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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >Preparation of a magnetic metal-organic square and metal-organic cubes using 4,5-bis(2-imidazolinyl)imidazolate: slow magnetization relaxation behavior in mixed-valent octamanganese(II/III) clusters
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Preparation of a magnetic metal-organic square and metal-organic cubes using 4,5-bis(2-imidazolinyl)imidazolate: slow magnetization relaxation behavior in mixed-valent octamanganese(II/III) clusters

机译：使用4,5-双（2-咪唑啉基）咪唑酸盐的制备磁性金属 - 有机正方形和金属 - 有机立方体：混合价八兰甘糖（II / III）集群中的缓慢磁化松弛行为

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Functional metal-organic squares (MOSs) and metal-organic cubes (MOCs) are important building units for zeolite-like metal-organic frameworks (ZMOFs), which are required to exhibit solid-state properties, such as dielectric, conductive, and magnetic properties. This work describes the preparation and magnetism of a tetracopper(ii) macrocyclic complex [Cu-4(II)(im-H(2)bizn)(4)(DMSO)(3)(THF)](ClO4)(4)center dot 8DMSO (1) (Him-H(2)bizn = 4,5-bis(4,5-dihydro-1H-imidazol-2-yl)imidazole) as a MOS and octametallic clusters [Ni-8(II)(im-H(2)bizn)(12)](ClO4)(4)center dot 10MeOH center dot 3H(2)O (2) and [(Mn4Mn4III)-Mn-II(im-H(2)bizn)(12)](ClO4)(8)center dot 14MeOH (3) as MOCs. The Cu-II ion in 1 possesses a five-coordinated square pyramidal geometry, resulting in the formation of an M4L4-type square, which gives an estimated intramolecular antiferromagnetic interaction with an exchange coupling constant of J(Cu-Cu) = -95 K. Meanwhile, 2 and 3 present six-coordinated octahedral geometries, giving M8L12-type cubes, of which 2 is a normal paramagnetic compound with intramolecular antiferromagnetic interactions, and where J(Ni-Ni) = -32 K. The most notable compound 3 is a (Mn4Mn4III)-Mn-II mixed valence state compound, which exhibits a slow magnetization relaxation behavior similar to that of single-molecule magnets. This is attributed to the contribution of magnetic anisotropy caused by the Jahn-Teller effect of the Mn-III ions. Utilizing a modified Arrhenius plot to extract the values of the thermal barrier for magnetization reversal (E-a/k(B)) and the pre-exponential factor (tau(0)), the parameters for the relaxation behavior were estimated to be E-a/k(B) = 6.38 K and tau(0) = 3.87 x 10(-7) s. UV-vis spectroscopy and electrochemical measurements in solution were also carried out. Compound 3 will be expected to lead to a solid-state material in which the magnetic and dielectric properties of encapsulated small molecules cooperate with the slow magnetization relaxation properties of the MOC backbone.
机译：功能性金属有机正方形（MOS）和金属有机立方体（MOC）是沸石类金属有机框架（ZMOF）的重要构建单元，它们需要表现出固态特性，如介电、导电和磁性。这项工作描述了四铜（ii）大环配合物[Cu-4（ii）（im-H（2）bizn）（4）（DMSO）（3）（THF）]（ClO4）（4）中心点8DMSO（1）（Him-H（2）bizn=4,5-双（4,5-二氢-1H-咪唑-2-基）咪唑）的制备和磁性，作为MOS和八金属簇[Ni-8（ii）（im-H（2）bizn）（12）]（ClO4）（4）中心点10MeOH中心点3H（2）O（2）和[（Mn-ii）bizn-12）中心点）14MeOH（3）作为主运行中心。1中的Cu II离子具有五配位的方形金字塔几何结构，导致形成M4L4型方形，其给出了交换耦合常数J（Cu Cu）=-95 K的估计分子内反铁磁相互作用。同时，2和3呈现六配位的八面体几何结构，给出了M8L12型立方体，其中2是具有分子内反铁磁相互作用的正常顺磁性化合物，其中J（Ni-Ni）=-32 K。最值得注意的化合物3是（Mn4Mn4III）-Mn II混合价态化合物，其表现出与单分子磁体类似的缓慢磁化弛豫行为。这归因于Mn III离子的Jahn-Teller效应引起的磁各向异性的贡献。利用改进的Arrhenius图提取磁化反转热障（E-a/k（B））和指数前因子（tau（0））的值，估计弛豫行为的参数为E-a/k（B）=6.38 k和tau（0）=3.87 x 10（-7）s。还进行了溶液中的紫外可见光谱和电化学测量。化合物3有望成为一种固态材料，其中封装小分子的磁性和介电性质与MOC主链的慢磁化弛豫性质相配合。

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