[1] Univ Versailles St Quentin, Inst Lavoisier Versailles, UMR 8180, F-78035 Versailles, France
[2] Univ Paris 11, Equipe Chim Inorgan, Inst Chim Mol & Met Orsay, UMR 8182, F-91405 Orsay, France
[3] Univ Strasbourg, CNRS, IPCMS, UMR 7504, F-67070 Strasbourg, France
[4] Univ Grenoble 1, Grenoble 9, France
[5] CNRS, Inst Neel, Grenoble 9, France