Noble Metal Polyoxometalate Research
featured in Platinum Metals Review
Platinum Metals Rev., 2014, 58, (1), 40
General Research Interests
The research activity of the Kortz group is in the field of synthetic inorganic and organometallic chemistry. We are particularly interested in the preparation and structural characterization of large molecular assemblies called polyoxometalates. Polyoxometalates (or polyoxoanions) are metal-oxygen clusters with a tremendous structural variety and interesting properties in different fields including catalysis, medicine and materials science. The multitude of potential applications has led to significant interest in polyoxometalates worldwide. The first polyoxoanions were reported almost two centuries ago by Berzelius (1826), but they could only be characterized structurally more than 100 years later by Keggin (1933). Especially the availability of single-crystal X-ray diffraction has led to the discovery of a large number of novel polyoxoanions with different shapes and sizes.
The research activities of the Kortz group at Jacobs University Bremen are mainly focused on (a) hybrid organic-inorganic polyoxoanions and (b) transition metal-substituted polyoxoanions. The former class is of potential interest in medicine (virus and tumor inhibition, e.g. AIDS) and the latter in the areas of chemical and electrochemical catalysis (e.g. oxidation of organic substrates by O2) and materials science (e.g. sensor technology, single-molecule magnets). Polyoxoanions are synthesized and structurally characterized at Jacobs University Bremen using a multitude of solution and solid-state analytical techniques (e.g. NMR, XRD, IR, UV-Vis, AA). Investigation of the properties of our novel compounds is also accomplished in collaboration with expert colleagues from around the world (e.g. Prof. N. Dalal, Florida State University, USA and Prof. L. Nadjo, Université Paris-Sud, Orsay, France).
Research Interests in Nanomolecular Science
Polyoxometalates (or polyoxoanions) may be considered as intermediate between metal ions and extended metal-oxide lattices. In fact, polyanions are frequently referred to as ‘molecular metal-oxide fragments’. Some polyanion derivatives have the potential to become crucial building blocks of solid-state electronic, magnetic and optical devices in modern technology. Recent progress in polyoxometalate chemistry has allowed to design polyoxomolybdates and also polyoxotungstates with multiple functionalities and dimensions in the nano-regime via a bottom-up approach. Therefore this class of molecular compounds is predicted to play an important role in the rapidly expanding field of nanoscience and nanotechnology. Rational synthesis of polyoxometalates usually follows a self-assembly mechanism involving lacunary precursors. In the final product polyanion, these vacant subunits can incorporate functionalities that are appropriate for the construction of miniaturized molecular devices. The chemistry of nanomolecular polyoxoanions allows for molecular design of materials with interesting electronic and magnetic properties. Furthermore these species frequently exhibit unusual aspects of electron- and energy-transport. Recently, polyoxometalates have also been studied in colloid chemistry and in this context their stabilizing as well as catalytic role has been well established. New materials based on polyoxometalates and related colloidal particles are at a promising stage that can lead to the emergence of new technologies.