Özen Bilal, Fadaei Tirani Farzaneh, Schenk Kurt, Lin Kun-Han, Scopelliti Rosario, Corminboeuf Clémence, Frauenrath Holger
École Polytechnique Fédérale de Lausanne (EPFL), Institute of Materials, Laboratory of Macromolecular and Organic Materials, EPFL-STI-IMX-LMOM, MXG 037, Station 12, 1015, Lausanne, Switzerland.
BCH 2111, Batochime UNIL, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Avenue Forel 2, 1015, Lausanne, Switzerland.
Chemistry. 2021 Feb 15;27(10):3348-3360. doi: 10.1002/chem.202003113. Epub 2021 Jan 25.
The use of crystal engineering to control the supramolecular arrangement of π-conjugated molecules in the solid-state is of considerable interest for the development of novel organic electronic materials. In this study, we investigated the effect of combining of two types of supramolecular interaction with different geometric requirements, amide hydrogen bonding and π-interactions, on the π-overlap between calamitic π-conjugated cores. To this end, we prepared two series of bithiophene diesters and diamides with methylene, ethylene, or propylene spacers between the bithiophene core and the functional groups in their terminal substituents. The hydrogen-bonded bithiophene diamides showed significantly denser packing of the bithiophene cores than the diesters and other known α,ω-disubstituted bithiophenes. The bithiophene packing density reach a maximum in the bithiophene diamide with an ethylene spacer, which had the smallest longitudinal bithiophene displacement and infinite 1D arrays of electronically conjugated, parallel, and almost linear N-H⋅⋅⋅O=C hydrogen bonds. The synergistic hydrogen bonding and π-interactions were attributed to the favorable conformation mechanics of the ethylene spacer and resulted in H-type spectroscopic aggregates in solid-state absorption spectroscopy. These results demonstrate that the optoelectronic properties of π-conjugated materials in the solid-state may be tailored systematically by side-chain engineering, and hence that this approach has significant potential for the design of organic and polymer semiconductors.
利用晶体工程来控制固态下π共轭分子的超分子排列，对于新型有机电子材料的开发具有相当大的吸引力。在本研究中，我们研究了结合两种具有不同几何要求的超分子相互作用——酰胺氢键和π相互作用，对棒状π共轭核之间π重叠的影响。为此，我们制备了两个系列的联噻吩二酯和二酰胺，在联噻吩核与末端取代基中的官能团之间具有亚甲基、乙烯基或丙烯基间隔基。与二酯和其他已知的α,ω-二取代联噻吩相比，氢键连接的联噻吩二酰胺显示出联噻吩核的堆积明显更密集。联噻吩堆积密度在具有乙烯间隔基的联噻吩二酰胺中达到最大值，该联噻吩二酰胺具有最小的纵向联噻吩位移以及由电子共轭、平行且几乎线性的N-H⋅⋅⋅O=C氢键构成的无限一维阵列。氢键和π相互作用的协同作用归因于乙烯间隔基有利的构象力学，并在固态吸收光谱中产生了H型光谱聚集体。这些结果表明，固态下π共轭材料的光电性能可通过侧链工程进行系统调整，因此这种方法在有机和聚合物半导体设计方面具有巨大潜力。
