当前位置: X-MOL 学术Inorg. Chem. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Development of Isostructural Porphyrin–Salen Chiral Metal–Organic Frameworks through Postsynthetic Metalation Based on Single-Crystal to Single-Crystal Transformation
Inorganic Chemistry ( IF 4.3 ) Pub Date : 2018-01-08 00:00:00 , DOI: 10.1021/acs.inorgchem.7b02631
Jiawei Li 1 , Yamei Fan 1 , Yanwei Ren 1 , Jianhua Liao 2 , Chaorong Qi 1 , Huanfeng Jiang 1
Affiliation  

The development of well-defined multimetallic porous metal–organic frameworks (MOFs) will add a new dimension to the application of MOF catalysis. From this perspective, the understanding and tailoring of the catalytic metal sites in MOFs are key fundamental challenges that could reveal the intrinsic potential of these materials. In this work, a series of porphyrin–salen chiral MOFs (ps-CMOFs 2–7) have been synthesized through postsynthetic metalation (PSMet) of the parent ps-CMOF via single-crystal to single-crystal transformation. Crystal structures of these ps-CMOF analogues revealed the same topological structure but varied metal entities compared to those of the parent framework. Note that the PSMet process involves three methods involving cation exchange at the nodes, cation exchange at the metalated porphyrin, and cation addition at the free porphyrin, which has been systematically investigated using single-crystal X-ray diffraction and other physicochemical methods. The N2 adsorption tests, thermogravimetric analysis, and powder X-ray diffraction of 2–7 showed curves or patterns similar to those of 1, indicating the maintenance of the crystallinity, porosity, and thermal stability of the framework during the PSMet process. In addition, 2–7 showed distinctly improved adsorption capacities and isosteric heats of adsorption (Qst) for CO2 compared to those of their parent counterpart. Lastly, as a representative example of the ps-CMOF catalytic platform, 5 proved to be an efficient recyclable heterogeneous catalyst for the asymmetric addition reaction of CO2 with epoxides under mild conditions. Furthermore, because of the constrained chiral environment within ps-CMOF, the enantioselectivity of this reaction appears to be dependent on substrate size.

中文翻译:

基于单晶到单晶转变的后合成金属化方法开发同构卟啉-沙仑手性金属-有机骨架

定义明确的多金属多孔金属有机骨架(MOF)的开发将为MOF催化的应用增加新的维度。从这个角度出发,对MOF中催化金属位点的理解和定制是可能揭示这些材料的内在潜力的关键基本挑战。在这项工作中,一系列的卟啉-salen手性MOF(ps-CMOF 2–7)是通过单晶到单晶转变通过母体ps-CMOF的后合成金属化(PSMet)合成的。这些ps-CMOF类似物的晶体结构与母构架相比具有相同的拓扑结构,但金属实体却不同。请注意,PSMet过程涉及三种方法,包括结点处的阳离子交换,金属化卟啉处的阳离子交换和游离卟啉处的阳离子添加,这已使用单晶X射线衍射和其他物理化学方法进行了系统研究。2-7的N 2吸附测试,热重分析和粉末X射线衍射显示的曲线或图案与1相似。表示在PSMet过程中保持了框架的结晶度,孔隙率和热稳定性。此外,2–7与母体相比,对CO 2的吸附能力和等规吸附热(Q st)明显提高。最后,作为ps-CMOF催化平台的代表实例,证明5是温和条件下CO 2与环氧化物的不对称加成反应的有效可循环异构催化剂。此外,由于ps-CMOF中手性环境的限制,该反应的对映选择性似乎取决于底物的大小。
更新日期:2018-01-08
down
wechat
bug