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Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium Under Mild Reaction Conditions
Published on: March 20, 2014
Intramolecular pi-dimerization in a 1,1'-bis(verdazyl)ferrocene diradical
Bryan D Koivisto1, Andrew S Ichimura, Robert McDonald
1Department of Chemistry, University of Victoria, P.O. Box 3065 STN CSC, Victoria, BC V8W 3V6, Canada.
Journal of the American Chemical Society
|January 19, 2006
Summary
This study presents the first pi-dimer of a stable verdazyl radical in the solid state. In solution, this structure is lost, and magnetic studies show the molecule is diamagnetic at room temperature due to strong antiferromagnetic coupling.
Area of Science:
- Organometallic Chemistry
- Radical Chemistry
- Crystallography
Background:
- Stable organic radicals offer unique electronic and magnetic properties.
- Verdazyl radicals are a well-known class of stable organic radicals.
- Ferrocene derivatives are widely studied for their electronic and structural versatility.
Purpose of the Study:
- To synthesize and characterize the solid-state structure of 1,1'-bis(verdazyl)ferrocene.
- To investigate the solution behavior and magnetic properties of this novel compound.
- To explore the formation of intramolecular pi-dimers involving stable verdazyl radicals.
Main Methods:
- Single-crystal X-ray diffraction to determine solid-state structure.
- Solution-state spectroscopic analysis (e.g., NMR, UV-Vis).
- Magnetic susceptibility measurements (e.g., SQUID magnetometry).
Main Results:
- The solid-state structure reveals an unprecedented intramolecular pi-dimer of two verdazyl radical moieties.
- The pi-dimer arrangement is not preserved in solution.
- Magnetic characterization demonstrates strong antiferromagnetic coupling between the radicals, leading to diamagnetism at room temperature.
Conclusions:
- 1,1'-bis(verdazyl)ferrocene represents the first example of a pi-dimer formed from stable verdazyl radicals in the solid state.
- The observed diamagnetism at room temperature highlights significant intramolecular radical-radical interaction.
- This finding opens new avenues for designing molecules with tunable magnetic properties based on radical-radical interactions.
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