SYNTHESIS OF NOVEL HIGH-SPIN METAL COMPLEXES AND THEIR MULTI-FUNCTIONALITY

新型高自旋金属配合物的合成及其多功能性

• 批准号: 11640591
• 负责人: KURODA-SOWA Takayoshi
• 金额: $ 2.3万
• 依托单位: KINKI UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640591/
• 关键词: SINGLE-MOLECULE MAGNET; Mn12 complex; MAGNETIZATION; CHARGE-TRANSFER COMPLEX; CARBOXYLIC ACID; TTF DERIVATIVES; CHARGE-TRANSFER BAND; 多核マンガン錯体; 巨大スピン; メスバウアー

The target of this project was the development of new single-molecule magnets based on Mn12 complexes.1) Chemical modification of Mn12 complexes.Mn12 complexes are known as single-molecule magnets with the highest blocking temperature. Their 16 bridging acetate groups can be replaced by other carboxylic acids. We have tried to replace the bridging acetate groups to decanoic acid, 1-adamantanecarboxylic acid, trans-3-(3-thienyl) acrylic acid, heptafluorobutanoic acid, dichloroacetic acid, and trichloroacetic acid. The ligand-exchange reactions were successful for most of ligands ; the resulting compounds retains the magnetic properties typical for single-molecule magnets. The blocking temperatures TB for them were all 2.8 K, which was a little lower than 3.0 K for the Mn12-acetate. However, the compound obtained by replacing acetate to decanoic acid showed antiferromagnetic behavior, indicating that this compound is not a single-molecule magnet.2) Formation of charge-transfer complexes of a Mn12 complex with various donor moleculesWe have tried the formation of charge-transfer complexes of a Mn12 complex with various TTF-type donor molecules. When we mixed solutions of dimethyldiphenyl-tetrathiafluvalene and Mn12-pentafluorobenzoate complex, one-electron transfer takes place to form the cationic TTF derivative and anionic Mn12 compound. By standing the methylenechloride solution with diffusion solvent for one week, reddish-black fine crystals were obtained. The solution UV-vis spectrum shows intense absorption band at around 520 nm with a molar absorption coefficient ε more than 30000, which can be attributed to the charge-transfer band between Mn12 anion and TTF-derivative cation. On the basis of solution esr, nmr and UV-vis. spectra, the formation of the charge-transfer complex occurred not immediately but rather slowly. From the magnetic susceptibility measurement, we confirmed the charge-transfer complex is a single-molecule magnet.

该项目的目标是开发基于Mn12配合物的新型单分子磁体。1）Mn12配合物的化学改性。Mn12配合物被称为具有最高阻断温度的单分子磁体，其16个桥联乙酸基团可以被取代。我们尝试用其他羧酸取代桥连乙酸酯基团，例如癸酸、1-金刚烷甲酸、反式-3-(3-噻吩基)丙烯酸、七氟丁酸、二氯乙酸和三氯乙酸对于大多数配体来说都是成功的；所得化合物保留了单分子磁体的典型磁性。它们的温度TB均为2.8 K，略低于Mn12-乙酸盐的3.0 K，但是通过替换乙酸盐获得的化合物。癸酸的磁性表现出反铁磁行为，表明该化合物不是单分子磁体。2）Mn12配合物与各种供体分子的电荷转移配合物的形成我们尝试了Mn12配合物与各种供体分子的电荷转移配合物的形成当我们混合二甲基二苯基四硫氟瓦烯和Mn12-五氟苯甲酸酯络合物的溶液时，会发生TTF型供体分子。形成阳离子TTF衍生物和阴离子Mn12化合物。将二氯甲烷溶液与扩散溶剂静置1周，得到红黑色细小晶体，该溶液的紫外可见光谱在520nm附近显示出强吸收带，摩尔吸收系数为1。根据溶液ESR、NMR，ε大于30000，这可以归因于Mn12阴离子和TTF衍生阳离子之间的电荷转移带。和紫外可见光谱，电荷转移复合物的形成不是立即发生的，而是缓慢发生的。从磁化率测量中，我们证实电荷转移复合物是单分子磁体。