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Magnetism of Self assemblies Consisting of Single-molecule Magnets

单分子磁体自组装体的磁性

基本信息

批准号：
17350070
负责人：
KOGA Noboru
金额：
$ 9.15万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

The studies aiming at the assemblization of single-molecule magnets (SMMs) based on the strategy of heterospin system have been proceeded. Dumbbell-type dinuclear single-molecular magnet was prepared by using the cobalt complex with tridentate pyridine ligand having dimethylamino groups at 2-and 6-position and dipyridildiazomethane (D1py_2). After irradiation, the complex showed slow magnetic relaxation characteristic to SMM in ac magnetic susceptibility measurements. However, the crystal amenable to X-ray crystal structure analysis could not be obtained. The cobalt complex obtained by mixing Co(p-tolsal)_2 and D1py_2 in 1:1 ratio, provide the SEM picture suggesting the formation of ID chains. In the dc magnetic susceptibilities measurement of the crystal sample after irradiation, the result indicating that the eight units of the cobalt ion and carbene interact ferromagnetically, was obtained. Furthermore, this cobalt complex showed a slow magnetic relaxation with U_<eff> = 87 K in ac magnetic susceptibility measurement and a hysteresis loop with H_c = 900 Oe in dc magnetic susceptibility measurement. These results indicate the formation of a ID chain. The complexes of Co(hfaci)_2, which is analogous to Co(hfac)_2, with D1py_2 and D2py_2 have a ID chain and a 2:2 cyclic structure, respectively, which were determined by X-ray structure analysis. They showed unique magnetic behaviors strongly affected by the interchain and intermolecular antiferromagntic interactions, respectively.

基于异旋体系的策略，对单分子磁体的组装进行了研究。以2位和6位二甲氨基吡啶配体和二吡啶二氮甲烷（D1py_2）为配合物，制备了哑铃型双核单分子磁铁。在交流磁化率测量中，辐照后的配合物对SMM表现出缓慢的磁弛豫特性。然而，无法获得适合x射线晶体结构分析的晶体。Co(p-tolsal)_2和D1py_2以1:1的比例混合得到的钴配合物提供了显示ID链形成的SEM图。在对辐照后晶体样品的直流磁化率测量中，得到了8个单位的钴离子与碳烯具有铁磁相互作用的结果。此外，该钴配合物在交流磁化率测量中表现为U_<eff> = 87 K的慢磁弛豫，在直流磁化率测量中表现为H_c = 900 Oe的磁滞回线。这些结果表明形成了一个ID链。与Co(hfac)_2类似的Co(hfaci)_2与D1py_2和D2py_2的配合物分别具有ID链和2:2的环状结构，这是通过x射线结构分析确定的。它们表现出独特的磁性行为，分别受到链间和分子间反铁磁相互作用的强烈影响。