Redox-inactive metals are found in biological and heterogeneous water oxidation catalysts, but their roles are currently not well understood. Targeting synthetic model clusters of these catalysts, triphenylbenzene moieties appended with pyridine and alkoxide donors were employed as multinucleating ligands for first-row transition metals. Complexes of Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+ display trinuclear cores supported by bridging alkoxides. Trimanganese complexes were utilized as precursors to more elaborate metal oxide clusters. Tetranuclear complexes displaying Mn4, Mn3Ca and other Mn3M motifs (M = Na+, Sr2+, Zn2+, Sc3+, Y3+) with varied number of bridging oxo ligands were synthesized and studied. The reduction potentials of these clusters span a window of over 1 V. With the pKa of the redox-inactive metal-aqua complex as a measure of Lewis acidity, structurally analogous series of clusters display linear dependence between reduction potential and acidity. Implications for the function of oxygen evolving catalysts will be discussed.

Award Address  (ACS Award in Pure Chemistry sponsored by the Alpha Chi Sigma Fraternity and the Alpha Chi Sigma Educational Foundation). Heterometallic models of the oxygen evolving complex of photosystem II

245th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.