Three selenium analogues of DTEDT [2-(1,3-dithiol-2-ylidene)-5-[2-(1,3-dithiol-2-ylidene)ethylidene]-1,3,4,6-tetrathiapentalene] have been synthesized. They showed four pairs of single-electron redox waves. The E1 values are a little higher by 0.02–0.05 V than that of DTEDT. On the other hand, the E2−E1 values are almost equal to that of DTEDT. Their TCNQ complex and cation radical salts show fairly high electrical conductivities and several salts exhibit metallic conductivities. In particular the ReO4− and Au(CN)2− salts of DTEDS and the SbF6−, TaF6− and I3− salts of DSEDS exhibited stable metallic behaviour down to 1.5–4.2 K. An X-ray crystal structure analysis of the metallic salt (DSEDS)3TaF6 reveals that this salt has a two-dimensional β-type packing motif of the donor molecules similar to the superconducting (DTEDT)3Au(CN)2. The calculated Fermi surface of (DSEDS)3TaF6 is a two-dimensional closed ellipsoid.
我们合成了 DTEDT [2-(1,3-二
硫醇-2-亚基)-5-[2-(1,3-二
硫醇-2-亚基)亚乙基]-1,3,4,6-四
硫杂
戊烯] 的三种
硒类似物。它们显示了四对单电子氧化还原波。E1 值比 DTEDT 略高 0.02-0.05 V。另一方面,E2-E1 值几乎与 DTEDT 相等。它们的 TCNQ 复合物和阳离子自由基盐显示出相当高的导电性,而且有几种盐显示出
金属导电性。特别是 DTEDS 的 ReO4- 盐和 Au(CN)2- 盐以及 D
SEDS 的 SbF6- 盐、TaF6- 盐和 I3- 盐在 1.5-4.2 K 温度下表现出稳定的
金属特性。对
金属盐 (D
SEDS)3TaF6 的 X 射线晶体结构分析表明,这种盐具有与超导 (DTEDT)3Au(CN)2 相似的供体分子二维 β 型堆积结构。计算得出的 (D
SEDS)3TaF6 费米面是一个二维封闭椭圆体。