Jayaprakash Ajay, Mol K M Rakhi, Porel Mintu
Department of Chemistry, Indian Institute of Technology Palakkad Kerala 678557 India
Environmental Sciences and Sustainable Engineering Centre, Indian Institute of Technology Palakkad Kerala 678557 India.
RSC Adv. 2025 May 13;15(20):15801-15805. doi: 10.1039/d5ra01092f. eCollection 2025 May 12.
The design and synthetic strategy of hybrid mono and bidentate dansyl-triazine ligands (DTM and DTD) for selective sensing of fluoride anion are reported. The synthesised compounds were characterised using spectroscopic techniques such as H NMR, LC-MS, IR, UV-vis absorption and emission and corroborated with theoretical methods. Studies showed that the bidendate ligand (DTD) exhibits intra-molecular charge transfer (ICT) from the donor dansyl fluorophore (HOMO) to the triazine acceptor (LUMO). On the other hand, electron density of the HOMO and LUMO of the mono ligand is localised on the dansyl group. Interestingly, these ligands showed selective detection of fluoride anions with a limit of detection (LOD) of 1.31 μM and 294 nM for the DTM and DTD ligands respectively. The electrostatic potential surface mapping suggests that the hydrogen bonding between NH of the ligand and fluoride ion as the underlying mechanism for sensing. Time-correlated single photon counting (TCSPC) analyses further validate this rationale, where DTM showed a lifetime of 3.56 ns and DTD 1.65 ns. Upon binding, the lifetime increases, this may be attributed to the restricted molecular rotation upon hydrogen bonding.
报道了用于选择性传感氟离子的混合单齿和双齿丹磺酰 - 三嗪配体（DTM和DTD）的设计与合成策略。使用诸如¹H NMR、LC - MS、IR、紫外 - 可见吸收和发射等光谱技术对合成的化合物进行了表征，并通过理论方法进行了佐证。研究表明，双齿配体（DTD）表现出从供体丹磺酰荧光团（HOMO）到三嗪受体（LUMO）的分子内电荷转移（ICT）。另一方面，单齿配体的HOMO和LUMO的电子密度定域在丹磺酰基团上。有趣的是，这些配体对氟离子表现出选择性检测，DTM和DTD配体的检测限（LOD）分别为1.31 μM和294 nM。静电势表面映射表明，配体的NH与氟离子之间的氢键是传感的潜在机制。时间相关单光子计数（TCSPC）分析进一步验证了这一原理，其中DTM的寿命为3.56 ns，DTD的寿命为1.65 ns。结合后，寿命增加，这可能归因于氢键作用下分子旋转受限。
