Single-Molecule Magnet Behavior in Heterometallic MII-MnIII2-MII Tetramers (MII = Cu, Ni) Containing MnIII Salen-Type Dinuclear Core
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- 作者：Chihiro Kachi-Terajima ; Hitoshi Miyasaka ; Ayumi Saitoh ; Naoki Shirakawa ; Masahiro Yamashita ; Rodolphe Clé ; rac
- 刊名：Inorganic Chemistry
- 出版年：2007
- 出版时间：July 23, 2007
- 年：2007
- 卷：46
- 期：15
- 页码：5861 - 5872
- 全文大小：668K
- 年卷期：v.46,no.15(July 23, 2007)
- ISSN：1520-510X
文摘
The linear-type heterometallic tetramers, [MnIII2(5-MeOsaltmen)2MII2(L)2](CF3SO3)2·2H2O (MII = Cu, 1a; Ni, 2a),where 5-MeOsaltmen2- = N,N'-(1,1,2,2-tetramethylethylene) bis(5-methoxysalicylideneiminate), and H2L = 3-{2-[(2-hydroxy-benzylidene)-amino]-2-methyl-propylimino}-butan-2-one oxime, have been synthesized and characterizedfrom structural and magnetic points of view. These two compounds are isostructural and crystallize in the samemonoclinic P21/n space group. The structure has a [MII-NO-MnIII-(O)2-MnIII-ON-MII] skeleton, where -NO- is alinking oximato group derived from the non-symmetrical Schiff-base complex [MII(L)] and -(O)2- is a biphenolatobridge in the out-of-plane [Mn2(5-MeOsaltmen)2]2+ dimer. The solvent-free compounds, 1b and 2b, have also beenprepared by drying of the parent compounds, 1a and 2a, respectively, at 100 
C under dried nitrogen. After thistreatment, the crystallinity is preserved, and 1b and 2b crystallize in a monoclinic P21/c space group without significantchanges in their structures in comparison to 1a and 2a. Magnetic measurements on 1a and 1b revealedantiferromagnetic MnIII···CuII interactions via the oximato group and weak ferromagnetic MnIII···MnIII interactionsvia the biphenolato bridge leading to an ST = 3 ground state. On the other hand, the diamagnetic nature of thesquare planar NiII center generates an ST = 4 ground state for 2a and 2b. At low temperature, these solvated (a)and desolvated (b) compounds display single-molecule magnet behavior modulated by their spin ground state.
C under dried nitrogen. After thistreatment, the crystallinity is preserved, and 1b and 2b crystallize in a monoclinic P21/c space group without significantchanges in their structures in comparison to 1a and 2a. Magnetic measurements on 1a and 1b revealedantiferromagnetic MnIII···CuII interactions via the oximato group and weak ferromagnetic MnIII···MnIII interactionsvia the biphenolato bridge leading to an ST = 3 ground state. On the other hand, the diamagnetic nature of thesquare planar NiII center generates an ST = 4 ground state for 2a and 2b. At low temperature, these solvated (a)and desolvated (b) compounds display single-molecule magnet behavior modulated by their spin ground state.