Syntheses and new development of nano scale magnetic molecules

具有易轴型各向异性的高自旋分子在很低的温度下表现出非常缓慢的磁化热弛豫，并且表现为单畴磁体，因此引起了人们的极大兴趣。这种分子被归类为单分子磁体(SMM)。此外，由于它们离散的自旋能级，可以观察到宏观的量子磁化隧穿(QTM)。在具有恒定磁场间隔的十二核锰团簇([Mn12])中首次观察到了磁滞回环中的量子弛豫现象。量子光学模型的研究不仅对量子物理的基础和理论研究具有重要意义，而且对量子计算的可能应用也具有重要意义。我们研究了制备具有高自旋基态的多核金属配合物。在本研究项目中，我们将我们的合成策略应用到SMM的制备中，制备了以下配合物。(1)异质金属自组装材料：…的合成更多的杂金属络合物被认为可以制备具有适合不同金属离子的配位的桥联配体。我们发现，在一锅法合成中，三齿席夫碱与两种不同的金属离子反应生成了杂金属配合物。[Mn^&lt；III&gt；Cu^&lt；II&gt；]，[Mn^&lt；III&gt；_2m_2](M=铜和镍)和[Mn^&lt；III&gt；_2Tb；&lt；III&gt；_2]具有高自旋基态，经交流磁化率测量证明是自旋金属。(2)具有钙钛矿结构的混合价锰氧化物由于固体中的巡游电子而显示出有趣的物理性质。我们发现，五配位的席夫碱配体与锰、铜离子反应生成了具有氧化物桥联金属核的同金属和杂金属大簇合物。[Mn^&lt；III&gt；_&lt；12&gt；Mn_V]的同金属络合物中混合了13个锰离子，其中一些是由氧化物离子桥联的。该分子呈现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。这些体系是制备氧化物分子簇的独特方法，这些合成方法有助于探索由于混合价而可能显示出有趣的固态性质的新的复杂分子。较少

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