This starter grant award to Princeton University supports the research of Professor Sonny C. Lee. The research focuses on an improved understanding of the structural chemistry of the iron-molybdenum cofactor in nitrogenase enzymes through investigation of metal-sulfur cluster core rearrangements. Certain reactions are known to transform common iron-sulfur geometries into clusters bearing structural affinities to the cofactor. This chemistry is applied to new clusters classes to construct higher nuclearity clusters with structural features similar to the iron-molybdenum cofactor. Clusters which are geometric isomers of the cofactor are specific targets, with the goal of attaining clusters with substantial topological homology to the cofactor. The research advances understanding of the fundamental structural chemistry of iron-sulfur clusters, leading to progress toward a chemical understanding of nitrogenase. The nitrogenase enzymes catalyze the reduction of atmospheric dinitrogen to ammonia, a reaction critical to the biological availability of fixed nitrogen.
