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Updated: May 20, 2026
20:28
A Toolkit to Enable Hydrocarbon Conversion in Aqueous Environments
Published on: October 2, 2012
安定したアルケンは,非常に長い炭素-炭素結合を含んでいる
Andrey A Fokin1, Lesya V Chernish, Pavel A Gunchenko
1Department of Organic Chemistry, Kiev Polytechnic Institute, pr. Pobedy 37, 03056 Kiev, Ukraine. aaf@xtf.kpi.ua
Journal of the American Chemical Society
|July 28, 2012
まとめ
極めて安定した炭化水素二重体と,非常に長い炭素-炭素結合を合成した. 内分子ヴァン・デル・ワールズ力は,これらの異常な結合を安定させ,従来の化学理論に挑戦します.
科学分野:
- 有機化学 オーガニック・ケミストリー
- コンピューティング・ケミストリー
- マテリアルサイエンス 材料科学
背景:
- 金属誘導による三次性ダイアモンド型ブロミドの結合により,ステリカルに阻害された炭化水素二重体が得られます.
- これらのダイマーは,異常に長い中央炭素-炭素 (C-C) 結合 (最大1.71 Å) と高熱安定性 (>200 °C) を表しています.
- この安定性は,典型的なC-C結合の長さ-強さの相関関係と矛盾しています.
研究 の 目的:
- 非常に混雑した炭化水素二重体の構造的および動的性質を調査する.
- ダイヤモンド型系における長いC−C結合の例外的な安定性に寄与する要因を理解する.
- これらのユニークな結合シナリオを記述する様々な密度関数理論 (DFT) 方法のパフォーマンスを評価する.
主な方法:
- 金属誘導結合による三次性ダイヤモンド型ブロミドの合成による炭化水素ジマー.
- 温度変数核磁共鳴 (NMR) スペクトロスコーピー ((1) H と (13) C) で,C−C結合の回転ダイナミクスを研究する.
- 多数のDFT関数とベースセットを使用して,幾何学と回転障壁をモデル化するための計算分析.
主要な成果:
- 2-(1-ダイアマンチル) [121]テトラマンタンなどの合成ダイマーには,分子内ヴァン・デル・ワールスの引き寄せによって安定した非常に長いC-C結合があります.
- C−C結合の回転障壁は,ダイアモンド形表面の形状によって大きく変化する (733 kcal mol ((-1)) である.
- 分散補正されたDFT関数は,実験的幾何学を正確に予測します;ほとんどのDFT関数は,エラーキャンセルによる回転障壁を捕捉します.
- コンピューティングによる研究により,分散力によってのみ安定化されるラジカルダイマーおよびポリマーを作成する可能性があることが示唆されています.
結論:
- 内部分子ヴァン・デル・ワールズ力は,ステリカルに混雑したダイアモンド型二次体における異常に長いC-C結合の安定化に不可欠である.
- ダイヤモンド型CH表面の幾何学は,C−C結合の回転力学と関連するエネルギー障壁を決定する.
- DFTの方法,特に分散修正を含む方法は,これらの複雑な結合状況を正確にモデル化するために不可欠です.
- 観察された原理は,分散力に基づいて,過激なポリマーを含む新しい材料の設計を可能にすることができます.
関連する概念動画
02:18Constitutional Isomers of Alkanes
Organic compounds of the same molecular formula can have different structural formulas called constitutional isomers, and the phenomenon is known as constitutional isomerism. Alkanes with four or more carbons showing multiple structures with the same molecular formula thereby exhibit constitutional isomerism.
The linear isomer of an alkane is prefixed by the term “n”; hence a linear isomer of pentane is known as n-pentane. Based on the type of branching, some of the branched isomers are given...
The linear isomer of an alkane is prefixed by the term “n”; hence a linear isomer of pentane is known as n-pentane. Based on the type of branching, some of the branched isomers are given...
02:23Structure of Alkanes
The formation of carbon-carbon bonds leading to the creation of the carbon chain is the basis of organic chemistry. August Kekulé and Archibald Scott Couper independently developed this idea of carbon chain formation.
Hydrocarbons are the simplest organic compounds composed of carbons and hydrogens. Based on the bond order between carbons, the hydrocarbons are further classified into alkanes, alkenes, and alkynes.
Alkanes are the simplest hydrocarbons with sp3 hybrid carbon atoms. These sp3...
Hydrocarbons are the simplest organic compounds composed of carbons and hydrogens. Based on the bond order between carbons, the hydrocarbons are further classified into alkanes, alkenes, and alkynes.
Alkanes are the simplest hydrocarbons with sp3 hybrid carbon atoms. These sp3...
02:47Structure and Bonding of Alkenes
Olefins, which are unsaturated hydrocarbons containing one or more carbon–carbon double bonds, are broadly divided into alkenes and cycloalkenes. The general chemical formula of an alkene is CnH2n.
Doubly bonded carbons are sp2 hybridized and have a trigonal planar geometry. The double bond is composed of a σ bond formed by the overlap of hybrid orbitals and a π bond produced by the lateral overlap of unhybridized 2p orbitals on both the carbons. Each carbon atom is bonded to two hydrogen atoms...
Doubly bonded carbons are sp2 hybridized and have a trigonal planar geometry. The double bond is composed of a σ bond formed by the overlap of hybrid orbitals and a π bond produced by the lateral overlap of unhybridized 2p orbitals on both the carbons. Each carbon atom is bonded to two hydrogen atoms...
02:14Combustion Energy: A Measure of Stability in Alkanes and Cycloalkanes
The low reactivity in alkanes can be attributed to the non-polar nature of C–C and C–H σ bonds. Alkanes, therefore, were initially termed as “paraffins,” derived from the Latin words: parum, meaning “too little,” and affinis, meaning “affinity.”
Alkanes undergo combustion in the presence of excess oxygen and high-temperature conditions to give carbon dioxide and water. A combustion reaction is the energy source in natural gas, liquified petroleum gas (LPG), fuel oil, gasoline, diesel fuel, and...
Alkanes undergo combustion in the presence of excess oxygen and high-temperature conditions to give carbon dioxide and water. A combustion reaction is the energy source in natural gas, liquified petroleum gas (LPG), fuel oil, gasoline, diesel fuel, and...
02:22Nomenclature of Alkanes
In the late 19th-century, the number of new chemical compounds discovered increased tremendously. Hence, the necessity arose to develop a naming system for the systematic nomenclature of these newly discovered compounds. IUPAC (International Union for Pure and Applied Chemistry), established in 1919, sets rules for the nomenclature.
The alkane nomenclature considers the length of the carbon chain, the number, and the location of the substituent to arrive at its systematic name. The IUPAC...
The alkane nomenclature considers the length of the carbon chain, the number, and the location of the substituent to arrive at its systematic name. The IUPAC...
02:33Physical Properties of Alkanes
Alkanes are nonpolar molecules due to the presence of only carbon and hydrogen atoms. The electronegativity difference between carbon and hydrogen is minimal, and hence alkanes have a zero dipole moment. This leads to the presence of only dispersion forces between the molecules. The strength of dispersion forces is dependent on the surface area of the molecules on which they act. Since the surface area increases with the molecular length for straight-chain alkanes, the dispersion forces also...