MIIIDyIII3 (M = FeIII, CoIII) Complexes: Three-Blade Propellers Exhibiting Slow Relaxation of Magnetization
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- 作者：Gong-Feng Xu ; Patrick Gamez ; Jinkui Tang ; Rodolphe Cl茅rac ; Yun-Nan Guo ; Yang Guo
- 刊名：Inorganic Chemistry
- 出版年：2012
- 出版时间：May 21, 2012
- 年：2012
- 卷：51
- 期：10
- 页码：5693-5698
- 全文大小：353K
- 年卷期：v.51,no.10(May 21, 2012)
- ISSN：1520-510X
文摘
[DyIII(HBpz3)2]2+ moieties (HBpz3鈥?/sup> = hydrotris(pyrazolyl)borate) and a 3d transition-metal ion (FeIII or CoIII) have been rationally assembled using an dithiooxalato dianion ligand into 3d-4f [MDy3(HBpz3)6(dto)3]路4CH3CN路2CH2Cl2 (M = Fe (1), Co (2) complexes. Single-crystal X-ray studies reveal that three eight-coordinated DyIII centers in a square antiprismatic coordination environment are connecting to a central octahedral trivalent Fe or Co ion forming a propeller-type complex. The dynamics of the magnetization in the two isostructural compounds, modulated by the nature of the central MIII metal ion, are remarkably different despite their analogous direct current (dc) magnetic properties. The slow relaxation of the magnetization observed for 2 mainly originates from isolated Dy ions, since a diamagnetic CoIII metal ion links the magnetic DyIII ions. In the case of 1, the magnetic interaction between S = 1/2 FeIII ion and the three DyIII magnetic centers, although weak, generates a complex energy spectrum of magnetic states with low-lying excited states that induce a smaller energy gap than for 2 and thus a faster relaxation of the magnetization.