Design of Novel Superconductors and Magnetic Conductors Based on Stepwise π-Stacking Structures

在最初设计的逐步堆积的基础上，利用酞菁(Pc)与轴向CN配体的络合物来开发新型导体。当中心金属离子无磁性时，可以得到正常的导体，而当有磁性时，可以得到磁性导体。[Co^&lt；III&gt；(Pc)(CN)_2]^-电化学氧化生成中性自由基物种，其中Pc配体成为开壳结构。由该物种单独构成的晶体的导电性不高，而与溶剂分子的共晶由于有效的π-π堆积而改善了导电性。根据溶剂种类的不同，得到了不同的堆积结构。由于电子关联效应，中性自由基晶体是半导体，而用阴离子(部分氧化盐)结晶则是金属导体。它们的形成取决于阳离子物种和具有不同π-π堆积…的六种部分氧化盐得到了更多的结构。其中，具有双二维结构的晶体在高温高压下保持了金属性质。[Co^&lt；III&gt；(Pc)(CN)_2]^-的电化学氧化得到了与Co盐同象的晶体。对于一维体系，详细研究了Co和Fe盐的物理性质。基于热电功率和光学反射率的测量发现，电子结构是相同的。而Co盐的电导率几乎不变，而Fe盐在低温下表现出绝缘行为。这是由于在Pc环中心存在周期性排列的磁矩所致。作为一个重要的结果，我们发现外加磁场会降低材料的电阻率。不同寻常的是，这样的一维系统显示出“巨负磁阻”。较少

Phthalocyanine (Pc) complexes with axial CN ligands were utilized for development of novel conductors based on the originally devised stepwise stacking. When the central metal ion is nonmagnetic Co^<III> normal conductors can be obtained, while when it is magnetic Fe^<III> magnetic conductors can be obtained.Electrochemical oxidation of [Co^<III>(Pc)(CN)_2]^- yields the neutral radical species in which the Pc ligand becomes open-shell structure. The crystal constructed solely with this species was not highly conducting while co-crystallization with solvent molecules improved the conductivity due to the efficient π-π stacking. Various stacking structures depending on the solvent species have been obtained. The neutral radical crystals are semiconductors due to the electron correlation effect, while crystallization with the anion (partially oxidized salt) gage metallic conductors. Their formation depends on the cationic species, and six partially oxidized salts with various π-π stacking … More structures have been obtained. Among them the crystal with double two-dimensional sheeto structure has been found to maintain metallic character at low temperatures under high pressure.Electrochemical oxidation of [Co^<III>(Pc)(CN)_2]^- gave isomorphous crystals with the Co salts. For the one-dimensional system, the physical properties of the Co and Fe salts were investigated in detail. Electronic structure was found to be identical based on the thermoelectric power and optical reflectance measurements. On the other hand, the electrical conductivity was found to be dramatically different from each other , the resistivity is almost constant for the Co salt, while it shows insulating behavior at low temperature for the Fe salt. This is due to the existence of periodically arranged magnetic moments at the center of the Pc rings. As an important consequence, we have found that the resistivity decreases by applying external magnetic field. It is unusual that such a one-dimensional system shows "giant negative magnetoresistance". Less