Tuning reactivity of biologically inspired clusters via metal and bridging anion composition

Complex inorg. cofactors perform challenging catalytic transformations in biol. systems, such as photosystem II and nitrogenase. The effect of cluster structure on the phys. and chem. properties of these active sites is not well understood. We have developed methodologies for the rational synthesis of tetranuclear homo- and hetero-metallic clusters. The effect of metal compn. on redn. potentials has been correlated to Lewis acidity for redox inactive metals. Clusters with open coordination site have been prepd. for small mol. activation. CH and CF oxygenation has been obsd. for putative terminal Fe-oxo species supported by tetranuclear clusters. Tetranuclear clusters with bridging fluoride and oxide interstitial ligands have been synthesized. Activation of nitric oxide by these clusters as a function of the interstitial ligand and metal oxidn. state has been studied. Implications for the function of biol. catalysts will be discussed