从硫化量子点通过序列性质子合的单电子转移将转化为氨酸的光催化转化
Stephen C Jensen1, Stephanie Bettis Homan1, Emily A Weiss1
1Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
Journal of the American Chemical Society
|January 20, 2016
概括
硫化量子点使用可见光有效地将酸转化为氨酸. 酸性条件防止催化剂中毒,长时间保持高活性.
科学领域:
- 光催化
- 量子点
- 有机合成
背景情况:
- 可见光光催化为化学转化提供了可持续的途径.
- 硫化量子点 (CdS QD) 是一个有前途的半导体光催化剂.
- 在化学合成中,有效地将酸芳降解为素至关重要.
研究的目的:
- 调查CdS QD用于可见光驱动的酸降解为氨酸.
- 阐明光诱导的电子转移机制.
- 为持续的催化剂活性和产量优化反应条件.
主要方法:
- 用CdS QDs在3-mercaptopropionic酸的存在下对酸进行可见光照射.
- 暂时吸收光谱检测QD激子动态和电子转移.
- 核磁共振 (NMR) 光谱分析QD分子相互作用和产品吸附.
主要成果:
- 在54小时内达到37.1%的内部量子产量.
- 在纳米秒时间尺度上确定了3 - 墨烯酸 (∼5 ps) 的快速扫孔和随后的电子转移.
- 通过促进吸附和促进质子转移,证明酸性pH (3.6-4.3) 可以防止素中毒.
结论:
- CdS QD 是有效的可见光光催化剂,用于降低酸.
- 反应机制涉及连续的质子合电子转移,电子转移可能会限制速度.
- 优化pH值对于催化剂的稳定性和有效的酸转化至关重要.
相关概念视频
Electrophilic Aromatic Substitution: Nitration of Benzene
9.6K
The nitration of benzene is an example of an electrophilic aromatic substitution reaction. It involves the formation of a very powerful electrophile, the nitronium ion, which is linear in shape. The reaction occurs through the interaction of two strong acids, sulfuric and nitric acid.
9.6K
Photochemical Electrocyclic Reactions: Stereochemistry
2.4K
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
2.4K
Reduction of Benzene to Cyclohexane: Catalytic Hydrogenation
6.4K
Unlike the easy catalytic hydrogenation of an alkene double bond, hydrogenation of a benzene double bond under similar reaction conditions does not take place easily. For example, in the reduction of stilbene, the benzene ring remains unaffected while the alkene bond gets reduced. Hydrogenation of an alkene double bond is exothermic and a favorable process. In contrast, to hydrogenate the first unsaturated bond of benzene, an energy input is needed; that is, the process is endothermic. This is...
6.4K
Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism
2.8K
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...
2.8K
Electrophilic Aromatic Substitution: Sulfonation of Benzene
9.1K
Sulfonation of benzene is a reaction wherein benzene is treated with fuming sulfuric acid at room temperature to produce benzenesulfonic acid. Fuming sulfuric acid is a mixture of sulfur trioxide and concentrated sulfuric acid.
9.1K
meta-Directing Deactivators: –NO2, –CN, –CHO, –⁠CO2R, –COR, –CO2H
7.0K
All meta-directing substituents are deactivating groups. These substituents withdraw electrons from the aromatic ring, making the ring less reactive toward electrophilic substitution. For example, the nitration of nitrobenzene is 100,000 times slower than that of benzene because of the deactivating effect of the nitro group. The first step in an electrophilic aromatic substitution is the addition of an electrophile to form a resonance-stabilized carbocation. The energy diagrams for...
7.0K


![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)