1. Department of Chemistry, University of California, Berkeley, California 94720, United States, Université de Bordeaux, UPR 8641, Pessac F-33600, France, and CNRS, UPR 8641, Centre de Recherche Paul Pascal (CRPP), Equipe “Matériaux Moléculaires Magnétiques”, 115 avenue du Dr. Albert Schweitzer, 33600 Pessac, France