A novel heterogeneous ionic liquid-functionalized nanoporous material of SBA-15-based fluorescent chemosensor for ultra-selective Hg2+ detection coupled with DFT mechanistic insights
Journal of Molecular Liquids, cilt.438, 2025 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 438
- Basım Tarihi: 2025
- Doi Numarası: 10.1016/j.molliq.2025.128701
- Dergi Adı: Journal of Molecular Liquids
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC
- Anahtar Kelimeler: 2,4,6-triaminopyrimidine, Chemosensor, DFT, heterogeneous ionic liquid-functionalized, Hg2+ ions, SBA-Pr-CQC-TAP
- Süleyman Demirel Üniversitesi Adresli: Evet
Özet
SBA-15 mesoporous silica, owing to its high surface area and tunable porosity, provides an excellent platform for chemosensor design. In this work, we report the synthesis of a novel heterogeneous ionic liquid-functionalized nanomaterial, SBA-Pr-CQC-TAP, through surface modification of SBA-15 with 2-chloroquinoline-3-carbaldehyde and 2,4,6-triaminopyrimidine. Comprehensive characterization (FT-IR, FE-SEM, EDX, BET, TGA, and XRD) confirmed the successful functionalization while preserving the ordered mesostructure. Fluorescence studies demonstrated that SBA-Pr-CQC-TAP acts as an ultra-selective chemosensor for Hg2+ ions, exhibiting significant fluorescence quenching with a detection limit of 5.4 × 10−8 M, superior to many previously reported SBA-15-based sensors. Competition experiments revealed excellent selectivity for Hg2+ even in the presence of other competing metal ions. Mechanistic analysis showed that fluorescence quenching occurs via static quenching, arising from ground-state complex formation between Hg2+ and the NH2/nitrogen-rich sites of the chemosensor. DFT calculations supported the experimental results, revealing that Hg2+ preferentially binds to the N4, N5, and N6 atoms, lowering the system energy by 42.70 Hartree and reducing the HOMO-LUMO gap from 4.23 eV (free sensor) to 1.76 eV (Hg2+-bound sensor). This reduced energy gap enhances intramolecular charge transfer and explains the observed quenching mechanism. Collectively, these findings establish SBA-Pr-CQC-TAP as a robust, highly sensitive, and selective platform for Hg2+ ion detection, with both experimental and theoretical evidence supporting its sensing mechanism.