The work reported here has been carried out at the Institute of Inorganic Chemistry, RWTH Aachen University under the supervision of Prof. Dr. Ulli Englert between December 2001 and March 2004. I would like to express my gratitude to the extraordinary Prof. Dr. Ulli Englert for giving me the great opportunity to work in his group, for the interesting subject of my research, for all the help, patience, guidance and support he offered me over the last years. His excellent teaching and supervising qualities contributed massively to my scientific career and prompt me to reach this point. I would like to thank Prof. Dr. Markus Albrecht for his kindly assumption of the coreference.weiterlesen