Alexandra Nagelski

Dr. Sharon J. N. Burgmayer



Molybdenum pyranopterin dithiolene complex: Modeling the molybdenum cofactor


The molybdenum cofactor (Moco) forms the active site of all molybdenum enzymes and is vital for survival in all living organisms except saccharomyces cerevisiae, colloquially known as baker’s yeast. Moco also participates in the global nitrogen, carbon and sulfur cycles. This research focuses on the molybdopterin, which describes the one or two conserved pyranopterin dithiolene ligands on Moco and its role in the catalytic function of Moco. There is little known about the relationship between molybdopterin and the catalytic function of Moco, but without the molybdopterin, the cofactor loses its catalytic efficiency.

Additionally, this ligand is the most redox active ligand in all of biology and is energetically expensive to create, which makes it of significant focus in our research. To date, the Burgmayer lab group has created the model complex [TEA][Tp*Mo(X)pterin-C(CH3)2R-dithiolene], where TEA is tetraethylammonium, Tp* is tris(3,5-dimethylpyrazolyl)hydroborate, X is either oxygen or sulfur, Mo is either in the Mo(IV) or Mo(V) oxidation state, and R can be a hydroxyl, methyl or methoxy. The focus of my summer research is on the [Tp*Mo4+(O)S2MBMOPP]- system, which describes when R is a methoxy group and investigating the synthesis and isolation of this complex along with the changes on the catalytic efficiency and the electronics that it may exhibit.