1. Department of Chemistry, St. Petersburg State University, 198904 Stary Petergof, Russian Federation, Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal, and Dipartimento Farmaco-Chimico, University of Bari, via E. Orabona 4, I-70125 Bari, Italy