1. University of Agricultural Sciences and Veterinary Medicine, Faculty of Biotechnologies, Department of Chemistry, B-dul Marasti nr. 59, 71331-Bucharest, Roumania, Università degli Studi di Firenze, Laboratorio di Chimica Bioinorganica, Rm. 188, Via della Lastruccia 3, I-50019 Sesto Fiorentino (Firenze), Italy, Institute of Virology, Slovak Academy of Sciences, Dubravska cesta 9, 842 45 Bratislava, Slovakia, and “C.D. Nenitzescu” Institute of Organic Chemistry, Splaiul Independentei 202B, Bucharest, Roumania