1. Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 842 36 Bratislava, Slovakia, Computational Center for Molecular Structure and Interactions, Department of Chemistry, Jackson State University, 1400 Lynch Street, P.O. Box 17910, Jackson, Mississippi 39217, Austrian Research Centers Seibersdorf, A-2444 Seibersdorf, Austria, and Institute for Theoretical Chemistry, University of Vienna, Währingerstrasse 17, A-1090, Austria