4-氨基-7-硝基苯并-2-氧杂-1,3-二唑类衍生物的合成及其对Hg(Ⅱ)的识别研究

摘要

以4-氯-7-硝基苯并-2-氧杂-1,3-二唑、乙二胺和溴乙酸乙酯等为原料,合成4-氨基-7-硝基苯并-2-氧杂-1,3-二唑类衍生物(NBD-OEt),通过IR、NMR和MS对其进行结构表征.研究了NBD-OEt的吸收光谱和荧光光谱性质,探讨其在pH 7.40、含40％无水乙醇的HEPES水溶液缓冲体系中对Hg2+的响应以及NBD-OEt与Hg2的结合模式.结果表明,随Hg2的不断加入,NBD-OEt在476nm的吸收峰红移至514nm,并有两个等吸收点(347和482nm);其荧光发射峰由536nm红移至559nm,且在525nm出现等发射点.通过等摩尔连续变化法测得NBD-OEt与Hg2以1∶1的计量比结合.%A novel 4-amino-7-nitrobenzo-2-oxa-1,3-oxadiazole derivative (NBD-OEt) were synthesized via two steps by using 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl),ethylenediamine and ethyl bromoacetate as raw materials.The structure of NBD-OEt was confirmed by 1H NMR,13C NMR and ESI-MS.The response to Hg2+ in HEPES aqueous buffer system containing 40 ％ ethanol at pH 7.40,and the binding mode of NBD-OEt with Hg2 + were investigated.The results showed that the addition of Hg2 + could induce the red-shift of absorption band from 476 nm to 514 nm.Two clear isoabestic point were observed at 347 nm and 482 nm.With increasing the concentration of Hg2+,the weak fluorescence emission peak at 536 nm of NBD-OEt was intensified and red shifted to 559 nm with a obvious isoemission at 525 nm.Job's test showed that receptor NBD-OEt coordinate to Hg2+ in a 1∶1 stoichiometry.