detection of fluoride anion. The addition of F− to a solution of probe 1 in tetrahydrofuran resulted in evident naked-eye color change from green-yellow to orange-red under daylight and obvious fluorescence quenching within 3 s. And the detection limit toward F− was calculated to be as low as 2.16 × 10−7 mol/L. 1H NMR titrations proved that the interaction between 1 and fluoride ion: hydrogenbond at low
据报道,以香豆素为基的新型香豆素基化合物1为比色和荧光探针,用于检测氟阴离子。F的加成-到探针的溶液1在四氢呋喃中导致从绿黄色至橙红色在日光和明显的荧光淬灭在3秒内明显肉眼颜色变化。检出限朝向˚F -计算为低至2.16×10 -7 摩尔/升。1 H NMR滴定证明1之间的相互作用氟离子:低氟离子浓度的氢键,高氟离子浓度的去质子。此外,它表现出高灵敏度和选择性与F -比其他检测离子(氯- ,溴- ,我-,ACO -,NO 3 -,HSO 4 -,H 2 PO 4 - )的四氢呋喃溶液中。
Extensive Reduction in Back Electron Transfer in Twisted Intramolecular Charge-Transfer (TICT) Coumarin-Dye-Sensitized TiO<sub>2</sub>Nanoparticles/Film: A Femtosecond Transient Absorption Study
作者:Tushar Debnath、Partha Maity、Hyacintha Lobo、Balvant Singh、Ganapati S. Shankarling、Hirendra N. Ghosh
DOI:10.1002/chem.201303903
日期:2014.3.17
polarity of the solvent and the solution pH, suggest that both photoexcited dyes exist in a locally excited (LE) state in solvents of low polarity. In highly polarsolvents, however, C1 exists in an intramolecular charge‐transfer (ICT) state, whereas C2 exists in both ICT and twisted intramolecular charge‐transfer (TICT) states, their populations depending on the degree of polarity of the solvent and the pH
我们报告了两种结构相似的香豆素染料(C1和C2)的合成,表征以及光学和电化学性质。这些染料已被用作TiO 2纳米粒子和薄膜中的敏化剂,并且研究了分子结构对界面电子转移动力学的影响。在C1和C2上进行稳态光学吸收,发射和时间分辨发射的研究,改变了溶剂的极性和溶液的pH值,表明这两种光激发染料均在低极性溶剂中以局部激发(LE)状态存在。但是,在高极性溶剂中,C1以分子内电荷转移(ICT)状态存在,而C1以分子内电荷转移(ICT)状态存在。C2以ICT和扭曲的分子内电荷转移(TICT)状态存在,其数量取决于溶剂的极性程度和溶液的pH值。我们采用飞秒瞬态吸收光谱法来监测C1和C2敏化的TiO 2纳米颗粒和薄膜中的电荷转移动力学。通过直接检测TiO 2纳米粒子的导带中的电子以及瞬态吸收光谱的可见光和近红外区域中染料的自由基阳离子,已经证实了电子注入。在C1 / TiO 2和C2 / TiO 2中均进
A colorimetric and fluorogenic probe for bisulfite using benzopyrylium as the recognition unit
A coumarin–benzopyrylium (CB) platform has been developed for the colorimetric and fluorogenic detection of bisulfite. The proposed probe utilizes coumarin as the fluorophore and positively charged benzopyrylium as the reaction site. The method employs the nucleophilic addition of bisulfite to the benzopyrylium moiety of CB to inactivate the electron-deficient oxonium ion. The driving force for photo-induced electron transfer is considerably diminished, thereby promoting the emission intensity of the coumarin fluorophore. The fluorescence intensity at 510 nm is linear with bisulfite concentration over a range of 0.2–7.5 μM with a detection limit of 42 nM (3δ). CB shows a rapid response (within 30 s) and high selectivity and sensitivity for bisulfite. Preliminary studies show that CB has great potential for bisulfite detection in real samples and in living cells.