关于碳基支持系统的促进光异构的理论理解
1Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, P. R. China.
概括
具有内部B-O键的化合物经历高效的光异构和结构变化. 这项研究揭示了激发和基本状态的反应机制,有助于设计先进的光响应材料.
科学领域:
- 有机金属化学 有机金属化学
- 摄影化学的使用.
- 计算化学计算化学
背景情况:
- 具有内部B-O键的化合物表现出独特的光异构化.
- 四坐标性有机系统在材料科学中至关重要.
- 了解激发状态动态是设计光响应材料的关键.
研究的目的:
- 研究碳基支四坐标系统的详细反应机制.
- 比较-氧 (B-O) 和- (B-N) 系统的反应性.
- 阐明影响有机化合物中光异构化的因素.
主要方法:
- 使用了多态完整活性空间自相一致场 (MS-CASSCF) 方法与二次扰动理论 (MS-CASPT2).
- 使用时间依赖密度函数理论 (TD-DFT) 进行理论计算.
- 通过使用 imine-substituted tetracoordinated organic boron系统 (BNMes2) 进行了比较研究.
主要成果:
- 在第一个激发单子 (S1) 和基 (S0) 状态中阐明了详细的反应机制.
- 确定了影响BOMes2和BNMes2光异构化活性的固体因素.
- 揭示了含系统的B-O和B-N之间的反应性差异.
结论:
- 这项研究合理化了对有机光异构的实验观测.
- 提供了对 heteroatom-doped tetracoordinate 机能化合物的兴奋状态动态的见解.
- 促进了基于的新型材料的合理设计,具有增强的光响应性.
相关概念视频
03:08Hydroboration-Oxidation of Alkenes
8.4K
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.
8.4K
02:36Regioselectivity 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
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
18.3K
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.
18.3K
02:15Preparation of Alcohols via Addition Reactions
6.3K
Overview
The acid-catalyzed addition of water to the double bond of alkenes is a large-scale industrial method used to synthesize low-molecular-weight alcohols. An acidic atmosphere is required to allow the hydrogen in the water molecule to act as an electrophile and attack the double bond in an alkene. The addition of a proton to the double bond creates a carbocation intermediate. The proton preferentially bonds to the less substituted end of the double bond to create a more stable carbocation...
The acid-catalyzed addition of water to the double bond of alkenes is a large-scale industrial method used to synthesize low-molecular-weight alcohols. An acidic atmosphere is required to allow the hydrogen in the water molecule to act as an electrophile and attack the double bond in an alkene. The addition of a proton to the double bond creates a carbocation intermediate. The proton preferentially bonds to the less substituted end of the double bond to create a more stable carbocation...
6.3K
01:12Cycloaddition 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
01:18Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism
2.2K
Birch reduction uses solvated electrons as reducing agents. The reaction converts benzene to 1,4-cyclohexadiene. The reaction proceeds by the transfer of a single electron to the ring to form a benzene radical anion. This anion is highly basic—it abstracts a proton from the alcohol to form a cyclohexadienyl radical. Another single electron transfer gives the cyclohexadienyl anion. A proton transfer from the alcohol forms 1,4-cyclohexadiene. Since this reduction occurs via radical anion...
2.2K