Synthesis, structure and magnetic properties of Mn-12 single molecule magnet containing 4-(methylthio)benzoate as peripheral ligands

Abstract

[Mn12O12(O2CPh-4-SMe)(16)(H2O)4](.)7CH(2)Cl(2)(1), a new single-molecule magnet complex has been successfully synthesized by substitution of acetate ligand of Mn12ac with 4-(methylthio)benzoic acid. Complex 1 crystallizes into triclinic P (1) over bar with a = 18.321(3) angstrom, b = 19.011(3) angstrom, c = 27.230(4) angstrom, alpha = 86.973(3)degrees, beta = 76.919(3)degrees, gamma = 87.613(3)degrees, and Z = 2. In complex 1, one Mn(III) ion has an abnormal Jahn-Teller elongation axis oriented at an oxide ion. Complex 1 has two out-of-phase ac susceptibility peaks in the 2-4 K and 4-7 K regions. Effective anisotropy energy barrier and pre-exponential factor are U-eff = 45.95 K, 1/tau(0) = 8.6 x 10(9) s(-1) for chi(M)" peaks in the lower temperature region and U-eff = 59.45 K, 1/tau(0)= 2.2 x 10(8) s(-1) for chi(M)" peaks in the higher temperature region. The parameters of S = 10, g = 1.87, D = -0.40 cm(-1), and E = 0.00034 cm(-1) were obtained from the M/N mu(B) vs. H/T plot of complex 1.