1. a Centre for Theoretical and Computational Chemistry, Department of Chemistry , University of Oslo , P.O.B. 1033 Blindern, N-0315 Oslo , Norway
2. b Institute of Organic Chemistry, Polish Academy of Sciences , Kasprzaka 44, 01224 Warsaw , Poland
3. c Laboratory of NMR Spectroscopy, Department of Chemistry , University of Warsaw , Pasteura 1, 02-093 Warsaw , Poland