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3. （2017-05-04）JACS发表邓鹤翔教授团队成果揭示多组分MOF催化机理

（2017-05-04）JACS发表邓鹤翔教授团队成果揭示多组分MOF催化机理

近年来多组分金属有机框架材料（MTV-MOF）的发现为MOF领域提供了一个引入多个功能基团或金属基元的方法，相比单组分简单物理混合，多组分的协同能提供更为优良的性能（Science, 2010, 327, 846），并且有可能未来在分子尺度上实现更为复杂的有序操作，如接力等。但是由于MTV-MOFs中多组分基团通常处于等效的晶体学位置，通过X射线衍射手段很难破译其组分三维分布。虽然此前已有方法区分功能基团的分布，然而节点金属的混合及金属基元分布一直以来难以解析。

邓鹤翔教授团队通过组合包含5类金属的不同次级构筑单元（SBU-metals）和包含6类金属或非金属的不同有机配体（linker-metals），合成了一系列同拓扑的27种单组份MOFs（化学通式为(M₃O)₂(TCPP-M)₃）和9种同拓扑多组分MTV-MOFs （化学通式为[(M1)_x(M2)_3-xO)₂(TCPP-M)₃]）。通过改变单组份MOFs中无机簇中的金属和配体金属, 组合出的(Mn₃O)₂(TCPP-Ni)₃具备极高的光催化氧化1,5-二羟基萘(DHN)活性（转化速率达到81.5×10^-2 h^-1）。更重要的是，研究团队借助光谱学首次破译了MTV-MOFs中的两种金属组分分布类型，并且研究了这两种金属组分分布与MOFs能带结构和催化效率的关系。团队成员创造性地应用X射线光电子能谱（XPS），紫外可见漫反射光谱（UV-vis DRS）以及X射线吸收精细结构谱（XANES和EXAFS）、电子顺磁共振谱（EPR）、穆斯堡尔谱等手段揭示这些金属化学环境的细微差异。首次解析了金属的空间排布，揭示了金属有两种不同的组合模式：区域形式和交错混合。研究发现那些有着交错混合排列的多金属MTV-MOF在光催化反应中有着更为优异的性能。如MTV-MOF (Mn_1.77Ni_1.23O)₂(TCPP-Ni)₃表现出高达1.03 h^-1的转化速率。这一发现进一步拓宽了MTV-MOF的合成和表征手段。该工作近日在美国化学会志(Journal of the American Chemical Society，JACS)上发表，论文题为“Deciphering the Spatial Arrangement of Metals and Correlation to Reactivity in Multivariate Metal-Organic Frameworks”(DOI: 10.1021/jacs.6b08724)。

2014级博士生刘琦为论文第一作者，化学院大型仪器中心丛恒将副研究员参与此项研究，邓鹤翔教授为该文章的通讯作者。该工作得到了国家自然科学基金和基金委重大研究计划重点项目的支持。上海光源（SSRF）BL14W、BL15U线站对X射线吸收精细结构谱，BL17U1线站对X射线微晶衍射提供有力的支持。

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原文链接 http://pubs.acs.org/doi/abs/10.1021/jacs.6b08724

邓鹤翔教授课题组 http://hdeng.whu.edu.cn

English Version:

The Whole is Better Than The Sum of Its Parts

-Hexiang Deng’s recent research published on JACS

One of the big potentials in the MOF field is that the extend framework can hold multiple functional groups (eg. mechanic moieties) closely to each other so that they can operate either in parallel or even in sequence. Such multi-variate MOFs (MTV-MOFs) have identical structure to the original MOF crystallgraphically, thus the spatial arrangement of multiple components in MTV-MOFs are extremely hard to decipher. In the past two years, a research team in Wuhan University lead by Hexiang Deng synthesized a series of thirty-six porphyrin based MOFs with various metals. They creatively applied X-ray photoelectron spectroscopy (XPS), ultraviolet-visible diffuse reflectance spectra (UV-vis DRS) to reveal the subtle difference in the chemical environment of these metals. Through detailed analysis, the researchers deciphered, for the first time, the metal spatial arrangement found that the metals exist in the form of either domains or well-mixed arrangement. They also revealed that those MTV-MOFs with well-mixed metals rather metals forming domains, perform significantly better in photocataytic reaction. This general method provides new ways to rationalize the synthesis and characterization of MTV-MOF and published on Journal of the American Chemical Society (JACS) with the title “Deciphering the Spatial Arrangement of Metals and Correlation to Reactivity in Multivariate Metal-Organic Frameworks” (DOI: 10.1021/jacs.6b08724). Qi Liu and Hengjiang Cong are the main contributing authors for this research. This research is supported by the 1000 Talent Plan of China, National Natural Science Foundation of China (21471118) and National Key Basic Research Program of China (2014CB239203). X-ray Adsorption Fine-Structure (XAFS) spectra were collected at beamlines BL14W and BL15U, and Microcrystal X-ray Diffraction experiments were performed at beamline BL17U1 of Shanghai Synchrotron Radiation Facility (SSRF).