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

Abstract 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 using the dicarboxylate ligand m -phenylenedipropionate (mpdp 2− ). Ligand substitution of the acetate groups by this ligand in preformed clusters yields the compounds [Mn 2 O(mpdp)(bpy) 2 (MeCN)(H 2 O)](ClO 4 ) 2 ( 1 ) and [Mn 3 O(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 6 O 7 (mpdp) 3 (bpy) 3 ](ClO 4 ) ( 3 ), a new 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.