In plant and cyanobacterial photosynthesis, the oxidation of water is carried out near Photosystem II (PSII) by the oxygen-evolving complex (OEC), which is a Mn4Ca cluster with primarily carboxylate ligation. It has been shown that the Ca in the OEC can be replaced by strontium, barium, cadmium, lanthanides, or others, and the oxygen-evolving activity of these substituted species have been investigated. Our group recently prepared isostructural synthetic models of the OEC with Ca or Sr, supporting the known ability of Sr to substitute for Ca in the native OEC with retention of significant activity (~40%). In the present study, we have therefore extended this work to lanthanides and have synthesized two new series of Mn-Ln compounds using a comproportionation reaction under acidic conditions with a bulky carboxylate ligand and phenanthroline. The syntheses, structures and magnetic properties of the obtained complexes will be described.

HeteronuclearMn-Ln clusters: Synthetic models of the lanthanide-substituted oxygen-evolving center (OEC) in photosynthesis and single-molecule magnets

245th National Meeting (2013)

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