基基甲基催化剂的Mo NMR签名
Zachariah J Berkson1, Ran Zhu2, Christian Ehinger1
1Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich CH-8093, Switzerland.
Journal of the American Chemical Society
|May 31, 2023
概括
基于的氧化催化剂因制备方法的不同而表现出不同的转化活性. 先进的Mo NMR揭示了与电子结构和可还原性相关的独特活性位点,增强了催化性能.
科学领域:
- 不同质的催化
- 表面有机金属化学
- 固态核磁共振光谱
背景情况:
- 氨酸转化是有机合成和聚合物化学中的一个关键反应.
- 支持的氧化是广泛使用的催化剂,但它们的活性对制备敏感.
- 了解活性位点的性质和分布是优化催化剂性能的关键.
研究的目的:
- 研究制备方法对氧化物催化剂的活性部位的影响.
- 将位的结构和电子性质与它们在基转化中的催化活性相关联.
- 使用先进的固态Mo NMR来描述不同的物种.
主要方法:
- 使用浸和表面有机金属化学 (SOMC) 合成氧化催化剂.
- 通过FTIR,UV-vis,MoK边缘X射线吸收光谱和高场Mo NMR进行表征.
- 解释NMR参数和电子结构的第一原则计算.
主要成果:
- 浸和SOMC方法都产生主要是孤立的Mo dioxo位点,但分布不同.
- 与同样负载的浸催化剂相比,SOMC衍生的催化剂在烯酸转化中表现出1.5至2.0倍的活性.
- 核磁共振可分辨出四个不同的二氧位点,具有特定的脱信号,与更高的可减少性和活性相关.
结论:
- 催化剂制备对表面位的分布及其催化性能产生重大影响.
- NMR的化学转移对局部应变和协调敏感,为电子结构提供了洞察力.
- 电子特性,特别是LUMO能量,决定了支持的位的可降解性和反应性.
更多相关视频
07:47Reverse Microemulsion-mediated Synthesis of Monometallic and Bimetallic Early Transition Metal Carbide and Nitride Nanoparticles
Published on: November 27, 2015
10.9K
08:25Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks MOFs
Published on: January 17, 2020
7.3K
相关概念视频
Olefin Metathesis Polymerization: Overview
2.2K
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists...
2.2K
Cycloaddition Reactions: MO Requirements for Thermal Activation
3.6K
Thermal cycloadditions are reactions where the source of activation energy needed to initiate the reaction is provided in the form of heat. A typical example of a thermally-allowed cycloaddition is the Diels–Alder reaction, which is a [4 + 2] cycloaddition. In contrast, a [2 + 2] cycloaddition is thermally forbidden.
3.6K
Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
2.0K
Acyclic diene metathesis polymerization or ADMET polymerization involves cross-metathesis of terminal dienes, such as 1,8-nonadiene, to give linear unsaturated polymer and ethylene. As ADMET is a reversible process, the formed ethylene gas must be removed from the reaction mixture to complete the polymerization process.
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
2.0K
