A comprehensive investigation of two new molecular triads incorporating the diketopyrrolopyrrole unit into a quinoidized thienothiophene skeleton, which is further end‐capped with dicyanomethylene (DPP‐TT‐CN) or phenoxyl groups (DPP‐TT‐PhO), has been carried out. A combination of UV‐Vis‐NIR and infrared spectroelectrochemical techniques and cryogenic UV‐Vis‐NIR absorption spectroscopy supported by theoretical calculations has been used. The main result is the formation of similar H‐aggregates in the dimerization process of the neutral molecules and of the charged anionic species. The experimental absorption spectra of the aggregated species are accurately reproduced by quantum chemical calculations using the Spano’s model, including excitonic coupling for the dimeric forms and full vibronic resolution of the absorption bands. The strong excitonic coupling taking place is key to understand the electronic structure of the dimeric aggregates and has been instrumental to disentangle the type of H‐aggregation. This study is of relevance to get a better understanding of the molecular aggregation of organic p‐conjugated chromophores and is useful as a guideline for the refinement of the engineering of molecular materials for which supramolecular design is required.

中文翻译：

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醌型噻吩并噻吩二酮吡咯并吡咯的中性和阴离子物种表现出共同的聚集模式


对两种新的分子三联体进行了全面研究，将二酮吡咯并吡咯单元合并到醌型噻吩并噻吩骨架中，并进一步用二氰亚甲基（DPP-TT-CN）或苯氧基（DPP-TT-PhO）封端。结合了紫外-可见-近红外和红外光谱电化学技术以及由理论计算支持的低温紫外-可见-近红外吸收光谱。主要结果是在中性分子和带电阴离子物质的二聚过程中形成类似的 H 聚集体。使用 Spano 模型通过量子化学计算准确再现了聚集物质的实验吸收光谱，包括二聚体形式的激子耦合和吸收带的全振动分辨率。发生的强激子耦合是理解二聚体聚集体电子结构的关键，并且有助于解开 H 聚集体的类型。这项研究有助于更好地理解有机 p 共轭发色团的分子聚集，并可作为细化需要超分子设计的分子材料工程的指南。