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Published on: August 2, 2012
Self-assembly of fish-bone and grid-like CoII-based single-molecule magnets using dihydrazone ligands with NNN and
Qianqian Yang1,2, Guo-Lu Wang3, Yi-Quan Zhang3
1State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China. tang@ciac.ac.cn.
Abstract:
Three CoII complexes, [Co2(H2L1)2](ClO4)4·4CH3OH (1), [Co2(H4L2)2](ClO4)4 (2) and [Co4(H4L2)4](ClO4)8 (3), were constructed by the self-assembly of the symmetrical dihydrazone ligands H2L1 and H4L2 with CoII ions under different synthetic conditions. The fish-bone-like complex 1 was obtained using the ligand H2L1 in methanol via the solvothermal method, while the self-assembly of H4L2 with CoII ions is solvent-dependent, producing the fish-bone-like complex 2 and [2 × 2] grid-like complex 3. Magnetic susceptibility measurements and theoretical calculations reveal that the large negative D values for the three complexes stem from their easy-axis magnetic anisotropy. Ac magnetic susceptibility measurements disclosed field-induced slow magnetic relaxation behaviors and the presence of Raman and/or direct processes of the three complexes at various applied dc fields.
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