基于分子内电荷转移机制的巯基荧光比色化学传感器

A Thiol-selective Colorimetric and Fluorescent Sensor Based on Intramolecular Electron Transfer

设计并合成了以香豆素为荧光发色团的多氰基分子化合物TCC。分子内强烈的电荷转移效应使得其本身荧光较弱。巯基化合物如半胱氨酸(Cys)、高半胱氨酸(Hcy)和还原型谷胱甘肽(GSH)的加入能与TCC中的三氰基乙烯基进行加成反应从而破坏分子内电荷转移,使分子内电荷转移吸收峰消失,颜色由紫色变成黄绿色,最大吸收波长由560 nm移至380 nm。并且化合物的荧光也随着巯基化合物的加入逐渐增强,荧光的强度与巯基化合物的浓度有很好的线性关系,检测限可以达到10^(-5)mol/L。其它离子与不含巯基的氨基酸则不会与化合物TCC发生上述反应,也就不会对体系的吸收和荧光光谱产生明显的影响,从而实现高效、专一的识别巯基化合物。

A coumarin-derived multicyano compound（TCC） with strong ICT character was designed and synthesized.The weak fluorescence of TCC was observed due to the formation of strong intramolecular charge transfer state.Upon introduction of thiols such as cysteine,homocysteine and glutathione,the absorption band at 560 nm in TCC gradually decreased with visual color change from violet to yellow-green,whereas the fluorescence intensity increased.There is a liner relationship between the intensity of TCC at 560 nm and the concentration of thiol with the limit of detection as low as 10～- ol/L.Other common sulphydryl-free amino acids cannot react with TCC and do not cause any absorption and emission spectral changes,indicating that TCC shows high selectivity and sensitivity to sulfhydryl compounds.