Structures and Transport Properties of New Molecular Conductors Based on TMEO-ST-TTP

✍ Scribed by Yohji Misaki; Masateru Taniguchi; Kazuyoshi Tanaka; Kazuo Takimiya; Atsushi Morikami; Tetsuo Otsubo; Takehiko Mori

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 318 KB
• Volume: 168
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2002.9758

✦ Synopsis

Several radical cation salts based on TMEO-ST-TTP (2-[4,5bis(methylthio)-1,3-diselenol-2-ylidene]-5-(4,5-ethylendioxy-1,3dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene) have been prepared. X-ray structure analyses of (TMEO-ST-TTP) 2 X (X=PF 6 , AsF 6 , TaF 6 ) reveal that they have the so-called b-type array of donors with dimerized stacks. A tight-binding band calculation suggests that the present salts have a quasi-one-dimensional Fermi surface. On the other hand (TMEO-ST-TTP)Au(CN) 2 has strongly dimerized one-dimensional electronic structure. (TMEO-ST-TTP) 2 X (X=PF 6 , AsF 6 , TaF 6 ) exhibit a high conductivity of r rt ¼ 10 0 210 1 S cm À1 , and retain metallic conductivity down to 4.2 K, while the tetrahedral (ReO À 4 ) and linear (I À 3 and AuðCNÞ À 2 ) anions give semiconductors. Thermoelectric power of (TMEO-ST-TTP) 2 PF 6 shows T-linear temperature dependence characteristic of a metal.