四吡唑取代的[Mn_8Ce]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 [Mn_8Ce] Cluster Substituted by Four Pyrazoles

作　　者：王会生[1] 潘志权[1] 

机构地区：[1]绿色化工过程教育部重点实验室,武汉工程大学化学与环境工程学院,武汉430074

出　　处：《无机化学学报》2014年第5期1104-1110,共7页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.21201136);武汉工程大学科学研究基金(No.10122012)资助项目

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。One [MnsCe] mixed metal cluster, namely, [Mn80 pyrozole） has been obtained by adding （NH4）2Ce（NO3）6 to 8Ce （O2CCH3）12 （pyr）4]. 2CH3OH （2.2CH3OH, pyr = the acetonitrile/methanol solution containing Mn （O2CCH3）2.4H20, 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 Ce rv ion via eight/J,3-O2- ions. Magnetic studies indicate that, within the cluster, the magnetic coupling interactions between Mn3＋ ions are weak ferromagnetic, with the ground state S being 6. Moreover, there are only very weak frequency-dependent signals from ac magnetic susceptibility investigations. By analyzing magneto-structural correlation of a series of [MnsCe] complexes, we found that with the angles at monoatomically bridging 02- increasing and with the angle at monoatomically bridging carboxylate O decreasing, the ferromagnetic interactions between Mn atoms will be strengthened, which further lead to larger S. CCDC： 963166.

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 

分 类 号：O614.711[理学—无机化学] O646.8[理学—化学]