A series of phenyl end-capped α-oligothiophenes containing four to seven thiophene subunits (4T–7T) was synthesized utilizing palladium-catalyzed cross-coupling reactions. UV/Vis spectroscopic analysis revealed one broad absorption band that shifts bathochromically with increasing number of thiophene units. Structured emission spectra are observed with Stokes shift ν~4000 cm⁻¹ and quantum yields of up to 53%. End-capping of the oligothiophene molecules by phenyl units does not only extend the effective conjugation but also prevents from α–α-homocoupling upon electrochemical oxidation. Accordingly, reversible redox waves are observed in cyclic voltammetry with up to four reversible one-electron processes for the two longer congeners. Analyses of the first two oxidation processes in the framework of multiredox systems provide insight into the stabilization or destabilization of polaronic and bipolaronic states. An unusual zig-zag trend for the first (and to a lesser extend second) oxidation process could be explained by the sterical encumbrance of solubilizing hexyl chains in 5T and 7T molecules which counteract the formation of a fully planar quinoidal oligothiophene backbone.

利用钯催化的交叉偶联反应，合成了一系列含4至7个噻吩亚基（4T – 7T）的苯基末端封端的α-寡聚噻吩。UV / Vis光谱分析显示出一个宽吸收带，该吸收带随着噻吩单元数量的增加而向红移。斯托克斯位移ν〜4000 cm ^-1观察到结构发射光谱量子产率高达53％。通过苯基单元对低聚噻吩分子进行封端不仅可以扩展有效的共轭作用，而且还可以防止电化学氧化时的α–α均质偶联。因此，对于两个较长的同类物，在循环伏安法中观察到可逆的氧化还原波，具有多达四个可逆的单电子过程。在多氧化还原系统的框架内对前两个氧化过程的分析提供了对极化和双极化状态的稳定或去稳定的见解。第一次（和次要的第二次氧化）氧化过程出现不寻常的锯齿形趋势，可以用在5T和7T中溶解己基链的空间位阻来解释。 分子，它们抵消了完全平面的喹啉寡噻吩骨架的形成。