方酰胺负载型催化剂的应用及汞离子荧光探针的合成

发布时间：2018-06-13 14:08

本文选题：介孔硅材料 + 自组装　；参考：《上海师范大学》2017年硕士论文

【摘要】：介孔硅材料具有有序的孔道、可调的孔径、可控的形貌结构,这些特点使其成为有效的催化剂载体;特别是构建具有亲水性的这类介孔硅材料作为催化剂,在催化反应中具有重要的意义,这些具有亲水性的硅材料作为催化剂不仅能提高在水介质反应体系的分散度、提高反应速度,而且能够重复使用。本论文第一部分通过点击化学的策略,将手性有机小分子方酰胺类催化剂负载在亲水性的介孔硅材料,制备了手性方酰胺负载型催化剂,并成功地应用于水介质的不对称迈克尔加成反应。汞离子(Hg~(2+))是有毒的重金属元素之一。所以对汞离子的选择性识别具有重要意义。在众多的检测重金属离子的方法中,荧光探针因具有快速准确、灵敏度高、专一性强的特点受到众多研究者的关注。而扩大荧光探针的适用范围,简化探针的探测条件就是目前主要的优化方向。(1)在本文第一部分中,利用聚乙二醇单甲基醚和超支化聚乙氧基硅烷发生酯交换反应,制备了亲水性的聚合物前驱体;该聚合物前驱体与功能硅源3-巯丙基三乙氧基硅烷共聚合,组装形成巯基功能化的介孔硅球;最后利用点击反应将有机小分子催化剂方酰胺嫁接到材料上,制备了具有囊泡球型结构的手性方酰胺负载型催化剂。该催化剂对乙酰丙酮与硝基烯烃的不对称迈克加成反应表现出良好的催化活性(转化率高达99%)和对映选择性(手性值高达99%),同时该催化剂通过简单的离心回收并再利用8次,仍保持其较高的催化活性。(2)在本文第二部分中,设计、合成了一种基于氟硼吡咯为荧光团和肼为活性基团的汞离子荧光探针;该探针在水溶液中能在5分钟内完成对汞离子的检测。研究发现,该探针在水溶液中随着汞离子浓度的增加,溶液紫外吸收明显红移,荧光强度大大增强;即使是浓度非常低的汞离子(0.1μM)存在也可以使体系的荧光强度明显增强,说明了其具有非常好的灵敏度。另外通过选择性实验表明该探针在同样条件下对其它常见金属离子没有明显响应,说明该探针具有很好的选择性。
[Abstract]:Mesoporous silicon materials have ordered pore channels, adjustable pore size, controllable morphology and structure, which make them effective catalyst carriers, especially for the construction of hydrophilic mesoporous silicon materials as catalysts. These hydrophilic silicon materials as catalysts can not only increase the dispersion of the reaction system in water medium, but also can be reused. In the first part of this thesis, the chiral small molecular siloxane catalysts were prepared by clicking on the strategy of chemistry and supported on hydrophilic mesoporous silicon materials. It has been successfully applied to the asymmetric Michael addition reaction in water medium. Mercury ion (HG) is one of the toxic heavy metals. Therefore, the selective recognition of mercury ions is of great significance. Among the many methods for the detection of heavy metal ions, fluorescent probes have attracted much attention because of their rapid, accurate, high sensitivity and strong specificity. In the first part of this paper, the transesterification reaction between polyethylene glycol monomethyl ether and hyperbranched poly (ethoxy) silane is carried out. A hydrophilic polymer precursor was prepared, which was copolymerized with functional silicon source 3-mercapto triethoxy silane to form mercapto functionalized mesoporous silica spheres. Finally, the small organic catalyst was grafted onto the material by click-down reaction, and a chiral catalyst with vesicular spheroid structure was prepared. The catalyst showed good catalytic activity (conversion up to 99%) and enantioselectivity (chiral value as high as 99g) for asymmetric Michael addition reaction of acetylacetone with nitroolefins, and the catalyst was recovered by simple centrifugation and reused for 8 times. In the second part of this paper, we designed and synthesized a mercury fluorescence probe based on fluorboron pyrrole as fluorescence group and hydrazine as active group. The probe can detect mercury ions in aqueous solution within 5 minutes. It was found that with the increase of mercury ion concentration in aqueous solution, the UV absorption of the probe shifted significantly and the fluorescence intensity was greatly enhanced, and the fluorescence intensity of the system could be significantly enhanced by the presence of the very low concentration mercury ion (0.1 渭 M). It shows that it has very good sensitivity. In addition, the selective experiments show that the probe has no obvious response to other common metal ions under the same conditions, which indicates that the probe has a good selectivity.
【学位授予单位】：上海师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;O657.3

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