Design, Preparation, Characterization, Density Functional Theory, and HOMO‐LUMO Perspective of Fe3O4@SiO2‐Pr‐NH‐IC as a New Nanomagnetic Chemosensor

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ABSTRACTIn this research, the Fe3O4@SiO2‐Pr‐NH‐IC magnetic nanoparticles (MNPs) were synthesized based on Fe3O4 nanoparticles. Initially, Fe3O4 was coated with tetraethylorthosilicate (TEOS) to produce Fe3O4@SiO2, which was functionalized by the reaction with 3‐aminopropyl three‐methoxy silane (APTMS) to yield Fe3O4@SiO2‐Pr‐NH2, followed by the treatment with indole‐3‐carbaldehyde (IC) to obtain Fe3O4@SiO2‐Pr‐NH‐IC as target hybrid organic and inorganic material. The Fe3O4@SiO2‐Pr‐NH‐IC was analyzed using photoluminescence spectroscopy. It was shown that this compound can selectively detect Al3+ ions in aqueous media among various cations, with a limit of detection (LOD) of 2.47 × 10−6 M. Comprehensive DFT calculations were carried out utilizing the B3LYP functional in conjunction with the 6‐311g (d,p) and LANL2DZ basis sets to analyze the ground state of the system. To elucidate the interaction mechanism, the MEP map was generated, and a full geometry optimization was performed. Additionally, the electronic properties and chemical reactivity were examined through a HOMO‐LUMO analysis at the same computational level. The findings revealed that the incorporation of the Al3+ ion significantly enhances the reactivity of the Pr‐NH‐IC + Al3+ complex in comparison to the free Pr‐NH‐IC structure. These findings suggest that Fe3O4@SiO2‐Pr‐NH‐IC has significant potential for the development of advanced sensor systems for the selective detection of Al3+ ions in aqueous environments. Future research could focus on the modification of the nanostructure to enhance its sensitivity and selectivity toward other environmentally and biologically relevant metal ions. Additionally, the integration of this material into portable sensing devices or the development of a real‐time detection system could pave the way for practical applications in environmental monitoring and water quality assessment.