Field-induced CoⅡ single-ion magnet with pentagonal bipyramidal configuration
A mononuclear CoⅡ complex,[Co(H2dapsc)(H2O)Cl]Cl·2H2O(1),with a pentagonal bipyramidal configu-ration was obtained by reflux reaction of CoCl2·6H2O and 2,6-diacetylpyridine-bis(semicarbazone)(H2dapsc)in a mixed solvent of water and ethanol.The neutral ligand H2dapsc molecule provides five coordination atoms to form the equatorial plane of 1,while a water molecule and a Cl-ion occupy their axial positions.At the same time,the sol-id structure contains a valence counteranion Cl-ion and two lattice water molecules.The study of DC magnetic sus-ceptibility indicates that complex 1 has strong magnetic anisotropy.The AC magnetic properties show the existence of slow magnetic relaxation behavior,which is dominated by both direct and Raman processes.The energy barrier for magnetization reversal was 55.55 K.Based on theoretical calculations,it can be concluded that the main reason for the slow magnetic relaxation behavior is the rhombic anisotropy of the pentagonal bipyramidal structure.The cal-culated D and E values were 45.68 and-0.32 cm-1.
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