Crystal structures and physical properties of single-component molecular conductors consisting of nickel and gold complexes with bis(trifluoromethyl)tetrathiafulvalenedithiolate ligands
Crystal structures and physical properties of single-component molecular conductors consisting of nickel and gold complexes with bis(trifluoromethyl)tetrathiafulvalenedithiolate ligands
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DOI：
10.1039/b413597k
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发表时间：
2005-12
影响因子：
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通讯作者：
M. Sasa;E. Fujiwara;A. Kobayashi;S. Ishibashi;K. Terakura;Y. Okano;H. Fujiwara;H. Kobayashi
中科院分区：
文献类型：
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作者：
M. Sasa;E. Fujiwara;A. Kobayashi;S. Ishibashi;K. Terakura;Y. Okano;H. Fujiwara;H. Kobayashi
为了研究开发可溶于有机溶剂的单组分分子导体的可能性，制备了具有双（三氟甲基）四硫富瓦烯二硫醇配体的中性镍和金配合物[M(hfdt)2]（M = Ni，Au）。然而，与之前的报告相反，晶体在通常的有机溶剂中没有表现出任何溶解度。另一方面，晶体结构分析显示出独特的二维层状结构，尽管单组分分子导体通常倾向于采取紧凑的三维分子排列。每层由末端CF3基团分隔，形成“CF3双层结构”。最短分子间 F⋯F 距离（[Ni(hfdt)2] 为 3.018 A，[Au(hfdt)2] 为 2.862 A) 明显长于范德华 F⋯F 距离 (2.70 A)，并且 CF3 双层区域周围前沿电子的分布几乎为零。这是由于强烈的 F⋯F 偏聚效应，这将为控制单组分分子导体中的分子聚集提供有效的方法。对[Ni(hfdt)2]进行了扩展Huckel紧束缚能带结构计算和从头算局域密度近似(LDA)能带结构计算，解释了系统的半导体和非磁性特性。还对 [Au(hfdt)2] 进行了扩展休克尔紧束缚能带结构计算。计算出的能带结构与[Au(hfdt)2]的半导体和几乎非磁性特性一致。
The neutral nickel and gold complexes with bis(trifluoromethyl)tetrathiafulvalenedithiolate ligands, [M(hfdt)2] (M = Ni, Au) were prepared in order to examine the possibility of the development of single-component molecular conductors soluble in organic solvents. However, in contrast to the previous report, the crystals did not show any solubility in the usual organic solvents. On the other hand, the crystal structure analyses showed unique two-dimensional layered structures, despite that the single-component molecular conductors usually tend to take a compact three-dimensional molecular arrangement. Each layer is separated by the terminal CF3 groups to form the “CF3 bilayer structure”. The shortest intermolecular F⋯F distance (3.018 A for [Ni(hfdt)2] and 2.862 A for [Au(hfdt)2]) is significantly longer than the van der Waals F⋯F distance (2.70 A) and the distribution of the frontier electrons is almost zero around the CF3 bilayer region. This is due to the strong F⋯F segregation effect, which will provide a useful way to control the molecular aggregation in the single-component molecular conductors. Extended-Huckel tight-binding band structure calculations and the ab initio local density approximation (LDA) band structure calculations were made for [Ni(hfdt)2], which explains the semiconducting and non-magnetic properties of the system. Extended-Huckel tight-binding band structure calculations were also made for [Au(hfdt)2]. The calculated band structure is consistent with the semiconducting and almost non-magnetic properties of [Au(hfdt)2].