Goswami Nidhi, Naithani Sudhanshu, Mangalam Jimmy, Yadav Vikas, Saini Saakshi, Roy Partha, Goswami Tapas, Kumar Sushil
Department of Chemistry, School of Engineering, UPES Dehradun 248007, Uttarakhand, India.
Nanoscopic Imaging and Sensing Lab, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2025 Oct 5;338:126123. doi: 10.1016/j.saa.2025.126123. Epub 2025 Apr 3.
The severe toxicity and widespread distribution of fluoride (F) and cyanide (CN) ions in various environmental matrices highlight the urgent need for their efficient and reliable detection methods. In this study, we present a fluorogenic imidazo-phenanthroline based probe (L) for selective detection of F and CN in semi-aqueous medium. Probe L exhibits a pronounced ratiometric fluorescence response upon interaction with these anions, driven by hydrogen bonding interaction involving the N-H group of the imidazole moiety. Notably, L enables clear discrimination of CN from other anions through a distinct color change, with an impressive detection limit in the nanomolar (nM) range. To enhance its practical applicability, paper-based sensing strips embedded with L were developed, effectively detecting CN and F under UV light illumination. The probe's exceptional sensitivity and selectivity could be attributed to the strong acidity of the N-H proton, facilitating efficient hydrogen bonding interactions followed by deprotonation. The binding mechanism was thoroughly investigated using Job's plot, NMR, and DFT analyses. Additionally, L demonstrated versatility in environmental and biological applications, successfully detecting cyanide and fluoride ions in soil samples and identifying F in live MCF-7 cell lines via blue fluorescence channel imaging.
氟（F）离子和氰化物（CN）离子在各种环境基质中的高毒性和广泛分布凸显了对其高效可靠检测方法的迫切需求。在本研究中，我们提出了一种基于荧光咪唑 - 菲咯啉的探针（L），用于在半水介质中选择性检测F和CN。探针L在与这些阴离子相互作用时表现出明显的比率荧光响应，这是由涉及咪唑部分N - H基团的氢键相互作用驱动的。值得注意的是，L通过明显的颜色变化能够清晰地区分CN与其他阴离子，在纳摩尔（nM）范围内具有令人印象深刻的检测限。为了提高其实际适用性，开发了嵌入L的纸质传感条，在紫外光照射下能有效检测CN和F。该探针的卓越灵敏度和选择性可归因于N - H质子的强酸性，有利于高效的氢键相互作用随后去质子化。使用Job曲线、核磁共振（NMR）和密度泛函理论（DFT）分析对结合机制进行了深入研究。此外，L在环境和生物应用中表现出多功能性，成功检测了土壤样品中的氰化物和氟离子，并通过蓝色荧光通道成像在活的MCF - 7细胞系中识别了F。
