从Fe ((TPP) 催化的氧化中转移O原子
1Department of Chemistry, University of California, Irvine, California, 92697-2025, USA.
Journal of the American Chemical Society
|July 18, 2001
概括
铁四甲氨酸 (NO-Fe(TPP)) 与氧化 (NO) 气体的反应形成了一个短暂的N--N-合添加物. 这种中间体是理解NO-Fe (TPP) 转化和潜在N2O生产的关键.
科学领域:
- 无机化学 无机化学 无机化学
- 有机金属化学 有机金属化学
- 反应机制的反应机制
背景情况:
- 铁甲 (NO-Fe(TPP)) 在协调化学中很重要.
- 了解NO-Fe (TPP) 与氧化 (NO) 的反应途径对于催化应用至关重要.
研究的目的:
- 为了阐明NO-Fe的反应机制 (TPP) 与NO气体的低压.
- 识别关键的中间体及其在转型过程中的作用.
- 调查催化氧化 (N2O) 生产的潜力.
主要方法:
- 用光谱分析,包括红外光谱,来识别短暂的中间体.
- 用同位素标记实验 (14N/15N) 来追踪原子转移和合.
- 基于实验观测,开发了动力学研究和机械学建议.
主要成果:
- 鉴定出一种短暂的N-N-合 (NO) 2 adduct中间体.
- 观察到NO (NO2) Fe (TPP) 的形成,这表明涉及自由NO2.2的途径.
- 通过使用具有竞争力的氧原子接受器 (PPh3) 实现了N2O的催化生产.
- 交叉标记实验证实了中间体中氧原子的等价性.
- 红外光谱学证实了短暂的,对同位素敏感的波段,表明中间体.
结论:
- 反应通过一个独特的N-N合的引介质进行.
- 一个拟议的机制解释了酸盐和N2O的形成.
- 从中间体转移氧原子是高效的,涉及相当的氧原子.
- 该研究提供了对NO-Fe (TPP) 的反应性和潜在的催化循环的见解.
相关概念视频
03:20Nuclear 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...
02:44Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.
02:04Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids
Diols are compounds with two hydroxyl groups. In addition to syn dihydroxylation, diols can also be synthesized through the process of anti dihydroxylation. The process involves treating an alkene with a peroxycarboxylic acid to form an epoxide. Epoxides are highly strained three-membered rings with oxygen and two carbons occupying the corners of an equilateral triangle. This step is followed by ring-opening of the epoxide in the presence of an aqueous acid to give a trans diol.
01:27π Electron Effects on Chemical Shift: Overview
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0, resulting in...
01:14π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds
In aromatic compounds, such as benzene, the circulation of (4n + 2) π-electrons sets up a diamagnetic or diatropic ring current around the perimeter of the molecule. This current induces a magnetic field that opposes the external field inside the ring and reinforces it on the outside. The protons in benzene are deshielded and exhibit high chemical shifts in the range 6.5–8.5 ppm. The shielding effect at the center of the ring is evident in complex aromatic molecules, such as annulenes. In...
01:06Nuclear Overhauser Enhancement (NOE)
Irradiation of a spin-active nucleus causes an increase or decrease in the signal intensity of neighboring nuclei that are not necessarily chemically bonded or involved in J-coupling. This phenomenon, called the nuclear Overhauser enhancement (NOE), results from through-space interactions between the nuclear spins. The NOE effect decreases with increasing internuclear distance and is generally not observed beyond 4 angstroms. In NOE, dipole-dipole interactions between neighboring spin-active...