Persistent peri-Heptacene: Synthesis and In Situ Characterization

Abstract

n-peri-Acenes (n-PAs) have gained interest as model systems of zigzag-edged graphene nanoribbons for potential applications in nanoelectronics and spintronics. However, the synthesis of n-PAs larger than peri-tetracene remains challenging because of their intrinsic open-shell character and high reactivity. Presented here is the synthesis of a hitherto unknown n-PA, that is, peri-heptacene (7-PA), in which the reactive zigzag edges are kinetically protected with eight 4-tBu-C6H4 groups. The formation of 7-PA is validated by high-resolution mass spectrometry and in situ FT-Raman spectroscopy. 7-PA displays a narrow optical energy gap of 1.01 eV and exhibits persistent stability (t1/2≈25 min) under inert conditions. Moreover, electron-spin resonance measurements and theoretical studies reveal that 7-PA exhibits an open-shell feature and a significant tetraradical character. This strategy could be considered a modular approach for the construction of next-generation (3 N+1)-PAs (where N≥3). © 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH

Description
Keywords
Scholl reaction, acenes, graphene, nanostructures, radicals
Citation
Ajayakumar, M. R., Ma, J., Lucotti, A., Schellhammer, K. S., Serra, G., Dmitrieva, E., et al. (2021). Persistent peri-Heptacene: Synthesis and In Situ Characterization. 60(25). https://doi.org//10.1002/anie.202102757
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License
CC BY-NC-ND 4.0 Unported