Syntheses, structure and properties of vinylogous EDO-TTFs

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• 作者：T. Shirahata ; T. Morikawa ; H. Miyamoto ; Y. Nakano ; H. Yamochi ; Y. Misaki
• 关键词：π ; -Extended donors ; Redox properties ; CT complexes ; Molecular conductors ; X-ray crystal structure analyses
• 刊名：Physica B
• 出版年：2010
• 出版时间：1 June 2010
• 年：2010
• 卷：405
• 期：11, Supplement 1
• 页码：S61-S64
• 全文大小：657 K

文摘

We synthesized vinylogous 4,5-ethylenedioxy-tetrathiafulvalenes (EDO-TTFs), 4,5-ethylenedioxy-2,2′-ethanediylidenebis(1,3-dithiole) (EDO-EBDT), 4,5-dimethyl-4′,5′-ethylenedioxy-2,2′-ethanediylidenebis(1,3-dithiole) (DMEDO-EBDT), 4,5-bis(thiomethyl)-4′,5′-ethylenedioxy-2,2′-ethanediylidenebis(1,3-dithiole) (BTMEDO-EBDT), and 4,5-bis(methoxycarbonyl)-4′,5′-ethylenedioxy-2,2′-ethanediylidenebis(1,3-dithiole) (BMCEDO-EBDT). The cyclic voltammograms of the vinylogous EDO-TTFs show two pairs of single-electron redox waves. The first oxidation potentials (E₁) of vinylogous EDO-TTFs are lower than those of the related TTFs, indicating that the electron donating abilities of new donors are stronger than those of the corresponding TTFs. The smaller E₂−E₁ values of new donors compared with those of the related TTFs suggest a decrease in the on-site Coulombic repulsion in the dication state. X-ray crystal structure analysis of BMCEDO-EBDT reveals that the inter-molecular C-HO type hydrogen bond is constructed between the hydrogen atom and the oxygen atom of the ethylenedioxy group. Single crystalline TCNQ complexes of DMEDO-EBDT and BTMEDO-EBDT have been prepared and their conducting properties and crystal structure have been investigated. The TCNQ complexes of DMEDO-EBDT and BTMEDO-EBDT show low electrical conductivities (σ_rt<10⁻⁶ S cm⁻¹ for (DMEDO-EBDT)(TCNQ)(chlorobenzene) and σ_rt=2.2×10⁻³ S cm⁻¹ for (BTMEDO-EBDT)(TCNQ)) due to DDAA-type alternate stacking.