衍生于苯并-12-冠-4的双光子荧光Fe^(3+)探针

A Two-photon Fluorescence Sensor for Fe^(3+) Derived from Benzo-12-crown-4

合成了双光子荧光探针2,5-二氰基-1,4-二[2′-(4′-苯并-12-冠-4)乙烯基]苯(1),并进行了红外、质谱及元素分析。探针1在单、双光子荧光发射中对金属离子显示了相似的选择性,双光子过程中的选择性略优于单光子过程,并对Fe3+显示出高度选择性识别。探针1对Fe3+的单、双光子荧光强度随Fe3+浓度的升高而急剧降低;单、双光子荧光滴定过程中探针对Fe3+的络合常数分别是:5.70±0.03(logK11)与4.74±0.05(logK12)、5.76±0.04(logK11)与4.81±0.07(logK12)。探针1的双光子吸收截面(δTPA)随溶剂极性增加而减小,在甲苯与乙腈中的δTPA分别是2198,1125GM,探针与Fe3+络合后其双光子吸收截面显著减小。研究结果表明,化合物1可以作为Fe3+探针应用到单光子激发荧光与双光子激发荧光检测;可以用开发单光子荧光探针的策略来设计应用于生物成像的双光子荧光探针。

2,5-Dicyano-1,4-bis2′-（4′-benzo-12-crown-4） vinylbenzene as two-photon fluorescence sensor 1 was synthesized,and its structure was characterized by IR,MS and elemental analyses.Similar selectivity of sensor 1 toward metal ions was found in one-photon excited fluorescence（OPEF） and two-photon excited fluo-rescence（TPEF） experiments,and sensor 1 shows a better selectivity for metal ions in TPEF than that in OPEF and a highly selective recognition for ferric ion.The OPEF and TPEF intensities of sensor 1 conspicuously decreased with the increase of ferric ion concentration,and the binding constants of 1 for ferric ion,expressed as logK,were determined from the OPEF-and TPEF-titration curves to be 5.70±0.03（logK 11 ） and 4.74±0.05（logK 12 ） ,and 5.76±0.04（logK 11 ） and 4.81±0.07（logK 12 ） at 20℃in MeCN,respectively.Two-photon absorption cross section（δ TPA ） of sensor 1 prominently abated with the increase of solvent polarity,andδ TPA values in toluene and in CH3 CN are 2198 and 1125 GM at 780 nm,respectively.