Turning on Single-Molecule Magnet Behavior in a Linear {Mn3} Compound
Turning on Single-Molecule Magnet Behavior in a Linear {Mn3} Compound
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DOI：
10.1021/ic301820w
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发表时间：
2013-02-04
影响因子：
4.6
通讯作者：
Murugesu, Muralee
中科院分区：
文献类型：
--
作者：
Habib, Fatemah;Brunet, Gabriel;Murugesu, Muralee
报告了一种新型锰化合物的合成、结构和磁性能，该化合物具有以线性方式排列的混合价 {Mn-3} 核。先前报道的配合物 1，[Mn-3(IV)(dpo)(6)]中心点 2MeCN，其中 H(2)dpo 是 (E)-1-羟基-1,1-二苯基丙-2-酮肟，作为通过 Mn-(OAc)2 中心点 4H(2)O、H(3)oxol 反应分离具有类似核心排列的 {Mn-3} 化合物的起点。 (E)-2,5-二羟基-2,S-二甲基己-3-酮肟)和NaOH的MeOH和MeCN溶液。通过使用这些反应条件，成功分离出化合物 2，即 Na[(Mn2MnIII)-Mn-IV(Hoxol)(6)](n) 中心点 MeOH 中心点 H2O，揭示了中心 Mn-III 离子，从而向系统引入结构和磁各向异性。 2的结构揭示了线性三核Mn-IV-(MnIII-MnIV)单元通过Na+离子连接形成线性一维配位聚合物。每个三核单元的 Jahn-Teller 轴在同一链内平行排列，并在两个对称相关链之间形成 75 度角。在 1.9-300 K 温度范围内对 1 和 2 进行磁化率测量表明，只有还原化合物 2 是单分子磁体 (SMM)，这主要是由于 Mn-III 离子上的 Jahn-Teller 畸变引入的各向异性，有效地诱导了这种磁体行为。通过 Na+ 阳离子沿着链的弱反铁磁相互作用导致 Mn-IV-Mn-III-Mn-IV SMM 的固有特性的调节。
The synthesis, structure, and magnetic properties are reported for a new manganese compound with a mixed-valent {Mn-3} core arranged in a linear fashion. The previously reported complex 1, [Mn-3(IV)(dpo)(6)]center dot 2MeCN, where H(2)dpo is (E)-1-hydroxy-1,1-diphenylpropan-2-one oxime, served as a starting point for the isolation of a {Mn-3} compound with an analogous core arrangement through the reaction of Mn-(OAc)2 center dot 4H(2)O, H(3)oxol ( (E)-2,5-dihydroxy-2,S-dimethylhexan-3-one oxime), and NaOH in MeOH and MeCN. By using these reaction conditions, compound 2, Na[(Mn2MnIII)-Mn-IV(Hoxol)(6)](n)center dot MeOH center dot H2O, was successfully isolated revealing a central Mn-III ion thereby introducing structural and magnetic anisotropy to the system. The structure of 2 reveals linear trinuclear Mn-IV-(MnIII-MnIV) units connected through Na+ ions forming a linear one-dimensional coordination polymer. The Jahn-Teller axes of each trinuclear unit are aligned parallel within the same chain and form a 75 degrees angle between the two symmetry related chains. Magnetic susceptibility measurements of 1 and 2 in the temperature range 1.9-300 K reveal that only the reduced compound, 2, is a single-molecule magnet (SMM) largely due to the anisotropy introduced by the Jahn-Teller distortions on the Mn-III ions, which effectively induce this magnet behavior. Weak antiferromagnetic interactions along the chains through the Na+ cations lead to a modulation of the intrinsic properties of the Mn-IV-Mn-III-Mn-IV SMMs.