Influence of the ligands and solvents on the magnetic properties of the single molecule magnets: [Mn12O12(O2CR)16(L)4]·nS (R=3-ClC6H4, L=3-ClC6H4CO2H and water, n=1, S=3-ClC6H4CO2H (1); R=CH2Cl, L=water, n=0 (2))

The syntheses and magnetochemical properties of the title complexes are reported. The crystal structure of complex 1 has been characterized by X-ray diffraction. It is shown that the central core of complex 1 consists of a central cubane-like [MnIV 4O4]8+ held within a nonplanar ring of eight MnIII ions by eight μ3-O2− ions. The ligations of complex 1 are provided by 16 η2-μ-carboxylate groups and three water ligands as well as one terminal ligand 3-ClC6H4CO2H. For both complexes 1 and 2 the χ′′m signals are observed in the region 2–10 K, measured at frequencies of 133, 1333, 9333 Hz, and exhibit two frequency-dependent χ′′m peaks with a predominant peak in the 4–10 K region. The magnetization hysteresis loops for complexes 1 and 2 show a step-like character. These steps are attributable to resonant magnetization tunneling. Both the DC and AC susceptibility measurements indicate the difference in the ground-state spin S=9 and S=10 for complexes 1 and 2, respectively. The effects of ligands and solvents on the magnetic properties of the title complexes are briefly discussed.