Dual functional turn-on non-toxic chemosensor for highly selective and sensitive visual detection of Mg2+ and Zn2+: solvent-controlled recognition effect and bio-imaging application
A new dual functional turn-on chemosensor, (2-hydroxy-5-methyl-1,3-phenylene)bis(methanylylidene)bis(isoquinoline-1-carbohydrazide) (HL), has been developed, which could highly selectively discriminate Mg2+ and Zn2+ in different solvent systems. The chemosensor HL exhibits rapid visual turn-on fluorescent enhancing recognition toward Mg2+/Zn2+, which are not interfered by other cations, especially for respective congeners Ca2+/Cd2+. The remarkable fluorescent enhancement (71-fold or 11-fold) were observed after adding Mg2+ in acetonitrile or Zn2+ in DMF-H2O solvent systems. Additionally such a solvent medium-controlled platform could achieve quantitative determination of Mg2+ and Zn2+ quantitation with low detection limits of 2.97 × 10–8 M and 3.07 × 10–7 M, respectively. Further the turn-on fluorescent sensing mechanism is also investigated by 1H NMR spectra, FT-IR and ESI-MS spectra. Density functional theory (DFT) calculations derive optimized geometries of HL and its complexes. Notably, non-toxic HL also can be successfully applied as a visual probe for practical determination of Mg2+/Zn2+ in MCF-7 cells, Zebrafish larvae, syrup and water samples, which might provide extensive application in biological and medicine field.