Department of Chemistry, Graduate School of Science, The University of Tokyo , 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
J Am Chem Soc. 2014 Oct 15;136(41):14357-60. doi: 10.1021/ja507619d. Epub 2014 Oct 1.
A bulk material comprising stacked nanosheets of nickel bis(dithiolene) complexes is investigated. The average oxidation number is -3/4 for each complex unit in the as-prepared sample; oxidation or reduction respectively can change this to 0 or -1. Refined electrical conductivity measurement, involving a single microflake sample being subjected to the van der Pauw method under scanning electron microscopy control, reveals a conductivity of 1.6 × 10(2) S cm(-1), which is remarkably high for a coordination polymeric material. Conductivity is also noted to modulate with the change of oxidation state. Theoretical calculation and photoelectron emission spectroscopy reveal the stacked nanosheets to have a metallic nature. This work provides a foothold for the development of the first organic-based two-dimensional topological insulator, which will require the precise control of the oxidation state in the single-layer nickel bisdithiolene complex nanosheet (cf. Liu, F. et al. Nano Lett. 2013, 13, 2842).
研究了一种由镍双二硫烯配合物的堆叠纳米片组成的块状材料。在制备的样品中，每个配合物单元的平均氧化数为-3/4；氧化或还原分别可以将其改变为 0 或-1。经过改进的电导率测量，涉及在扫描电子显微镜控制下对单个微薄片样品进行范德堡法，揭示出 1.6×10(2) S cm(-1)的电导率，对于配位聚合物材料来说非常高。电导率也随着氧化态的变化而变化。理论计算和光电子发射光谱表明堆叠的纳米片具有金属性质。这项工作为开发第一个基于有机的二维拓扑绝缘体提供了立足点，这将需要在单层镍双二硫烯配合物纳米片中精确控制氧化态（参见 Liu, F. 等人，Nano Lett. 2013, 13, 2842）。
