| 四吡唑取代的[Mn8Ce]簇合物的合成、晶体结构与磁构关系研究 |
| Synthesis, Crystal Structure and Magneto-Structural Correlation of a [Mn8Ce] Cluster Substituted by Four Pyrazoles |
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| 摘要: 向Mn（O2CCH3）2·4H2O、吡唑和醋酸的乙腈/甲醇溶液中加入（NH4）2Ce（NO3）6得到1个四吡唑取代的[Mn8Ce]混金属簇合物[Mn8O8Ce（O2CCH3）12（pyr）4]·2CH3OH（2·2CH3OH，pyr为吡唑配体），并对其进行单晶结构分析、红外、元素分析和磁性研究。单晶结构研究表明，该化合物属于单斜晶系，P21/c空间群，8个Mn原子形成1个不在同一平面的八元环，然后通过8个μ3-O2-与位于环中心的1个CeⅣ连接起来。磁性研究表明，化合物中Mn3+离子之间是弱的铁磁性作用，基态自旋值S=6，交流磁化率虚部仅显示较微弱的频率依赖现象。通过研究系列[Mn8Ce]簇合物的磁构关系发现，配合物中随着含孤立μ3-O2-的∠MnOMn键角的增大和随着含桥连羧基O的∠MnOMn键角的减小，Mn3+间的铁磁性耦合增强，并进而导致化合物基态自旋值S的增大。 |
| 关键词: 磁构关系 晶体结构 单分子磁体 磁性调控 Mn-Ce簇合物 |
| 基金项目: 国家自然科学基金（No.21201136）和武汉工程大学科学研究基金（No.10122012）资助项目。 |
| Abstract: One [Mn8Ce] mixed metal cluster, namely, [Mn8O8Ce(O2CCH3)12(pyr)4]·2CH3OH (2·2CH3OH, pyr=pyrozole) has been obtained by adding (NH4)2Ce(NO3)6 to the acetonitrile/methanol solution containing Mn(O2CCH3)2·4H2O, pyrozole and acetic acid. The complex was fully characterized by X-ray single crystal structural diffraction, IR, elemental analysis and magnetic investigation. The structural analysis indicates that the complex crystallized in the monoclinic system, P21/c space group, and the eight MnⅢ ions formed a nonplanar loop, which was further attached to the central CeⅣ ion via eight μ3-O2- ions. Magnetic studies indicate that, within the cluster, the magnetic coupling interactions between Mn3+ ions are weak ferromagnetic, with the ground state Sbeing 6. Moreover, there are only very weak frequency-dependent signals from ac magnetic susceptibility investigations. By analyzing magneto-structural correlation of a series of [Mn8Ce] complexes, we found that with the angles at monoatomically bridging O2- increasing and with the angle at monoatomically bridging carboxylate Odecreasing, the ferromagnetic interactions between Mn atoms will be strengthened, which further lead to larger S. |
| Keywords: magneto-structural correlation crystal structure single molecule magnet, magnetic control Mn-Ce cluster |
| 投稿时间：2013-11-28 修订日期：2014-01-27 |
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| 王会生,潘志权.四吡唑取代的[Mn8Ce]簇合物的合成、晶体结构与磁构关系研究[J].无机化学学报,2014,30(5):1104-1110. |
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