1. Contribution from the Institute of Organic Chemistry, National Academy of Sciences of the Ukraine, 5 Murmanskaya Street, 02094 Kiev, Ukraine, Div. I.3 and V.4, Federal Institute for Materials Research and Testing (BAM), Richard-Willstätter-Strasse 11, D-12489 Berlin, Germany, Institute of Organic Chemistry, University of Regensburg, D-93040 Regensburg, Germany