CHEMISTRY:
Odd Electron on Nitrogen: A Metal-Stabilized Aminyl Radical
Wolfgang Kaim
Nitrogen-centered radicals could play a role in biological systems, but no proof of such a role has been reported as yet. In his Perspective, Kaim discusses how these chemical species could be stabilized in a biological context. He highlights the report by Büttner et al., who have synthesized, isolated, and characterized an aminyl radical (NR2·) stabilized by metal coordination. Crystallographic data, quantum chemical calculations, and sophisticated electron paramagnetic resonance investigations confirm that the unpaired electron is located mainly on the nitrogen atom of the aminyl. The principle of radical stabilization and control by metal complexes has thus been extended from oxygen- and carbon-centered to nitrogen-centered radicals, suggesting that the latter species may also be discovered in biology.
The author is at the Institut für Anorganische Chemie, Universität Stuttgart, 70550 Stuttgart, Germany, and at the Department of Chemistry and Biochemistry, Northern Illinois University, De Kalb, IL 60115, USA. E-mail: kaim{at}iac.uni-stuttgart.de
