1. Contribution from the Department of Chemistry, University of Gdańsk, Sobieskiego 18, 80-952 Gdańsk, Poland, Chemical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, Department of Chemistry, School of Engineering and Physical Sciencs, Heriot-Watt University, Edinburgh EH14 4AS, U.K., and Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218