通过二化物激活二氧化物:制备和表征d4正方形平面复合体
Miguel A Esteruelas1, Francisco J Modrego, Enrique Oñate
1Departamento de Química Inorgánica-Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza-Consejo Superior de Investigaciones Científicas, 50009-Zaragoza, Spain. maester@posta.unizar.es
Journal of the American Chemical Society
|October 30, 2003
概括
奥斯化合物OsH2Cl2(PiPr3)2与氧气反应,形成Os(VI) 二氧化物种. 进一步的减少产生了一种罕见的Os(IV) 二氧化物化合物,展示了新的O=O键激活和d4正方形平面化学.
科学领域:
- 有机金属化学 有机金属化学
- 无机化学 无机化学 有机化学
- 奥斯催化剂的催化方法
背景情况:
- 奥斯复合物以其多样化的反应性而闻名.
- 在二氧化物中O=O双键的直接激活是化学中具有挑战性但至关重要的转化.
- 方形平面d4金属复合体相对罕见,并表现出独特的电子特性.
研究的目的:
- 为了研究OsH2Cl2(PiPr3) 2与分子氧的反应.
- 为了合成和表征新的奥斯二氧化物种.
- 探索将Os(VI) 二氧化物复合物降解为Os(IV) 类似物.
主要方法:
- 暴露于空气和纯氧中的OsH2Cl2 ((PiPr3) 2).
- Os(VI) 滴氧物种与n-丁 (n-BuLi) 的反应.
- 由此产生的化合物的表征.
主要成果:
- 实现了直接的O=O双键激活,产生了Os(VI) 二氧化化合物OsO2Cl2(PiPr3) 2.2.
- 用n-BuLi减少Os(VI) 种类,可以获得新的Os(IV) 二氧化衍生物OsO2(PiPr3) 2.2.
- Os(IV) 产物是d4正方形平面复合体的一个罕见例子.
结论:
- OsH2Cl2 ((PiPr3) 2) 很容易经历与氧的直接O=O键激活.
- 合成了一种新的Os(IV) 双氧复合物,OsO2(PiPr3) 2,突出了罕见的d4正方形平面几何.
- 这项研究扩大了对的反应性和不同寻常的氧化状态和几何形状的合成的理解.
相关概念视频
Newman Projections
Different notations are used to represent the three-dimensional structure of molecules on two-dimensional surfaces. One of the most commonly used representations is the dash-wedge formula. The dashed wedges, solid wedges, and the plane lines indicate the groups situated behind the plane, coming out of the plane, and in the plane, respectively.
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as conformers.
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as conformers.
Photochemical Electrocyclic Reactions: Stereochemistry
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
The Diels–Alder reaction is one of the robust methods for synthesizing unsaturated six-membered rings. The reaction involves a concerted cyclic movement of six π electrons: four π electrons from the diene and two π electrons from the dienophile.
Diels–Alder Reaction: Characteristics of Dienes
The Diels–Alder reaction brings together a diene and a dienophile to form a six-membered ring. Both components have unique characteristics that influence the rate of the reaction.
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is more stable, the...
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is more stable, the...
[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement
The Cope rearrangement is classified as a [3,3] sigmatropic shift in 1,5-dienes, leading to a more stable, isomeric 1,5-diene. The reaction involves a concerted movement of six electrons, four from two π bonds and two from a σ bond, via an energetically favorable chair-like transition state.


