Syntheses and new development of nano scale magnetic molecules

具有易轴型各向异性的高自旋分子由于在低温下表现出非常慢的磁化热弛豫，表现为单畴磁体而引起人们的广泛兴趣。这种分子被归类为单分子磁体（SMM）。此外，由于它们的离散自旋能级，可以观察到宏观量子磁化隧穿（QTM）。首次在十二核锰团簇（[Mn 12]）中观察到磁滞回线中磁场间隔一定时的台阶状量子弛豫现象。QTM的研究不仅对量子物理的基础和理论研究有重要意义，而且对量子计算的可能应用也有重要意义。我们研究了高自旋基态多核金属配合物的制备。在本研究项目中，我们将我们的合成策略应用于SMMs的制备，制备了以下配合物。(1)杂金属SMMs的合成 ...更多信息 F杂金属络合物被认为可制备具有适合于不同金属离子的配位位点的桥接配体。我们发现三齿席夫碱与两种不同的金属离子反应，在一锅法合成中得到了杂金属配合物。[Mn[Cu ^]、[Mn ^_2M_2]（M = Cu和Ni）和[Mn ^_2Tb ^_2]具有高自旋基态，并且已经通过交流磁化率测量被证明是SMM。<III><II><III><III><III>(2)由于固体中的巡游电子，具有Percent结构的混合价锰氧化物显示出有趣的物理性质。我们发现，五配位席夫碱配体与Mn和Cu离子的反应产生了具有氧化物桥连金属核的同金属和异金属大簇分子。[Mn ^_Mn_V]的同金属配合物具有混合价的十三个锰离子，其中一些由氧离子桥接。<III><12>该分子表现出准可逆的四步四电子氧化还原波，分离出一个和两个氧化态，并对其结构和磁性进行了研究。该体系是制备氧化物分子团簇的独特方法，这种合成方法有助于探索新的复杂分子，这些分子可能由于混合价态而表现出有趣的固态性质。少

High spin molecules with an easy-axis type anisotropy are attracted much interest because they show very slow thermal relaxation of magnetization at very low temperature, and behave as single-domain magnet. Such molecules are classified as single-molecule magnets (SMMs). Furthermore, it is possible to observe macroscopic quantum tunneling of magnetization (QTM) due to their discreet spin energy levels. The relaxation phenomenon via quantum process was first observed in dodecanuclear manganese cluster ([Mn12]) as steps with constant intervals of magnetic field in a magnetic hysteresis roop. The study of QTM is important for not only fundamental and theoretical study of quantum physics, but also for the possible applications for quantum computing. We have studied to prepare multinuclear metal complexes with high-spin ground states. In this research project, we applied our synthetic strategies to the preparation of SMMs and prepared following complexes. (1) Hetero-metal SMMs : Syntheses o … More f hetero-metal complexes have been believed to prepare bridging ligands having coordination sites suitable for different metal ions. We have found that reactions of tridentate Schiff bases with two different metal ions yielded hetero-metal complexes in one-pot syntheses. [Mn^<III>Cu^<II>], [Mn^<III>_2M_2] (M=Cu and Ni), and [Mn^<III>_2Tb^<III>_2] have high-spin ground states and have been proven to be SMMs by ac magnetic susceptibility measurements. (2) Mixed valent manganese oxide with a Perovskite structure showed interesting physical properties due to itinerant electrons in solids. We have found that reactions of pentacoordianted Schiff base ligands with Mn and Cu ions yielded homo and hetero-metal large cluster molecules having oxide bridged metal cores. A homo-metal complex of [Mn^<III>_<12>Mn_V] has mixed valent thirteen manganese ions some of which are bridged by oxide ions. This molecule show quasi-reversible four-steps four-electron redox waves and one and two oxidation states were isolated, and their structures and magnetic properties were studied. The systems are unique methods to prepare oxide molecular clusters, and this synthetic methods help to explore new complex molecule which might show interesting solid state properties due to mixed valence. Less