1. Department of Chemistry, Clemson University, Clemson, South Carolina 29634, Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Orgánica, E-28049 Madrid, Spain, Laboratory of Bioinorganic Chemistry, Faculty of Chemistry, University of Havana, Havana 10400, Cuba, and Institut Català d'Investigació Química (ICIQ), 43007 Tarragona, Spain