Use of the dicarboxylate ligand m-phenylenedipropionate for the synthesis of new Mn/O clusters. Syntheiss, characterization and magnetic properties

摘要

The quest for new Mn clusters that display large spin ground states or that can serve as a synthetic model for the water oxidation center in PSII has been pursued by usig the dicarboxylate ligand m-phenylenedipropionate (mpdp~(2-)). Ligand substitution of the acetate groups by this ligand in preformed clusters yields the compounds [Mn_2O(mpdp)(bpy)_2(MeCN)(H_2O)](ClO_4)_2 (1) and [Mn_3O(mpdp)_3(py)_3](ClO_4) (2), both similar in structure and properties to their acetate analogs. In a different reaction, mpdp~(2-) has allowed access to [Mn_6O_7(mpdp)_3(bpy)_3](ClO_4) (3), anew structural type whose electronic structure has been explored by measurements of its DC susceptibility and data indicate that it possesses a S = 3 2 ground state.