1. Division of Pharmaceutical Chemistry, University of Helsinki, Viikinkaari 5 E, 00790 Helsinki (Finland), Fax: (+358) 9‐191‐59556
2. Department of Physical Sciences, University of Oulu, Linnanmaa, 90570 Oulu (Finland)
3. Department of Micro and Nanosciences, Helsinki University of Technology, Tietotie 3, 02150 Espoo (Finland)
4. Laboratory of Inorganic Chemistry, University of Helsinki, A. I. Virtasen aukio 1, 00560 Helsinki (Finland)