【作者】 张乐杰；

【导师】 段春迎；

【作者基本信息】 大连理工大学 ， 无机化学， 2012， 硕士

【摘要】 发光金属有机框架(MOFs)是非常有前景的多功能材料,在化学探针、光发射器件以及生物医学领域均有重要的理论和应用价值。MOFs由于其结构可预测性、良好的微环境等优点,为发光体的引入并形成固态发光材料提供了独一无二的平台。引入发光体的方法主要有镧系金属的引入、发光配体引入以及发光客体引入三种方法。但是,将有机荧光染料引入到MOFs孔道中仍是一个非常大的挑战。因为,在MOFs合成过程中引入有机染料往往会影响金属与有机配体的配位,从而干扰MOFs的形成。而在MOFs合成后,通常只能通过物理吸附来引入有机染料,这就大大降低了发光MOFs的稳定性。本论文基于荧光标记技术,选用常用的荧光标记染料异硫氰基荧光素(FITC),分别对中性类和羧酸类MOFs进行后合成修饰,并对不同的后修饰MOFs性质极其在水溶液中金属识别和吸附中的应用做了进一步的研究。本论文第一部分是以3-氨基-4,4’-联吡啶和4,4’,4”-苯-1,3,5-三-苯甲酸苯作为有机配体与硝酸锌自组装,得到了一种新型的带有氨基官能团的三维大孔MOF晶体：BTPY-NH2。单晶结构检测发现,其窗口和空腔直径分别达到14和27A,空腔占总体积的81.2%。通过核磁、UV-Vis、荧光显微镜以及共聚焦激光显微镜等手段表征,证实了FITC的成功修饰,修饰率达到wt%=5-10%。对修饰后MOF在金属识别中的应用进行了研究,发现其对Ag+检测具有很好的选择性和灵敏性,检测限达到0.1ppm。并探索了MOFs在吸附分离Ag+中的应用,ICP检测显示吸附率达到70%。表明这种发光材料在污水排放监测和饮用水净化领域具有潜在的应用价值。本论文第二部分是选用已报道的两种基于2-氨基对苯二甲酸为配体,具有不同空腔和窗口大小的MOFs:NH2-MIL-125(Ti)和UMCM-1-NH2,用FITC对该MOF进行后合成修饰。证实了合适的空腔和窗口大小对于MOF成功后修饰的重要性。NH2-MIL-125(Ti)由于本身窗口小的限制(5A),FITC修饰率不高,修饰率仅为wt%=1.36%。UMCM-1-NH2由于具有较大的窗口尺寸(12A),修饰率达到了wt%=29%。对修饰后的NH2-MIL-125(Ti)在金属识别中的应用进行了研究,发现其对Hg2+和Ag+都具有很好的荧光淬灭响应,尤其是Hg2+,检测限达到了0.3ppm。此外,它对二价金属离子也有较弱的荧光淬灭响应,而对一价金属离子基本没有响应,这可能是由于配体中羧酸阴离子与硫脲识别位点共同作用产生的。更多还原

【Abstract】 Luminescent MOFs are very promising multifunctional materials for chemical sensors, light-emitting devices, and biomedicine. As MOFs have a degree of structural predictability and the well-defined environments for luminophores in crystalline forms, they offer unique platform for the development of solid-state luminescent materials. Generally, luminescence can arise from organic ligands, metals, and guest molecules. However, the incorporation of fluorescent dyes within the stable pores of MOFs is still a big challenge, because most of the bright luminophores are not compatible with the MOF synthetic conditions or exhibiting groups interfere with the formation of the desired MOFs. Inspired from fluorescent labeling technology, the common labeling dye, Fluorescein Isothiocyanate (FITC), was selected to post-modify MOFs self-assembled by neutral ligands or acidic ligands. The application of modified MOFs in metal-ions detection and adsorption was also investigatedA new metal-organic framework (BTPY-NH2) with amino groups and neutral ligands was obtained. Single-crystal X-ray diffraction revealed that the largest pore and window sizes of BTPY-NH2were about27A and14A in diameter respectively, the solvent accessible volume accounted for81.2%of the crystal volume. After post modification of BTPY-NH2with fluoresceinisothiocyanate (FITC), FITC@BTPY-NH2was obtained, the wt%of FITC was measured about5-10%. Through studying the recognition ability and adsorption of FITC@BTPY-NH2for metal ions, it indicated that modified MOF can sense Ag+in aqueous solution selectively.The detection limit was0.1ppm.Reported metal-organic frameworks:NH2-MIL-125(Ti) and UMCM-1-NH2based on2-aminoterephthalic acid were selected. The window sizes of them were about5A and12A in diameter respectively. After modified by FITC, the FITC contents in both MOFs were measured about wt%=1.4%and29%respectively. Furthermore, the recognition ability of FITC@NH2-MIL-125(Ti) for metal ions was studied. It showed that the modified MOF can detect sensentively Ag+and Hg2+in aqueous solution. The detection limits of Ag+and Hg2+were1.3ppm and0.3ppm respectively.更多还原