1. a Department of Bioorganic Chemistry , Institute of Chemistry, Estonian Academy of Sciences , Tallinn , EE0026 , Estonia
2. b Université de Perpignan, Laboratoire de Chimie-Physique: ‘Quantitative Microfluorometry and Cellular Pharmacology’ , 66860 , Perpignan Cedex , France
3. c Institute of Chemical Physics and Biophysics, Estonian Academy of Sciences , Tallinn , EE0001 , Estonia