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Fluorescence quenching and electronic interaction of (S)-5-(dimethylamino)-N-(1-phenylethyl)naphthalene-1-sulfonamide for selective nitroaromatic detection and DFT study.

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Title:	Fluorescence quenching and electronic interaction of (S)-5-(dimethylamino)-N-(1-phenylethyl)naphthalene-1-sulfonamide for selective nitroaromatic detection and DFT study.
Authors:	Muhammad, Imran¹ (AUTHOR) imrantotkay@gmail.com, Han, Rong² (AUTHOR), Ren, Tie Zhen¹ (AUTHOR) rtz@xju.edu.cn, Zha, Chun-Mei¹ (AUTHOR), Shahzad, Adnan³ (AUTHOR), Ullah, Ihsan³ (AUTHOR)
Source:	Structural Chemistry. Jun2026, Vol. 37 Issue 3, p1265-1279. 15p.
Subjects:	Fluorescence quenching, Nitroaromatic compounds, Photoinduced electron transfer, Density functional theory, Fluorophores, Hydrogen bonding, Solvatochromism
Abstract:	The development of selective and sensitive sensing systems for nitroaromatics (NACs) is critical for environmental monitoring. In this study, we investigate the structural and electronic properties of (S)-5-(Dimethylamino)-N-(1-phenylethyl)naphthalene-1-sulfonamide (D) using density functional theory (DFT) and fluorescence spectroscopy. D exhibits strong non-covalent interactions primarily hydrogen bonding with NACs, including metronidazole (MNZ), 4-nitrophenol (4NP), 2-nitrophenol (2NP), picric acid (PA), chloro-nitrobenzene (ClNB), and nitrobenzene (NB). Frontier molecular orbital, TDOS/PDOS, and electrostatic potential analyses reveal that electron-rich sulfonyl oxygens (O-p) in D preferentially engage in hydrogen bonding with analyte protons (H–s). This interaction significantly reduces the HOMO–LUMO gap (4.15 to 3.25 eV for D–MNZ) and increases electrophilicity (up to 5.06 eV for D–MNZ), supporting enhanced electron-accepting ability. Complexation energies further confirm strong binding, especially with MNZ (− 2.57 eV). Experimentally, D exhibits pronounced solvatochromism, with emission maxima shifting from 477 nm in n-hexane to 553 nm in water, and fluorescence intensity peaking at 369 a.u. in DMF; notably, low fluorescence intensity in water and irregular responses in n-hexane and cyclohexane. To understand these observations at the molecular level, TDDFT calculations were performed using the COSMO solvation model. Simulations confirm solvent influence and reveal that complexation with NACs in acetonitrile induces a red shift in emission (~ 480 nm) alongside substantial fluorescence quenching. This effect is most pronounced for MNZ (3.99 × 10−⁶), 4NP (2.19 × 10−5), 2NP (1.36 × 10−4), and PA (1.37 × 10−4), consistent with strong hydrogen bonding and photoinduced electron transfer. Together, these experimental and theoretical findings underscore the high selectivity and environmental responsiveness of D as a fluorophore for the detection of electron-deficient NACs analytes. [ABSTRACT FROM AUTHOR]
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Database:	Engineering Source

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Abstract:	The development of selective and sensitive sensing systems for nitroaromatics (NACs) is critical for environmental monitoring. In this study, we investigate the structural and electronic properties of (S)-5-(Dimethylamino)-N-(1-phenylethyl)naphthalene-1-sulfonamide (D) using density functional theory (DFT) and fluorescence spectroscopy. D exhibits strong non-covalent interactions primarily hydrogen bonding with NACs, including metronidazole (MNZ), 4-nitrophenol (4NP), 2-nitrophenol (2NP), picric acid (PA), chloro-nitrobenzene (ClNB), and nitrobenzene (NB). Frontier molecular orbital, TDOS/PDOS, and electrostatic potential analyses reveal that electron-rich sulfonyl oxygens (O-p) in D preferentially engage in hydrogen bonding with analyte protons (H–s). This interaction significantly reduces the HOMO–LUMO gap (4.15 to 3.25 eV for D–MNZ) and increases electrophilicity (up to 5.06 eV for D–MNZ), supporting enhanced electron-accepting ability. Complexation energies further confirm strong binding, especially with MNZ (− 2.57 eV). Experimentally, D exhibits pronounced solvatochromism, with emission maxima shifting from 477 nm in n-hexane to 553 nm in water, and fluorescence intensity peaking at 369 a.u. in DMF; notably, low fluorescence intensity in water and irregular responses in n-hexane and cyclohexane. To understand these observations at the molecular level, TDDFT calculations were performed using the COSMO solvation model. Simulations confirm solvent influence and reveal that complexation with NACs in acetonitrile induces a red shift in emission (~ 480 nm) alongside substantial fluorescence quenching. This effect is most pronounced for MNZ (3.99 × 10−⁶), 4NP (2.19 × 10−5), 2NP (1.36 × 10−4), and PA (1.37 × 10−4), consistent with strong hydrogen bonding and photoinduced electron transfer. Together, these experimental and theoretical findings underscore the high selectivity and environmental responsiveness of D as a fluorophore for the detection of electron-deficient NACs analytes. [ABSTRACT FROM AUTHOR]
ISSN:	10400400
DOI:	10.1007/s11224-025-02620-5