Schiff base-functionalized silatrane-based receptor as a potential chemo-sensor for the detection of Al3+ ions

Abstract

Excess Al³⁺ ions are considered toxic to living organisms. Keeping the harmful effects of excess Al³⁺ metal ions in mind, a new Schiff base = functionalized silatrane as a potential chemo-sensor for the recognition of aluminium metal ions with high selectivity and specificity has been designed and well characterized using various characterization techniques such as IR, ¹H NMR, ¹³C NMR, TGA, and mass spectroscopy. The chemo-sensing properties were studied using ultraviolet and fluorescence spectroscopy. The absorption spectrum of the synthesized receptor was changed only by the addition of Al³⁺ ions, while other ions showed negligible changes. The 1 : 1 stoichiometric ratio of the chemo-sensor 4b with Al³⁺ was confirmed by Job's plot and linearity in the B–H plot. The limit of detection observed for Al³⁺ ions was 2.273 × 10⁻⁷ M and 9.8 × 10⁻⁹ M from ultraviolet and fluorescence spectroscopy, respectively. The binding constant from the B–H plot and the Stern–Volmer quenching constant were found to be 0.2279 × 10⁶ M⁻¹ and 2.7 × 10⁶ M⁻¹, respectively. These results explain the potential chemo-selectivity of the receptor 4b towards Al³⁺ metal ions, which may be useful for biological and industrial purposes.