Fluorescence response of TICT-active aminostilbenes to copper(II) ions: redox reaction vs ion recognition
作者:Cheng-Kai Lin、Jye-Shane Yang
DOI:10.1007/s11164-012-0627-5
日期:2013.1
Cu(II)-selective fluorescence enhancement (1, 2, and 4) or fluorescence quenching (3) was observed for aminostilbenes 1–4 in acetonitrile. The fluorescence responses result from efficient Cu(II)-mediated oxidation of 1–4 that forms new fluorescent species rather than from any specific noncovalent interactions. Evidence of redox reactions includes irreversible Cu(II) titration spectra, spectroscopic observation of the radical cations, and isolation of oxidized aminostilbene dimers. These results provide a new method for synthesis of tetrasubstituted tetrahydrofurans and suggest that aminostilbenes with twisted intramolecular charge-transfer activity are potential fluorescence-enhanced Cu(II) chemodosimeters. The role of Cu(II)-mediated redox reactions should be always taken into account in mechanisms for sensing of arylamine-based Cu(II)-selective fluoroionophores.
在乙腈中观察到氨基二苯乙烯 1-4 的 Cu(II)选择性荧光增强(1、2 和 4)或荧光淬灭(3)。这些荧光反应是由于 Cu(II)介导的 1-4 高效氧化作用形成了新的荧光物种,而不是由于任何特定的非共价相互作用。氧化还原反应的证据包括不可逆的 Cu(II)滴定光谱、自由基阳离子的光谱观察以及氧化氨基二苯乙烯二聚体的分离。这些结果为合成四代四氢呋喃提供了一种新方法,并表明具有分子内电荷转移扭曲活性的氨基二苯乙烯是潜在的荧光增强型 Cu(II) 化学模拟物。在芳胺基 Cu(II)选择性荧光团的传感机制中,应始终考虑 Cu(II)介导的氧化还原反应的作用。