A veratraldehyde-appended organosilicon probe and its hybrid silica nanoparticles as a dual chemosensor for colorimetric and fluorimetric detection of Cu2+ and Fe3+ ions

This article highlights the design and synthesis of the Schiff bases of veratraldehyde-based organo-silatranes and organosilocanes (3a-3c), which were meticulously characterized with the aid of nuclear magnetic resonance (NMR, H-1 and C-13) and mass spectroscopy techniques. Moreover, compound 3a was fabricated over silica nanoparticles by a one-pot method, which was authenticated by infrared (IR) spectroscopy, X-ray diffractometry (XRD), energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and field emission scanning electron microscopy (FE-SEM) analysis. The colorimetric and fluorimetric detection of 3a and its hybrid silica nanoparticles (V-NPs) revealed their significant sensing ability towards Cu2+ and Fe3+ ions over other relevant competitive metal ions. Interestingly, the binding of sensor 3a and the V-NPs with Cu2+ and Fe3+ ions manifested an instant color change from yellow to Eight green and colorless, respectively, in daylight, which is detectable by the naked-eye, and a fluorescence turn-off response under UV Eight. The results demonstrate that the organic-inorganic nanohybrids exhibited better sensitivity, greater affinity and Lower Limit of detection Leading to better response time than the parent 3a towards Cu2+ and Fe3+ ions in the optimum physiological pH range. A computational analysis using the DFT approach was performed to gain insight into the complexation mode of 3a with Cu2+ and Fe3+ ions. In addition to this, anti-oxidant properties were also investigated for compounds 3a-3c. Altogether, these findings pave the way for the design and synthesis of dual metal ion sensors.