For their great structural versatility, thiophene-based π-conjugated systems have been widely exploited in the preparation of low band gap materials. Here, we report the synthesis of a highly conjugated tetrathiophene system, namely 1,4-di([2,2′-bithiophen]-3-yl)buta-1,3-diyne (1), that presents two bithiophene units connected at position 3 by a butadiynylene spacer. Single-crystal X-ray diffraction (SC-XRD) analysis elucidated the structure of 1, confirming the planarity of the molecule. The molecule was then electropolymerized onto the surface of a gold-coated piezoelectric quartz crystal, showing a high reactivity that is ascribable to the extended conjugation. The frontier molecular orbital energies of 1 were obtained via DFT optimization performed on the crystal structure-derived molecular geometry. Finally, DFT was also used to estimate the polymer band gap.

中文翻译：

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1,4-二([2,2'-联噻吩]-3-基)丁-1,3-二炔的合成、晶体结构和电聚合


由于其结构的多样性，基于噻吩的π共轭体系已被广泛用于低带隙材料的制备。在这里，我们报道了高度共轭四噻吩系统的合成，即 1,4-di([2,2'-联噻吩]-3-基)buta-1,3-diyne (1)，该系统呈现两个连接的联噻吩单元在位置3处由丁二炔基间隔基连接。单晶X射线衍射（SC-XRD）分析阐明了1的结构，证实了分子的平面性。然后将该分子电聚合到镀金压电石英晶体的表面上，显示出高反应性，这归因于延长的共轭。 1 的前沿分子轨道能量是通过对晶体结构衍生的分子几何形状进行 DFT 优化获得的。最后，DFT 还用于估计聚合物带隙。