Mn_(12)-Ac磁性分子团簇单晶的热重-差热分析与结构转变  

Thermal analysis and structure transformation of Mn_(12)-Ac magnetic molecular crystals

作　　者：刘颖[1] 葛培文[1] 苏少奎[1] 张丽娟[2] 王云平[1] 

机构地区：[1]中国科学院物理研究所,北京100080 [2]北京化工大学理学院,北京100029

出　　处：《物理学报》2004年第11期4015-4020,共6页Acta Physica Sinica

基　　金：国家自然科学基金重点项目 (批准号 :10 3 3 40 80 );中国科学院知识创新工程重要方向性项目 (批准号 :KJCX2 SW W0 5 4)资助的课题~~

摘　　要：通过热重 差热分析 (TG DTA) ,考察了Mn1 2 Ac磁性分子晶体从室温到 2 70℃的热失重过程 .结合x射线粉末衍射分析 ,认为在第一个失重阶段 ,即 2 5— 110℃ ,Mn1 2 Ac失去了处于团簇分子间隙的结晶乙酸和结晶水 ,同时失去了团簇分子中与 4个Mn3+ 配位的 4个H2 O ,Mn1 2 Ac单晶结构被破坏 ,但是团簇分子的基本结构依然存在 ;在第二个失重阶段 ,即 180— 2 30℃ ,Mn1 2 Ac转变为γ Mn2 O3,其中混有少量Mn3O4 .The thermal stability of Mn 12-Ac [Mn 12(CH-3COO) 16(H-2O)-4O 12]52CH-3COOH54H-2O magnetic molecular crystals was investigated by TG-DTA from room temperature to 270℃. According to the results of XRD and TG, we found that Mn 12-Ac lost the crystal water and the acetic acid molecules of solvation which were located between the adjacent molecules in the temperature range from 25℃ to 110℃. At the same time, 4 H 2O which were linked with 4 Mn 3+ were lost. The crystalline structure of Mn 12-Ac single crystal was destroyed during this course. However, the core structure in the molecule was well preserved. From 180℃ to 230℃, a further transformation took place, Mn 12-Ac lost all the CH 3COO - ions and turned into γ-Mn 2O 3, with a little amount of Mn 3O 4.

关 键 词：分子团簇 磁性 配位 单晶结构 TG-DTA 分子间 分子晶体 热重-差热分析 热失重 乙酸 

分 类 号：O482.5[理学—固体物理]