Synthesis,Structure and Magnetic Properties of Mn_(12) Single Molecule Magnet Containing 4-(Methylthio)benzoate as Peripheral Ligands

摘要

[Mn_(12)O_(12)(O_2CPh-4-SMe)_(16)(H_2O)_4]centre dot7CH_2Cl_2 (1),anew single-molecule magnet complex has been successfully synthesized by substitution of acetate ligand of Mnl2ac with 4-(methylthio)benzoic acid.Complex 1 crystallizes into triclinic P1 with a=18.321(3) A,b=19.011(3) A,c=27.230(4) A,alpha=86.973(3)deg,beta=76.919(3)deg,gamma=87.613(3)deg,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~(II) peaks in the lower temperature region and U_(eff)=59.45 K,1/tau_0=2.2X10~8s~(-1) for CHI_M~(II) 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/Nmu_B vs.H/T plot of complex 1.