Bioinorganic Chemistry has developed in the last 30 years to become a field that attracts a broad spectrum of scientists that range from biochemists, enzymologists, coordination chemists, spectroscopists to theoreticians. The draw for these scientists is the unique role that transition metals play in biology. They act as catalysts in the transformation of biological molecules to mediate essential biological processes. The ultimate goal of bioinorganic chemistry is the determination of mechanisms of enzymatic reactions on a molecular level. Our research evaluates the properties of metal centers in enzymes using inorganic model complexes that we investigate with high-end spectroscopic methods to provide insight into how these metalloproteins work.

In comparison, Bioorganometallic Chemistry is a relatively new field that is focused on the properties of metal-carbon bonds in biology and their utilization for catalysis. The by far most prominent example for this area is coenzyme B12 (cobalamine), which corresponds to a cobalt complex of a highly functionalized porphyrin derivative (a 'corrin' macrocycle). More recent examples are nickel-hydrocarbyl complexes as observed in the methane generating enzyme Methyl-Coenzyme M Reductase (MCR), which again contains a porphyrin-derivative as ligand for the catalytically active metal ion (cofactor 'F430'). We are especially interested in hydrogenases, which are enzymes that catalyze the conversion of protons into dihydrogen (and vice versa). These enzymes are of special interest in the area of alternative energies.

For the investigation of the bioinorganic model complexes, a number of sophisticated spectroscopic methods are used. However, in order to apply them to the usually quite complicated vibrational or electronic spectra of metalloporphyrins, it is necessary to calibrate these methods using simple metalloporphyrin complexes. Therefore, we are carrying out high-level Spectroscopic Investigations of Metalloporhyrins using magnetic circular dichroism and polarized resonance Raman spectroscopy on a number of compounds of type [MIII(TPP)X] (M = Fe, Co, Mn; X = Cl, ClO4, SR, etc.; TPP = Tetraphenylporphyrin).

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