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Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
Tricyclopropylamine and Its Radical Cation.
de Meijere A1, Chaplinski, Winsel
1Institut für Organische Chemie der Universität, Tammannstrasse 2, D-37077 Göttingen (Germany).
Angewandte Chemie (International Ed. in English)
|August 24, 1999
Summary
Tricyclopropylamine exhibits a high ionization energy and oxidation potential due to its unique molecular geometry. Gamma irradiation reveals a significant structural transformation to a planar radical cation, as confirmed by EPR spectroscopy and computations.
Area of Science:
- Physical Chemistry
- Computational Chemistry
- Spectroscopy
Background:
- Tricyclopropylamine (1) displays distinct electronic properties compared to triisopropylamine.
- The molecular geometry of tricyclopropylamine, particularly the orientation of cyclopropyl groups around the nitrogen atom, is proposed to influence its properties.
Purpose of the Study:
- To investigate the unusual electronic properties of tricyclopropylamine.
- To elucidate the structural and conformational changes upon ionization.
- To correlate molecular structure with observed electronic and spectroscopic data.
Main Methods:
- Experimental determination of ionization energy and oxidation potential.
- Gamma irradiation of tricyclopropylamine to generate radical cations.
- Electron Paramagnetic Resonance (EPR) spectroscopy for radical cation characterization.
- Computational chemistry methods for structural and electronic analysis.
Main Results:
- Tricyclopropylamine shows a high first vertical ionization energy (8.44 eV) and oxidation potential.
- Gamma irradiation produces the tricyclopropylamine radical cation (1(.)(+)).
- EPR spectroscopy and computations reveal a planar, C(3h)-symmetrical structure for the radical cation.
- A dramatic conformational change occurs from the neutral molecule to the radical cation.
Conclusions:
- The unique geometry of tricyclopropylamine, with near-tetrahedral nitrogen and perpendicular cyclopropyl groups, explains its high ionization energy and oxidation potential.
- Ionization induces a significant structural rearrangement to a planar radical cation.
- The study highlights a previously unreported conformational change driven by electronic structure modifications.
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