Related Experiment Video
Updated: May 12, 2025
10:34
Exploring the Radical Nature of a Carbon Surface by Electron Paramagnetic Resonance and a Calibrated Gas Flow
Published on: April 24, 2014
10.7K
Exploring frustrated radical pairs through the persistent radical effect: methods of generation and recent
Darshika Singh1, Robert E Maleczka1
1Department of Chemistry, Michigan State University, 578 S. Shaw Ln, East Lansing, Michigan 48824-1322, USA. maleczka@chemistry.msu.edu.
Chemical Communications (Cambridge, England)
|April 28, 2025
Summary
Frustrated radical pairs (FRPs) are unique chemical entities that do not react with each other, enabling novel transformations. This review explores their generation and working principles, highlighting their potential in chemistry.
Area of Science:
- Organic Chemistry
- Physical Chemistry
Background:
- Radicals are fundamental to chemistry, with ongoing interest in their structure and reactivity.
- Frustrated radical pairs (FRPs) represent a novel class of radicals exhibiting unique behaviors.
- FRPs include both neutral and ionic types, characterized by non-reacting radical or radical ion pairs.
Purpose of the Study:
- To review the recent discovery and development of frustrated radical pairs (FRPs).
- To explore the generation methods and working principles of FRPs.
- To highlight the novelty and potential applications of FRPs in chemical transformations.
Main Methods:
- Review of recent literature on frustrated radical pairs.
- Analysis of examples showcasing FRP generation and reactivity.
- Discussion of the persistent radical effect facilitated by FRPs.
Main Results:
- FRPs exhibit orthogonal reactivities due to their non-reacting nature.
- The persistent radical effect enables challenging chemical transformations.
- Various methods for generating neutral and ionic FRPs have been identified.
Conclusions:
- Frustrated radical pairs offer a new paradigm in radical chemistry.
- Their unique reactivity opens avenues for novel synthetic strategies.
- FRPs hold significant potential for advancing chemical synthesis and understanding.
![[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)
Related Concept Videos
01:11Radical Reactivity: Overview
2.0K
Radicals, the highly reactive species, gain stability by undergoing three different reactions. The first reaction involves a radical-radical coupling, in which a radical combines with another radical, forming a spin‐paired molecule. The second reaction is between a radical and a spin‐paired molecule, generating a new radical and a new spin‐paired molecule. The third reaction is radical decomposition in a unimolecular reaction, forming a new radical and a spin‐paired...
2.0K
01:03Radical Formation: Overview
2.0K
A bond can be broken either by heterolytic bond cleavage to form ions or homolytic bond cleavage to yield radicals. A fishhook arrow is used to represent the motion of a single electron in homolytic bond cleavage. There are two main sources from which radicals can be formed:
Radicals from spin-paired molecules:
Radicals can be obtained from spin-paired molecules either by homolysis or electron transfer. While two radicals are formed in the former, an electron is added in the...
Radicals from spin-paired molecules:
Radicals can be obtained from spin-paired molecules either by homolysis or electron transfer. While two radicals are formed in the former, an electron is added in the...
2.0K
00:47Radical Formation: Addition
1.6K
Radicals can be formed by adding a radical to a spin-paired molecule. This is typically observed with unsaturated species, where the addition of a radical across the π bond leads to the production of a new radical by dissolving the π bond. For example, the addition of a Br radical to an alkene yields a carbon-centered radical.
Similar to charge conservation in chemical reactions, spin conservation is implicit for radical reactions. Accordingly, the product formed must possess an...
Similar to charge conservation in chemical reactions, spin conservation is implicit for radical reactions. Accordingly, the product formed must possess an...
1.6K
01:10Radical Reactivity: Steric Effects
1.9K
The presence of electron-donating, electron-withdrawing, or conjugating groups adjacent to a radical center, imparts electronic stabilization to the radicals. Examples of such electronically-stabilized radicals are triphenylmethyl, tetramethylpiperidine‐N‐oxide, and 2,2‐diphenyl‐1‐picrylhydrazyl. These radicals are remarkably stable and are known as persistent radicals. Some of the persistent radicals can even be isolated and purified.
Along with electronic...
Along with electronic...
1.9K
00:47Radical Formation: Abstraction
3.3K
The electron of an atom can be abstracted from a compound by a relatively unstable radical to generate a new radical of relatively greater stability. For example, an initiator which forms radicals by homolysis can abstract a suitable species like a hydrogen atom or a halogen atom from a compound to generate a new radical. This ability of radicals to propagate by abstraction is a crucial feature of radical chain reactions.
Even though homolysis produces radicals, it is different from radical...
Even though homolysis produces radicals, it is different from radical...
3.3K
00:51Radical Formation: Elimination
1.6K
Another method of radical formation is the elimination process. It is the opposite of the addition route and is driven by the instability of the radical. For example, as depicted in Figure 1, dibenzoyl peroxide yields a pair of unstable radicals upon homolysis. Given its instability, this radical spontaneously undergoes elimination via a C–C bond cleavage to form a relatively more stable phenyl radical. The mechanism involves cleavage of the bond between the α and β positions...
1.6K