Structure–Driven Intramolecular Charge Transfer Modulation in Imidazole Fluorophores for Selective Hydrazine Detection and Forensic Applications
- 1Chung Yuan Christian University , , , ,
- 2National Yang Ming Chiao Tung University , , , ,
Abstract
Hydrazine is a highly toxic, potentially carcinogenic compound widely used in industry, necessitating sensitive detection. Meanwhile, latent fingerprint identification requires high-contrast, high-resolution imaging. Both demand rapid and visually discernible signals, motivating the development of integrated materials for simultaneous chemical sensing and forensic imaging. Herein, we report a rationally designed imidazole-based fluorophore, DPI–DCN, that integrates reaction-based hydrazine sensing with high-resolution latent fingerprint (LFP) visualization. By incorporating a strongly electron-withdrawing dicyanovinyl unit, DPI–DCN establishes an efficient donor–acceptor framework, leading to enhanced intramolecular charge transfer (ICT) and pronounced bathochromic shifts relative to its ester analogue, DPI–DET. These photophysical characteristics are supported by density functional theory calculations, which reveal a reduced HOMO–LUMO gap and favorable orbital separation. DPI–DCN exhibits excellent selectivity toward hydrazine, displaying a distinct fluorescence “turn-off” response with a low detection limit of 1.94 μM. Mechanistic investigations using 1H NMR and mass spectrometry confirm that nucleophilic addition of hydrazine to the dicyanovinyl moiety disrupts π-conjugation and suppresses ICT, accounting for the observed optical changes. Beyond solution-phase sensing, DPI–DCN functions as an effective solid-state fluorescent powder for LFP development, enabling high-contrast imaging across diverse substrates, including aged fingerprints. Notably, multilevel fingerprint features up to level III are clearly resolved, demonstrating its capability for detailed forensic analysis. This work establishes a direct structure–property–function relationship and presents a versatile molecular platform that bridges chemical sensing and forensic imaging, offering new opportunities for integrated analytical and security applications.
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BibTeX
@article{chen2026structuredriven,
title = {{Structure–Driven Intramolecular Charge Transfer Modulation in Imidazole Fluorophores for Selective Hydrazine Detection and Forensic Applications}},
author = {Yu-Hsin Chen and Yu-Hong Chen and Wei-Ting Chien and Hsin-Chieh Lin and Mei-Yu Yeh},
journal = {ACS omega},
year = {2026},
month = oct,
doi = {10.1021/acsomega.6c06606},
url = {https://europepmc.org/article/PMC/PMC13670760},
note = {CC BY},
}
RIS
TY - JOUR
TI - Structure–Driven Intramolecular Charge Transfer Modulation in Imidazole Fluorophores for Selective Hydrazine Detection and Forensic Applications
AU - Yu-Hsin Chen
AU - Yu-Hong Chen
AU - Wei-Ting Chien
AU - Hsin-Chieh Lin
AU - Mei-Yu Yeh
PY - 2026
DA - 2026/10/01
JO - ACS omega
DO - 10.1021/acsomega.6c06606
UR - https://europepmc.org/article/PMC/PMC13670760
AB - Hydrazine is a highly toxic, potentially carcinogenic compound widely used in industry, necessitating sensitive detection. Meanwhile, latent fingerprint identification requires high-contrast, high-resolution imaging. Both demand rapid and visually discernible signals, motivating the development of integrated materials for simultaneous chemical sensing and forensic imaging. Herein, we report a rationally designed imidazole-based fluorophore, DPI–DCN, that integrates reaction-based hydrazine sensing with high-resolution latent fingerprint (LFP) visualization. By incorporating a strongly electron-withdrawing dicyanovinyl unit, DPI–DCN establishes an efficient donor–acceptor framework, leading to enhanced intramolecular charge transfer (ICT) and pronounced bathochromic shifts relative to its ester analogue, DPI–DET. These photophysical characteristics are supported by density functional theory calculations, which reveal a reduced HOMO–LUMO gap and favorable orbital separation. DPI–DCN exhibits excellent selectivity toward hydrazine, displaying a distinct fluorescence “turn-off” response with a low detection limit of 1.94 μM. Mechanistic investigations using 1H NMR and mass spectrometry confirm that nucleophilic addition of hydrazine to the dicyanovinyl moiety disrupts π-conjugation and suppresses ICT, accounting for the observed optical changes. Beyond solution-phase sensing, DPI–DCN functions as an effective solid-state fluorescent powder for LFP development, enabling high-contrast imaging across diverse substrates, including aged fingerprints. Notably, multilevel fingerprint features up to level III are clearly resolved, demonstrating its capability for detailed forensic analysis. This work establishes a direct structure–property–function relationship and presents a versatile molecular platform that bridges chemical sensing and forensic imaging, offering new opportunities for integrated analytical and security applications.
SN - 2470-1343
ER -