Collins Sean M, Kepaptsoglou Demie M, Butler Keith T, Longley Louis, Bennett Thomas D, Ramasse Quentin M, Midgley Paul A
Department of Materials Science and Metallurgy , University of Cambridge , 27 Charles Babbage Road , Cambridge CB3 0FS , United Kingdom.
SuperSTEM Laboratory, SciTech Daresbury Campus , Daresbury WA4 4AD , United Kingdom.
J Am Chem Soc. 2018 Dec 26;140(51):17862-17866. doi: 10.1021/jacs.8b11548. Epub 2018 Dec 13.
Microstructured metal-organic framework (MOF) glasses have been produced by combining two amorphous MOFs. However, the electronic structure of these materials has not been interrogated at the length scales of the chemical domains formed in these glasses. Here, we report a subwavelength spatially resolved physicochemical analysis of the electronic states at visible and UV energies in a blend of two zeolitic imidazolate frameworks (ZIFs), ZIF-4-Co and ZIF-62-Zn. By combining spectroscopy at visible and UV energies as well as at core ionization energies in electron energy loss spectroscopy in the scanning transmission electron microscope with density functional theory calculations, we show that domains less than 200 nm in size retain the electronic structure of the precursor crystalline ZIF phases. Prototypical signatures of coordination chemistry including d- d transitions in ZIF-4-Co are assigned and mapped with nanoscale precision.
通过结合两种非晶态金属有机框架（MOF）制备出了微结构金属有机框架玻璃。然而，尚未在这些玻璃中形成的化学域的长度尺度上研究这些材料的电子结构。在此，我们报告了对两种沸石咪唑酯框架（ZIF），即ZIF-4-Co和ZIF-62-Zn的混合物在可见光和紫外能量下电子态的亚波长空间分辨物理化学分析。通过将扫描透射电子显微镜中电子能量损失谱的可见光和紫外能量以及芯能级电离能的光谱学与密度泛函理论计算相结合，我们表明尺寸小于200 nm的域保留了前驱体结晶ZIF相的电子结构。ZIF-4-Co中包括d-d跃迁在内的配位化学的典型特征被确定并以纳米级精度进行了映射。
