Novel conjugated small molecules are highly sought after due to potential applications in organic electronics. Most conjugated materials used in such applications rely on two-directional electron-rich fragments (e.g., 2,5-disubstituted thiophenes). In contrast, tri-directional conjugated compounds are much less well studied, in part due to limitations in chemical synthesis. With the ultimate goal of accessing novel trimeric scaffolds using unusual synthetic transformations, we targeted the class of indole-based trimers. We report the successful trimerization of three isomeric indolynes, which, in turn, permits access to six new bent and planar aromatic indole trimers that display varying photophysical properties. We describe the photophysical properties of these unique compounds, in addition to detailed structural and excited state analyses based on computational studies. Our efforts mark the first reported use of indolynes in transition metal-catalyzed reactions, while providing access to a new class of conjugated trimers, including the most bent fused heteroaromatic compounds to date.

Conjugated trimeric scaffolds accessible using indolyne cyclotrimerizations

253rd National Meeting (2017)

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