Metalloenzymes are Nature's catalysts and are able to carry out remarkably difficult chemical transformations which often pose significant challenges in a laboratory setting (including the need for high temperatures, high pressures, and complex synthetic procedures). These enzymatic catalysts include nitrogenase (which converts dinitrogen to ammonia), the oxygen-evolving complex in photosystem II, and methane monooxygenase (which converts methane to methanol). In all these examples, a metal-based active site is the center of catalytic activity; and it is these transition metal active sites which have provided much inspiration for biomimetic model chemistry and for homogeneous catalysis, and are the focus of our research program.

We are interested in development and application of X-ray based spectroscopies as probes of electronic structure in biological and chemical catalysis. We study both enzyme systems and small molecule model complexes, which aim to mimic the enzyme activity. In particular, we are interested in the development of new spectroscopic methods which enable the characterization of intermediates in reaction cycles and hence may provide experimental insight into mechanisms. Our primary efforts focus on X-ray absorption and X-ray emission spectroscopic studies, which will be carried out at the Cornell High Energy Synchrotron Source (CHESS), the Stanford Synchrotron Radiation Laboratory (SSRL) and other synchrotron facilities. These data will be complemented by more traditional spectroscopy (UV-Vis, EPR and vibrational data), as well as modern electronic structure calculations. Our research program provides students with training in advanced spectroscopic methods, data analysis, theoretical calculations and basic synthesis, as well as the opportunity to collaborate with experts in biochemistry, synthetic chemistry and theory.

“X-ray Spectroscopic Observation of an Interstitial Carbide in NifEN-bound FeMoco Precursor” K. M. Lancaster, Y. Hu, U. Bergmann, M. W. Ribbe, S. DeBeer, J. Am. Chem. Soc. 2013, 135, 610-612
"Manganese K-Edge X-Ray Absorption Spectroscopy as a Probe of the Metal-Ligand Interactions in Coordination Compounds", M. Roemelt, M. A. Beckwith, C. Duboc, M.- N. Collomb, F. Neese, S. DeBeer, Inorg. Chem., 2012, 51, 680-687.

"X-ray Emission Spectroscopy Evidences a Central Carbon in the Nitrogenase Iron-Molybdenum Cofactor", K. M. Lancaster, M. Roemelt, P. Ettenhuber, Y. Hu, M. W. Ribbe, F. Neese, U. Bergmann, S. DeBeer, Science, 2011, 334, 974-977.

"Valence to Core X-ray Emission Spectroscopy: A Sensitive Probe of the Nature of a Bound Ligand" C. J. Pollock, S. DeBeer, J. Am. Chem. Soc., 2011, 133, 5594-5601.

“Identification of Light Atoms within Multinuclear Metal Clusters using Valence-to-Core X-Ray Emission Spectroscopy”, M. U. Delgado-Jaime, B. R. Dible, K. P. Chiang, W. W. Brennessel, P. L. Holland, U. Bergmann, S. DeBeer, Inorg. Chem.,  2011, 50, 10709-10717.

“Identification of Light Atoms within Multinuclear Metal Clusters using Valence-to-Core X-Ray
 Emission Spectroscopy”, M. U. Delgado-Jaime, B. R. Dible, K. P. Chiang, W. W. Brennessel, P. L. Holland, 
U. Bergmann, S. DeBeer, Inorg. Chem., 2011, 50, 10709-10717.

“Probing Valence Orbital Composition with Iron Kβ X-ray Emission Spectroscopy” N. Lee, T. Petrenko, U. Bergmann, F. Neese, S. DeBeer, J. Am. Chem. Soc., 2010, 132, 9715-9727.