1. Section of Chemical Information Systems, University of Ulm, Albert-Einstein-Allee 47, 89081 Ulm, Germany
2. Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
3. Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, Paseo de Belén, 7, 47011 Valladolid, Spain