小分子通过基稳定玻利烯的合作激活
Barsha Chakraborty1, Flora Emilia Basumatary1, Holger Braunschweig2
1Department of Chemical Sciences, Tezpur University, Napaam 784028, Assam, India.
Inorganic chemistry
|June 2, 2023
概括
最近探索的碳稳定型玻利烯在激活强大的E-H键和结合一氧化碳 (CO) 等小分子方面表现有前途. 计算研究揭示了它们在合作性债券分裂和显著连接体相互作用方面的潜力.
科学领域:
- 计算化学的计算化学
- 无机化学 无机化学
- 材料科学 材料科学 材料科学
背景情况:
- 基稳定玻利是含有原子,由易斯基稳定的一种化合物.
- 了解它们的反应性对于开发新的催化过程至关重要.
- 碳稳定玻利代表了这些化合物的较少探索的类别.
研究的目的:
- 为了研究基稳定玻利烯的联结体特性.
- 探索它们在激活强大的E-H键 (E=H,NH2,SiH2Ph,CH3) 的潜力.
- 研究它们与一氧化碳 (CO) 和N-甲基异化物 (CNMe) 等小分子的结合相互作用.
主要方法:
- 密度函数理论 (DFT) 计算使用 ωB97XD ()/6-311+G* 理论水平.
- 对反应自由能和激活障碍的分析.
- 结合激活过程的机械研究.
- 能量分解分析 (EDA) 与化学价值的自然轨道 (NOCV) 用于研究结合相互作用.
主要成果:
- 计算的能量和障碍表明,碳稳定型玻利烯可以激活强大的E-H键.
- 这些玻利烯显示出与CO和CNMe结合的能力.
- 机理学研究显示,由于非无辜的碳化合物部分,合作债券分裂.
- EDA-NOCV分析显示了显著的相互作用能量,证实了CO和CNMe的强度结合.
结论:
- 碳稳定玻利具有激活强大的化学键的巨大潜力.
- 这些玻利烯可以有效地与CO和CNMe等小分子协调.
- 碳联体的合作作用提高了它们在键激活过程中的反应性.
相关概念视频
Regioselectivity and Stereochemistry of Hydroboration
8.2K
A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
8.2K
Hydroboration-Oxidation of Alkenes
8.5K
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
8.5K
Cycloaddition Reactions: MO Requirements for Thermal Activation
3.6K
Thermal cycloadditions are reactions where the source of activation energy needed to initiate the reaction is provided in the form of heat. A typical example of a thermally-allowed cycloaddition is the Diels–Alder reaction, which is a [4 + 2] cycloaddition. In contrast, a [2 + 2] cycloaddition is thermally forbidden.
3.6K
Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
18.4K
Introduction
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
18.4K
Cycloaddition Reactions: MO Requirements for Photochemical Activation
2.1K
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
2.1K
Acidity of 1-Alkynes
9.9K
The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.
9.9K


