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A Stable Aminyl Radical Coordinated to Cobalt
Rafael E Rodríguez-Lugo1,2,3, Bas de Bruin4, Monica Trincado1
1Department of Chemistry and Applied Biosciences, Eidgenössische Technische Hochschule Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|February 7, 2017
Summary
Researchers synthesized cobalt complexes with trop2NH and 2,2-bipyridine ligands. The study reveals the paramagnetic [Co(trop2N)(bpy)]+ complex exhibits a dominant cobalt(I)-aminyl radical character.
Area of Science:
- Organometallic Chemistry
- Coordination Chemistry
Background:
- Cobalt complexes are crucial in catalysis and materials science.
- Understanding ligand effects on metal center electronic structure is key.
Purpose of the Study:
- To synthesize and characterize novel cobalt complexes with trop2NH and 2,2-bipyridine ligands.
- To investigate the electronic structure and redox properties of these complexes, particularly the paramagnetic [Co(trop2N)(bpy)]+ species.
Main Methods:
- Synthesis and full characterization of cobalt complexes.
- Spectroscopic and structural analysis.
- Density Functional Theory (DFT) calculations.
- Reactivity studies, including hydrogen abstraction.
Main Results:
- Successful preparation and characterization of [Co(trop2N)(bpy)], [Co(trop2NH)(bpy)]+, and [Co(trop2N)(bpy)]+.
- Demonstration of interrelation via one-electron redox and proton transfer.
- Evidence for [Co(trop2N)(bpy)]+ existing as a mixture of cobalt(II)-amido and cobalt(I)-aminyl radical resonance structures.
- DFT calculations and reactivity data suggest a greater contribution of the cobalt(I)-aminyl radical form.
Conclusions:
- The study elucidates the electronic structure of a cobalt complex, highlighting the aminyl radical character.
- This work completes the series of Group 9 metal aminyl radical complexes with the trop2NH ligand.
- The findings contribute to the understanding of redox-active ligands and their influence on metal center properties.
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