Synthesis and Structure of Two Dodecanuclear Manganese Clusters Based on Mixed Acids

Two new Mn12O12 cores based dodecanuclear manganese complexes formulated with [Mn12O12(O2CMe)(8) (O2CEt)(8)(H2O)(4)]center dot 2H(2)O (1) and [Mn12O12(O2CMe)(12)(O2CCl3)(4)(H2O)(4)]center dot 4MeCO(2)H center dot 8H(2)O (2) have been synthesized by the reaction of Mn(O2CMe)(2)center dot 4H(2)O, KMnO4 and mixed acid of RCO2H and MeCO2H (R=Et (1), Cl3CCO2H (2)) in acidic conditions. X-ray diffraction crystal structure analysis shows that the complex 1 crystallizes in the tetragonal space group I (4) over bar has a=b=2.650 5(3) nm, c=1.349 7(3) nm and Z=4. The complex 2 crystallizes in tetragonal space group I4(I)/acd has a=b=2.706 7(1) nm, c=2.588 0(2) nm and Z=8. In the two complexes, the structure of the Mn12O12 core is similar to that found in all classic Mn-12 derivatives and comprises a central Mn4O4 cubane core surrounded by a nonplanar Mn8O8 ring held together with mu(3)-oxo bridges, while the peripheric bridging is ensured by sixteen eta(2)-mu-mixed carboxylate anions in different orientations which provide an acidic condition. The effect of pKa data in each mixed acid system for obtaining the two complexes are also investigated in this article. CCDC: 847334, 1; 847335, 2.