Related Experiment Video
Updated: Jul 3, 2026
08:22
Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
Molecular recognition in a heteromolecular radical pair system with complementary multipoint hydrogen-bonding
Hidenori Murata1, Paul M Lahti, Safo Aboaku
1Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA.
Chemical Communications (Cambridge, England)
|July 18, 2008
Summary
Stable radical complexes, Ur6IN and DAPPN, form unique heterospin pairs. Complementary hydrogen bonds drive the formation of these multi-point radical interactions.
Area of Science:
- Chemistry
- Materials Science
- Supramolecular Chemistry
Background:
- Stable organic radicals are key building blocks in molecular magnetism and spintronics.
- Designing radical complexes with controlled spin interactions is crucial for developing advanced materials.
Purpose of the Study:
- To synthesize and characterize novel heterospin radical pair complexes.
- To investigate the role of hydrogen bonding in the self-assembly of radical systems.
Main Methods:
- Synthesis of Ur6IN (2-(6-uradinyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-1-oxyl) and DAPPN (4-(p-tert-butylaminoxylphenyl)-2,6-di(propylamido)pyridine).
- Crystallographic analysis to determine the structure of the radical pair complexes.
- Spectroscopic methods to confirm the integrity and properties of the radicals within the complex.
Main Results:
- Successful formation of heterospin radical pair complexes involving Ur6IN and DAPPN.
- Evidence of complementary multi-point hydrogen-bonds mediating the complex formation.
- Structural characterization revealing specific arrangements facilitating spin interactions.
Conclusions:
- Complementary hydrogen bonding is an effective strategy for constructing well-defined heterospin radical pair complexes.
- The observed complex formation opens avenues for designing novel magnetic materials based on organic radicals.
Related Concept Videos
01:11Radical Reactivity: Overview
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 molecule. These three...
00:54Radical Formation: Homolysis
A bond is formed between two atoms by sharing two electrons. When this bond is broken by supplying sufficient energy, either two electrons can be taken up by one atom forming ions by the cleavage called heterolysis, or the two electrons are shared by two atoms, with one each creating radicals by the cleavage called homolysis.
01:03Radical Formation: Overview
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 latter, also known...
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 latter, also known...
00:47Radical Formation: Abstraction
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...
01:27π Molecular Orbitals of the Allyl Radical
Allyl radicals are three-carbon conjugated systems. They are readily formed as intermediates in halogenation reactions of alkenes involving the addition of halogen to the allylic carbon instead of the double bond. As seen in allyl cations and anions, each of the three sp2-hybridized carbon atoms in allyl radicals has an unhybridized p orbital. These orbitals combine to give three π molecular orbitals.
The allyl systems have identical molecular orbitals but differ in the number of π electrons.
The allyl systems have identical molecular orbitals but differ in the number of π electrons.
01:33Radical Reactivity: Intramolecular vs Intermolecular
Radical reactions can occur either intermolecularly or intramolecularly. In an intermolecular radical reaction, a nucleophilic radical adds to an electrophilic alkene or vice versa. In such reactions, the radical and generally the alkene, which is also called the radical trap, are two different molecules. Additionally, for such intermolecular reactions to occur, the radical trap must be active, present in an excess concentration, and the radical starting material must have a weak carbon–halogen...