MCM-41 supported imidazole-based dithienylethene: Efficient and recyclable fluorescent chemosensor for Fe³⁺ ions in aqueous media

An imidazole-based dithienylethene (DTE) was successfully synthesised and immobilized into MCM-41 mesoporous silica surface to prepare efficient and recyclable Fe³⁺ ions fluorescent chemosensors. In this work, DTE was immobilized into commercial MCM-41 and amino-functionalized MCM-41 (N-MCM-41) via physical method to afford DTE@MCM-41 and DTE@N-MCM-41 materials, respectively. DTE was also incorporated into MCM-41 through chemical bonding after reaction between iodopropyl-functionalized MCM-41 (I-MCM-41) and DTE to form DTE-MCM-41 material. The obtained materials were fully characterized and evaluated as Fe³⁺ ions selective fluorescent chemosensors in aqueous media over various metal ions. The fluorescence intensity of MCM-41 supported DTE was quenched immediately after the addition of Fe³⁺ ions. In addition, the detection limit (DL) of MCM-41 supported DTE (DTE-MCM-41) was found to be 1.42 nM. Furthermore, the reusability of these three materials was also investigated during four successive cycles. Materials DTE-MCM-41 and DTE@N-MCM-41 exhibited higher stability than DTE@MCM-41.