双氰基二苯代乙烯型双光子荧光汞离子探针

Dicyanostilbene-derived Two-photon Fluorescence Probe for Mercury Ions

分别以双氰基二苯代乙烯(DCS)和双[2-(2-羟乙基硫基)乙基]氨(HSA)为双光子荧光团和汞离子受体,合成了双光子荧光汞离子探针(DHg),并对其结构进行了分析.实验结果表明,DHg在甲苯、乙腈和水中的荧光量子产率(Φ)分别为0.78,0.42和0.20,对汞离子的络合常数通过单、双光子荧光滴定分别拟合为lg K=5.47±0.02和lg K=5.34±0.02.DHg在水溶液中对汞离子具有优良的选择性和高的灵敏性,可用于中性环境中汞离子的检测.DHg的双光子吸收截面(δTPA)在水溶液中高达840 GM,可用于细胞中汞离子的检测与成像.

A novel water-soluble two-photon fluorescent probe for Hg2＋（ DHg） derived from dicyanostilbene（ DCS） as a two-photon fluorophore and bis[2-（ 2-hydroxyethyl sulfanyl） ethyl]amino group（ HAS） as a novel Hg2＋ligand was developed,and its structure was analyzed and identified. The results of UV-Vis absorption and absorption-titration experiments,one-and two-photon excited fluorescence experiments,as well as cellimaging and tissue-imaging experiments showed that the probe has a very high sensitivity and selectivity for the detection of Hg2＋in water. It can be used to detect trace Hg2＋in neutral or basic aqueous solution（ p H = 7—12）,and its binding constant（ lg K） for Hg2＋was determined from the one-and two-photon fluorescence-titration curves to be lg K = 5. 47±0. 02 and lg K = 5. 34±0. 02,respectively. Nitrogen atom property and the sulfur atom number on the ionophore are believed to be responsible of the unique selectivity of probe DHg for Hg2＋. The fluorescent quantum yields of DHg in toluene,acetonitrile and water are 0. 78,0. 42 and 0. 20,respectively,and its two-photon absorption cross-section（ δTPA） is as high as 840 GM in aqueous solution. The probe could selectively detect free Hg2＋ions in live cells without interference from other metal ions and the membranebound probes. Undoubtedly,the probe is an ideal two-photon excited fluorescence bioimaging candidate.