ESI–MS to be [AlL(DMSO)2], [Zn(HL)(H2O)] and [Fe(HL)(H2L)]. The detection limit is as low as 3.66μM for Al³⁺, 1.01μM for Zn²⁺ and 0.34μM for Fe³⁺. H3L can also be used to detect intracellular Al³⁺ and Zn²⁺. The sensing event might be attributed to a combinational effect of excited state intramolecular proton transfer (ESIPT) and chelation-enhanced fluorescence (CHEF) mechanism for selective detection of Al³⁺ and Zn²⁺ ions, and ligand-metal charge transfer (LMCT) mechanism for Fe³⁺ ion.

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