1. Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK, Fax: +44‐1865‐285002
2. Cancer Research UK Growth Factor Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, OX3 9DS, UK
3. Universita degli Studi di Firenze, Laboratorio di Chimica Bioinorganica, Room 188, Via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy