在[Ni(P(R) 2N(R') 2) 2) 2) 2) 2+生产和氧化催化剂中的质子输送和去除
Molly O'Hagan1, Ming-Hsun Ho, Jenny Y Yang
1Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, P.O. Box 999, K2-57, Richland, Washington 99352, USA.
Journal of the American Chemical Society
|October 18, 2012
概括
质子定位是基于的催化剂的关键. 最活跃的形式需要特定的质子放置,而低效的质子转移可以限制生产和氧化反应中的催化速度.
科学领域:
- 电化学 电化学 电化学
- 催化剂是一种催化剂.
- 有机金属化学 有机金属化学
背景情况:
- 与1,5-diaza-3,7-diphosphacyclooctane连接体的复合物被研究用于电催化氧化和生产.
- 质子转移动态对于这些基催化剂的效率至关重要.
研究的目的:
- 阐明质子输送和去除在[Ni(P(R) ((2) N(R') ((2)) ((2))) 2+) 复合物的电催化循环中的作用.
- 了解质子物种的异体化及其对催化活性的影响.
主要方法:
- 对分子间质子交换反应进行了实验和理论研究.
- 分析的重点是三种质子化异构体的异构化:内/内,内/外,外/外.
主要成果:
- 由于质子与中心的最佳接近,endo/endo异构体在催化上是最有效的.
- 异构化速率受到质子输送到复合体或从复合体中移除的限制.
- 立体阻碍有利于动力学上有利的外质子,导致生产力较低的途径.
结论:
- 精确的质子传递和去除对于高效的催化电化学至关重要.
- 影响质子化部位的绝缘因素显著影响催化转换率.
- 机械洞察力为设计改进的生产和氧化催化剂提供了指导.
相关概念视频
Catalysis
The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.
Catalysis
Catalysis influences the rate of chemical reactions by providing an alternative reaction pathway with lower activation energy. A catalyst speeds up a reaction, but it is not consumed during the process. The fundamental principle of catalysis is the ability of a catalyst to alter the reaction mechanism, often introducing a more efficient pathway than the uncatalyzed process.In a catalyzed reaction, the catalyst participates directly in the reaction mechanism. It interacts with reactants to form...
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Nuclear Transmutation
Nuclear transmutation is the conversion of one nuclide into another. It can occur by the radioactive decay of a nucleus, or the reaction of a nucleus with another particle. The first manmade nucleus was produced in Ernest Rutherford’s laboratory in 1919 by a transmutation reaction, the bombardment of one type of nuclei with other nuclei or with neutrons. Rutherford bombarded nitrogen-14 atoms with high-speed α particles from a natural radioactive isotope of radium and observed protons being...
Reduction of Alkenes: Catalytic Hydrogenation
Alkenes undergo reduction by the addition of molecular hydrogen to give alkanes. Because the process generally occurs in the presence of a transition-metal catalyst, the reaction is called catalytic hydrogenation.
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the surface of...
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the surface of...
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...


