Molecular species containing more than one metal ion offer the possibility of co-operative behavior between the metal centers, which may lead to new properties and reactivity. Nature utilizes such co-operative properties in enzymes that catalyze several different processes, but moreover oligonuclear metal complexes are of fundamental interest in the field of molecule-based magnets, with the most thoroughly investigated examples of single molecule magnets being oxo- and hydroxo-bridged polymetallic systems.
Picture of ferritin with models (Taft et al. Science 1993) for the iron uptake and storage.
For some years we have been studying systematic variation of the electronic properties by means of varying the spin system in order to establish magneto-structural relationships for heterometallic compounds or metal complexes with additional spin carrying organic units.
In our continuing research work we prepare new coordination compounds starting from well-known transition metal clusters as building blocks using new synthetic strategies. Heteropolynuclear complexes and compounds bearing redox-active ligands are obtained and studied in detail by X-ray crystallography, spectroscopic methods like Mössbauer and UV-Vis as well as magnetic susceptibility measurements.