Synthesis of New Electron Donor ClMe<sub>3</sub>-TTP: Structures and Properties of (ClMe<sub>3</sub>-TTP)<sub>3</sub>X (X = PF<sub>6</sub> and AsF<sub>6</sub>)
作者:Takashi Shirahata、Shuhei Kohno、Keisuke Furuta、Yusuke Oka、Yohji Misaki
DOI:10.1246/bcsj.20140413
日期:2015.8.15
In this study, we synthesized 2-(4-chloro-5-methyl-1,3-dithiol-2-ylidene)-5-(4,5-dimethyl-1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (ClMe3-TTP). Results show that the cation radical salts of ClMe3-TTP with PF6− and AsF6− anions show high conductivities (101 S cm−1) at room temperature and semiconducting behavior with low activation energy (24–27 meV). A crystal structure analysis of the PF6− and AsF6− salts reveals a 3:1 donor–anion ratio of these salts. The ClMe3-TTP molecules form one-dimensional columns along the a axis, and tape-structures, connected by the side-by-side S···S interactions, also form along the a axis. The calculated intracolumn and intratape overlap integrals are relatively large; however, the overlap integrals between the one-dimensional columns and the tapes are approximately 1/2–1/5 the value of the intracolumn and intratape overlap integrals. The band calculations suggest that they have one-dimensional electronic structures, indicating that they would comprise a Mott insulator.
本研究合成了 2-(4-氯-5-甲基-1,3-二硫醇-2-亚基)-5-(4,5-二甲基-1,3-二硫醇-2-亚基)-1,3,4,6-四硫杂戊烯(ClMe3-TTP)。结果表明,带有 PF6- 和 AsF6- 阴离子的 ClMe3-TTP 阳离子自由基盐在室温下具有高电导率(101 S cm-1)和低活化能(24-27 meV)的半导体特性。对 PF6- 盐和 AsF6- 盐的晶体结构分析表明,这些盐的供体阴离子比例为 3:1。ClMe3-TTP 分子沿 a 轴形成一维柱状,通过并排 S-S 相互作用连接的带状结构也沿 a 轴形成。计算得出的柱内和带内重叠积分相对较大;然而,一维柱和带之间的重叠积分约为柱内和带内重叠积分的 1/2-1/5。能带计算表明,它们具有一维电子结构,表明它们将构成莫特绝缘体。