1. Contribution from the Department of Chemistry and Biochemistry and Institute for Cellular and Molecular Biology, 1 University Station - A5300, University of Texas at Austin, Austin, Texas 78712-0165, Department of Chemistry, M. V. Lomonosov Moscow State University, Leninskie Gory, 119899 Moscow, Russian Federation, and A. N. Nesmeyanov Institute of Organoelement Compounds, 28 Vavilova str., 117997 Moscow, Russian Federation