[1] Univ Bordeaux 1, LCOO, UMR 5802, F-33405 Talence, France
[2] Inst Charles Sadron, CNRS, F-67083 Strasbourg, France
[3] Kekule Inst Organ Chem & Biochem, D-53121 Bonn, Germany
[4] Rudjer Boskovic Inst, Dept Chem & Biochem, Lab Supramol & Nucleoside Chem, Zagreb 10000, Croatia