Angewandte Chemie International Edition
Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Cover Picture: 5-Dehydro-1,3-quinodimethane: A Hydrocarbon with an Open-Shell Doublet Ground State (Angew. Chem. Int. Ed. 6/2004)
Contrary to the accepted guidelines for the occupancy of orbitals (such as Hund's rule or the Aufbau principle), three unpaired electrons are coupled antiferromagnetically in the 5-dehydro-m-xylylene triradical. This first example of an organic molecule with an “open-shell” doublet ground state is described by P. G. Wenthold, A. I. Krylov, and co-workers on page 742 ff. The cover pictures shows the singly occupied orbitals in the triradical and highlights the correlation between theoretical and experimental results.