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。