A highly selective chemosensor for Al(III) and Zn(II) and its coordination with metal ions

Inorg Chem. 2014 Mar 17;53(6):3012-21. doi: 10.1021/ic402811x. Epub 2014 Feb 26.

Abstract

This paper reports a fluorescence chemosensor, N-(benzimidazol-2-yl)salicylaldimine (H2L), for Zn(II) and Al(III) ions. H2L has high selectivity for Al(III) in dimethyl sulfoxide (DMSO) and for Zn(II) in N,N-dimethylformamide (DMF). In methanol, Zn(II) and Al(III) could also be distinguished by H2L with different excitation wavelengths. The fluorescent species [Zn(HL)(H2O)(CH3OH)](+), [Zn(HL)(H2O)(DMF)](+), [Al(HL)2(OH)(H2O)], and [Al(HL)(OH)2(H2O)(DMSO)] formed in solution were established by a combination of experimental and theoretical methods, including Job's plot, (1)H NMR titration, electrospray inonization mass spectrometry (ESI-MS), and B3LYP-SCRF/6-31(d) and TD-B3LYP-SCRF/6-31G* density functional theory methods. The results show that Zn(II) and Al(III) are all coordinated to the imine nitrogen atom and the hydroxyl oxygen atom from H2L, which is the same as the M(2+) ions in the obtained mononuclear complexes [M(HL)2(CH3OH)2] (where M = Cd, Ni, Co, and Mg). The detection limits of H2L for Zn(II) were 5.98 μM in methanol and 5.76 μM in DMF, while the detection limits of H2L for Al(III) were 3.3 μM in methanol and 5.25 μM in DMSO. Furthermore, it is also confirmed that H2L has low toxicity for HeLa cells and could be used to detect Zn(II) and Al(III) ions in living cells by bioimaging.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aluminum / chemistry*
  • Crystallography, X-Ray
  • Proton Magnetic Resonance Spectroscopy
  • Spectrometry, Mass, Electrospray Ionization
  • Zinc / chemistry*

Substances

  • Aluminum
  • Zinc