Conjugation-extended tetrathiafulvalene analogues, 2,5-bis(1,4-dithiafulven-6-yl)thiophene (2a), 2,5-bis[2,3-bis(methoxycarbonyl)-1,4-dithiafulven-6-yl]thiophene, and 2,5-bis(1,4-dithiafulven-6-yl)furan, involving an aromatic heterocyclic linking group have been synthesized by the Wittig condensation reaction of 2,5-thiophene- and 2,5-furandicarbaldehydes with 1,3-dithiol-2-ylidenetributylphosphorane and its 4,5-bis(methoxycarbonyl) derivative. The electrochemical redox properties of these compounds in solution have been investigated by cyclic voltammetry in order to evaluate the effect of the linking group on the donating ability and the thermodynamic stability of the radical cations. Whereas the radical cations are not so stable, complexes of 2a with 2,3-dichloro-5,6-dicyano-p-benzoquinone and iodine were found to show relatively high conductivities ((1.0—1.1) × 10−3 S cm−1) on a compressed pellet at room temperature.
2,5-双(1,4-二
硫杂富烯-6-基)
噻吩(2a)、2,5-双[2,3-双(甲氧基羰基)-1,4-二
硫杂富烯-6-基]
噻吩和 2,5-双(1,4-二
硫杂富烯-6-基)
呋喃的共轭扩展四
硫杂富烯类似物、通过 2,5-
噻吩和 2,5-
呋喃二羰基醛与 1,3- 二
硫醇-2-亚基四丁基
磷烷及其 4,5- 双(甲氧基羰基)衍
生物的维蒂希缩合反应,合成了涉及芳香杂环连接基团的 2,5-
噻吩和 2,5-
呋喃二羰基醛。通过循环伏安法研究了这些化合物在溶液中的电
化学氧化还原特性,以评估连接基团对自由基阳离子的捐献能力和热力学稳定性的影响。2a 与 2,3-二
氯-5,6-二
氰基
对苯醌和
碘的配合物在室温下的压缩颗粒上显示出相对较高的电导率((1.0-1.1) × 10-3 S cm-1),而自由基阳离子则不太稳定。