1,1,4,4-Tetra(2-furyl, 2-thienyl, and 2-selenienyl)butatrienes: Synthesis, Properties, and Molecular Structures
作者:Hiroyuki Kurata、Seiji Muro、Tetsuya Enomoto、Takeshi Kawase、Masaji Oda
DOI:10.1246/bcsj.80.349
日期:2007.1.15
Tetra(2-furyl, 2-thienyl, and 2-selenienyl)butatrienes and their derivatives have been prepared by dimerization of ate-type complexes derived from the corresponding 1,1-dichloro-2,2-diarylethenes using appropriate copper complexes in moderate to high yields. These new butatrienes are relatively stable crystalline substances with intense absorption bands at long wavelengths. The electronic properties of the substituents at the 5-position of aryl groups remarkably influence the wavelength of the longest absorption and the π-electron distribution of butatriene moiety. Their redox potentials, measured by cyclic voltammetry, have higher amphoteric redox properties than those of tetraphenylbutatriene. The crystal structures of tetrakis(5-trimethylsilyl)-substituted derivatives show the following two features: (1) the thiophene and selenole derivatives have pseudo-D2 structures, while the furan derivative has a C2 symmetric structure probably due to the counterbalance between the energy of conjugation and the nonbonded chalcogen–chalcogen interaction; (2) the central double bonds of these butatrienes are considerably short.
通过使用适当的铜配合物,在适中至高产率下,将相应的1,1-二氯-2,2-二芳基乙烯的ate型复合物进行二聚化反应,已制备得到四(2-呋喃基、2-噻吩基和2-硒吩基)丁三烯及其衍生物。这些新型丁三烯化合物为相对稳定的晶体物质,具有长波长处强烈的吸收带。芳基5位取代基的电子性质显著影响丁三烯部分的波长最长吸收及π电子分布。通过循环伏安法测得的其氧化还原电位,相比于四苯基丁三烯,显示出更高的两性氧化还原性质。四(5-三甲基硅基)取代衍生物的晶体结构显示以下两个特点:(1)噻吩和硒吩衍生物具有伪D2结构,而呋喃衍生物具有可能由于共轭能与非键合的硫/硒相互作用之间的平衡导致的C2对称结构;(2)这些丁三烯的中心双键相当短。