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

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 (mpd p(2-)). Ligand substitution of the acetate groups by this ligand in preform ed clusters yields the compounds [Mn2O(mpdp)-(bpy)(2)(MeCN)(H2O)](ClO4)(2) (1) and [Mn3O(mpdp)(3)(py)(3)](ClO4) (2), both similar in structure and pro perties to their acetate analogs. In a different reaction, mpdp(2-) has all owed access to [Mn6O7(mpdp)(3)(bpy)(3)](ClO4) (3), a new structural type wh ose electronic structure has been explored by measurements of its DC suscep tibility and data indicate that it possesses a S = 3/2 ground slate. (C) 20 01 Elsevier Science Ltd. All rights reserved.