在双催化 PhotoATRPRP 中的素效应
Halil Ibrahim Coskun1, Rushik Radadiya1, Gorkem Yilmaz1
1Chemistry Department, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.
Macromolecules
|March 2, 2026
概括
基于的双催化光ATRP提供更快的聚合和较低的催化剂要求比基于的系统为甲基烯酸盐和甲基烯酸盐. 这项研究为优化控制激素聚合过程中的素和单体选择提供了关键的见解.
科学领域:
- 聚合物化学 聚合物化学
- 光催化作用的光催化
- 有机合成 有机合成
背景情况:
- 原子转移基聚合 (ATRP) 是一种强大的受控基聚合技术.
- 光诱导ATRP (photoATRP) 使用光来启动和控制聚合,提供时空控制.
- 双催化光ATRP将光催化与金属催化剂相结合,以提高控制和效率.
研究的目的:
- 研究类型 (与) 对甲基酸盐 (MA) 和甲基甲酸盐 (MMA) 双催化光ATRP的影响.
- 在绿色LED照射下,比较基于Br的系统与基于Cl的系统的效率,动力学和控制.
- 建立设计指南,以优化光ATRP中的素和单体选择.
主要方法:
- 在绿色LED灯下使用罗达6G (RD-6G) 作为光催化剂和CuX2 / 连接体复合物 (X = Br, Cl) 对光ATRP的系统研究.
- 对聚合率,激活和关闭过程的动态分析.
- 聚合物的合成有定义的链末端 (ω-和 ω-) 和分散的特征.
- 链延伸实验和时间控制研究,以评估链末忠实性和光介导调节.
主要成果:
- 与基于的系统相比,基于的系统表现出明显更快的激活和受控的聚合.
- 基于Br的系统需要较低的催化剂和光催化剂负载.
- MA的聚合速度比MMA更快,这归因于传播速率常数和失活剂减少速率.
- 最佳的配体选择 (MA的Me6TREN,MMA的TPMA) 对于控制聚合率和实现低分散度至关重要.
- 证实了高链端可靠性和高效的时间控制.
结论:
- 素类型在双催化光ATRP的性能中起着关键作用.
- 基于的系统在MA和MMA聚合的速度和催化剂效率方面提供了卓越的性能.
- 这些发现为根据特定的单体和期望结果量身定制光ATRP过程提供了有价值的设计原则.
![[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
相关概念视频
01:26Photochemical Electrocyclic Reactions: Stereochemistry
2.3K
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
2.3K
01:21Acid-Catalyzed α-Halogenation of Aldehydes and Ketones
5.0K
By replacing an α-hydrogen with a halogen, acid-catalyzed α-halogenation of aldehydes or ketones yields a monohalogenated product
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...
5.0K
02:46Halogenation of Alkenes
20.5K
Halogenation is the addition of chlorine or bromine across the double bond in an alkene to yield a vicinal dihalide. The reaction occurs in the presence of inert and non-nucleophilic solvents, such as methylene chloride, chloroform, or carbon tetrachloride.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
20.5K
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.9K
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
3.9K
01:12Cycloaddition Reactions: MO Requirements for Photochemical Activation
2.8K
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.
2.8K
00:51Base-Promoted α-Halogenation of Aldehydes and Ketones
4.3K
α-Halogenation of aldehydes and ketones is a reaction involving the substitution of α hydrogens with halogens in the presence of a base. The reaction begins with the abstraction of α hydrogen by the base to produce a nucleophilic enolate ion. This intermediate undergoes a subsequent nucleophilic substitution with the halogen to produce a monohalogenated carbonyl compound. If the starting substrate has more than one α hydrogen, it is difficult to stop the reaction...
4.3K