シラン酸化機構の量子化学的調査
1Department of Chemistry, Grinnell College, Grinnell, Iowa 50112, USA. mader_mary@lilly.com
Journal of the American Chemical Society
|July 18, 2001
まとめ
量子化学計算により,オルガノシランの酸化メカニズムが明らかになった. 溶解は反応経路を大幅に変化させ,アルコールの形成のために二塩基メタンやメタノールなどの溶媒に過酸化アニオンの添加を好む.
科学分野:
- 有機金属化学 有機金属化学
- コンピューティング・ケミストリー
- 反応メカニズム研究 反応メカニズム研究
背景:
- オーガノシランは,有機合成における汎用的な前駆体である.
- 酸化過酸化は,オルガノシランの機能化のための重要な変換である.
- 反応メカニズムの理解は,合成経路の最適化に不可欠です.
研究 の 目的:
- オルガノシランをアルコールに過酸化酸化する様々なメカニズムを比較する.
- これらの反応経路に対する溶解の影響を調査する.
- アニオンペンタコーディネートシリケート中間物質の役割を明らかにする.
主な方法:
- 反応経路をモデル化するために,量子化学計算を用いた.
- 溶媒効果をシミュレートするためにPCM溶解モデルが使用されました.
- 異なるメカニズム的経路は,それらのエネルギー的な好意性のために分析されました.
主要な成果:
- 反応は常にアニオン性,ペンタコーディネート性シリケート種を通過する.
- 溶解は,ガス相計算と比較して反応プロフィールに大きな影響を及ぼします.
- CH(2)Cl(2) とMeOHでは,最も有利な経路は,過酸化アニオンをフッ素シランに添加し,それに協調した移行と水酸化物解離が続く.
- ガス相では,ペンタコーディネートフローロシリケートへのH(2) O(2) の協調的な加法-移住も,妥当なメカニズムである.
結論:
- 溶解効果は,オルガノシランペロキシド酸化の好ましいメカニズムを決定する上で重要である.
- 特定されたメカニズムは,オルガノシランからアルコールの合成に関する貴重な洞察を提供します.
- 計算化学は,複雑な反応経路を解剖するための強力なツールとして機能します.
関連する概念動画
01:24Redox Reactions
Oxidation-reduction or redox reactions involve the transfer of electrons from one molecule or atom to another. When an atom gains an electron, another atom must lose an electron, meaning oxidation and reduction must occur together. Since the redox occurs in pairs, the atom that gets oxidized is also called the reducing agent or reductant, and the atom that is reduced is also called the oxidizing agent or oxidant. A straightforward way to remember the definitions of oxidation and reduction is...
03:06Reaction Mechanisms
Chemical reactions often occur in a stepwise fashion, involving two or more distinct reactions taking place in a sequence. A balanced equation indicates the reacting species and the product species, but it reveals no details about how the reaction occurs at the molecular level. The reaction mechanism (or reaction path) provides details regarding the precise, step-by-step process by which a reaction occurs.
For instance, the decomposition of ozone appears to follow a mechanism with two steps:
For instance, the decomposition of ozone appears to follow a mechanism with two steps:
03:00Electrolysis
In a galvanic cell, the electrical work is done by a redox system on its surroundings as electrons produced by the spontaneous redox reactions are transferred through an external circuit. Alternatively, an external circuit does work on a redox system by imposing a voltage sufficient to drive an otherwise nonspontaneous reaction in a process known as electrolysis. For instance, recharging a battery involves the use of an external power source to drive the spontaneous (discharge) cell reaction in...
01:46Oxidative Cleavage of Alkenes: Ozonolysis
In ozonolysis, ozone is used to cleave a carbon–carbon double bond to form aldehydes and ketones, or carboxylic acids, depending on the work-up.
Ozone is a symmetrical bent molecule stabilized by a resonance structure.
Ozone is a symmetrical bent molecule stabilized by a resonance structure.
01:19Oxidation and Reduction of Organic Molecules
Energy production within a cell involves many coordinated chemical pathways. Most of these pathways are combinations of oxidation and reduction reactions, which occur at the same time. An oxidation reaction strips an electron from an atom in a compound, and the addition of this electron to another compound is a reduction reaction. Because oxidation and reduction usually occur together, these pairs of reactions are called redox reactions.
The removal of an electron from a molecule, results in a...
The removal of an electron from a molecule, results in a...
01:26Oxygenic Photosynthesis
Oxygenic photosynthesis is a fundamental process in which light energy is harnessed to drive the oxidation of water, leading to the production of molecular oxygen (O₂), adenosine triphosphate (ATP), and nicotinamide adenine dinucleotide phosphate (NADPH). This process is essential for sustaining aerobic life on Earth and is primarily carried out by cyanobacteria, algae, and plants. The core of oxygenic photosynthesis lies in the thylakoid membranes, where chlorophyll pigments facilitate light...