Tp'Rh ((CNneopentyl)) ((CH2X) Hにおけるロジウム-炭素結合エネルギー:M-C結合における安定化効果を定量化する
Yunzhe Jiao1, Meagan E Evans, James Morris
1Department of Chemistry, University of Rochester, Rochester, New York 14627, United States.
Journal of the American Chemical Society
|April 25, 2013
まとめ
研究者らは,代用メチルロジウム複合体を合成し,その反応性を研究した. Rh-C結合エネルギーは,C-H結合強度と相関し,オレフィン挿入反応の予測可能なパターンを明らかにした.
科学分野:
- 有機金属化学 有機金属化学
- 協調化化学について
- ロジウム複合体とは
背景:
- ロジウム複合体の置換メチル誘導体は,触媒作用において重要である.
- その反応性に影響を与える要因を理解することは,新しい合成方法の開発に不可欠です.
研究 の 目的:
- Tp'Rh (((CNneopentyl)) ((CH2X) H.の一連の置換メチル誘導体を合成するために.
- 還元性除去と金属-炭素結合の強さを調査する.
- これらの特性をC−H結合強度と相関させ,オレフィン挿入の好みを予測する.
主な方法:
- 光分解または炭化水素交換による合成.
- NMRスペクトロスコーピー,元素分析,X線結晶学を用いた特徴化.
- 運動技術とDFT計算を使用してRh-C結合エネルギーの決定.
主要な成果:
- すべてのデリバティブの単一の製品の成功合成.
- すべての化合物のクリーン・リダクティブ・エミリテーションが観察されました.
- Rh-C結合エネルギーとC-H結合強さの間の2つの線形相関が発見されました.
- DFTの計算は実験結果とよく一致していた.
結論:
- β-C-H結合の強さは,オレフィン挿入製品の好みを予測する.
- α置換Rh-CH2X誘導体のRh-C結合強度は,実験結果と一致する傾向を示しています.
さらに関連する動画
関連する概念動画
02:30Stability of Substituted Cyclohexanes
This lesson discusses the stability of substituted cyclohexanes with a focus on energies of various conformers and the effect of 1,3-diaxial interactions.
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
01:18Aromatic Hydrocarbon Cations: Structural Overview
Cycloheptatriene is a neutral monocyclic unsaturated hydrocarbon that consists of an odd number of carbon atoms and an intervening sp3 carbon in the ring. The three double bonds in the ring correspond to 6 π electrons, which is a Huckel number, and therefore satisfies the criteria of 4n + 2 π electrons. However, the intervening sp3 carbon disrupts the continuous overlap of p orbitals. As a result, cycloheptatriene is not aromatic.
Removing one hydrogen from the intervening CH2 group with both...
Removing one hydrogen from the intervening CH2 group with both...
02:10Carbocations
Carbocations are one of the reaction intermediates formed during several nucleophilic substitutions or elimination reactions. A carbocation is an electron-deficient species with the central carbon atom having six electrons and three bonded atoms. The central carbon in a carbocation is sp2 hybridized with trigonal planar geometry. It has an empty p orbital perpendicular to the plane of the structure that can accept electrons. Thus, carbocations act as strong electrophiles and may react with any...
02:49Bond Energies and Bond Lengths
Stable molecules exist because covalent bonds hold the atoms together. The strength of a covalent bond is measured by the energy required to break it, that is, the energy necessary to separate the bonded atoms. Separating any pair of bonded atoms requires energy — the stronger a bond, the greater the energy required to break it.
01:08Spin–Spin Coupling Constant: Overview
In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
02:38Electrophilic Addition to Alkynes: Halogenation
Introduction
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.