Slow Magnetic Relaxation of a Ferromagnetic NiII5 Cluster with an S = 5 Ground State

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• 作者：Athanassios K. Boudalis ; Michael Pissas ; Catherine P. Raptopoulou ; Vassilis Psycharis ; Belé ; n Abarca ; Rafael Ballesteros
• 刊名：Inorganic Chemistry
• 出版年：2008
• 出版时间：November 17, 2008
• 年：2008
• 卷：47
• 期：22
• 页码：10674-10681
• 全文大小：345K
• 年卷期：v.47,no.22(November 17, 2008)
• ISSN：1520-510X

文摘

Complex [Ni₅{pyCOpyC(O)(OMe)py}₂(O₂CMe)₄(N₃)₄(MeOH)₂]·2MeOH·2.6H₂O (1·2MeOH·2.6H₂O) was synthesized by the reaction of Ni(O₂CMe)₂·4H₂O with pyCOpyCOpy and NaN₃ in refluxing MeOH. It crystallizes in the monoclinic C2/c space group and consists of five Ni^II atoms in a helical arrangement. Direct current magnetic susceptibility studies reveal ferromagnetic interactions between the Ni^II (S = 1) ions, stabilizing an S = 5 ground state. Alternating current susceptibility experiments revealed the existence of out-of-phase signals indicative of slow magnetic relaxation. Analysis of the signals showed that they are composite, suggesting more than one relaxation process, while analysis of their magnitudes suggests not all molecules undergo slow magnetic relaxation. Magnetization field-sweep experiments revealed hysteresis at 1.8 K, and magnetization decay experiments clearly verified the appearance of slow magnetic relaxation at that temperature.