Abstract
Based on XRD and optimized structures of the cage compound [(V~2~O~3~)~2~(PhPO~3~)~4~⊂F]^–n^ in singlet (n = 1) and doublet (n = 2) states DFT calculations were carried out to determine the energies and spin density distribution for the symmetries D~2__d__~, C~2__v__~, and C~s~. It turned out, that the cage with C~s~ symmetry not only represents the energetically more stable doublet system (with respect to D~2__d__~ and C~2__v__~‐symmetries) but also corresponds to the real compound under study. The SOMO of the S = 1/2 cage represents an antibonding state and the volume of the cage in this state is larger than that in the S = 0 state. The calculated ESR hyperfine coupling constants are in acceptable agreement with those determined by ESR. Experimentally the localization/delocalization of spin density was determined via ESR as a function of temperature and adsorption of the cage on Al~2~O~3~, respectively. A proposal is given for the localization/delocalization of spin density based on thermally driven changes of the cage symmetry in combination with the hopping of the unpaired electron inside the cage.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)