This is an early access version, the complete PDF, HTML, and XML versions will be available soon. Open AccessArticle by Gabriela A. Corrêa , Susana L. H. Rebelo * and Baltazar de Castro LAQV/REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal * Author to whom correspondence should be addressed.