Designing of efficient two-armed colorimetric and fluorescent indole appended organosilicon sensors for the detection of Al(III) ions: Implication as paper-based sensor

Spectrochim Acta A Mol Biomol Spectrosc. 2023 Dec 5:302:123015. doi: 10.1016/j.saa.2023.123015. Epub 2023 Jun 15.

Abstract

Metal ions have significant roles in diagnosis, industry, human health, and the environment. To design and develop new lucid molecular receptors for the selective detection of metal ions is important for environmental and medical applications. In the present work, two-armed indole appended Schiff bases conjoined with 1,2,3-Triazole bis-organosilane and bis-organosilatrane skelton sensors for naked eye colorimetric and fluorescent detection sensors for Al(III) are developed. The introduction of Al(III) in sensor 4 and 5 show red shift in UV-visible spectra, changes in fluorescence spectra and immediate color change from colorless to dark yellow. Furthermore, the pH and time response studies were explored for both sensors 4 & 5. The sensors 4 and 5 exhibited significantly low detection limit (LOD) in nano-molar range 1.41 × 10-9 M and 0.17 × 10-9 M respectively from emission titration. The LOD form absorption titration was found to be 0.6 × 10-7 M for sensor 4 and 0.22 × 10-7 M for sensor 5. In addition, the sensing model is developed as paper based sensor for its practical applicability. The theoretical calculations were performed on Gaussian 03 program by relaxing the structures using Density functional theory.

Keywords: Al(III); Colorimetric; Fluorescent; Organosilicon; Paper-based sensor; Sensor.