1. Department of Chemistry; University of Marburg; Hans-Meerwein-Straße 35032 Marburg Germany
2. Department of Chemistry; Faculty of Science; Al al-Bayt University; 25113 Mafraq Jordan
3. Department of NMR-based Structural Biology; Max-Planck-Institute for Biophysical Chemistry; Am Fassberg 11 37077 Göttingen Germany