Resonance-Enhanced Charge Delocalization in Carbazole-Oligoyne-Oxadiazole Conjugates

Zieleniewska A, Zhao X, Bauroth S, Wang C, Batsanov AS, Krick Calderon C, Kahnt A, Clark T, Bryce MR, Guldi DM (2020)

Publication Type: Journal article

Publication year: 2020

Journal

Book Volume: 142

Pages Range: 18769-18781

Journal Issue: 44

DOI: 10.1021/jacs.0c04003

Abstract

There are notably few literature reports of electron donor-acceptor oligoynes, even though they offer unique opportunities for studying charge transport through "all-carbon" molecular bridges. In this context, the current study focuses on a series of carbazole-(C≡C)n-2,5-diphenyl-1,3,4-oxadiazoles (n = 1-4) as conjugated π-systems in general and explores their photophysical properties in particular. Contrary to the behavior of typical electron donor-acceptor systems, for these oligoynes, the rates of charge recombination after photoexcitation increase with increasing electron donor-acceptor distance. To elucidate this unusual performance, we conducted detailed photophysical and time-dependent density functional theory investigations. Significant delocalization of the molecular orbitals along the bridge indicates that the bridging states come into resonance with either the electron donor or acceptor, thereby accelerating the charge transfer. Moreover, the calculated bond lengths reveal a reduction in bond-length alternation upon photoexcitation, indicating significant cumulenic character of the bridge in the excited state. In short, strong vibronic coupling between the electron-donating N-arylcarbazoles and the electron-accepting 1,3,4-oxadiazoles accelerates the charge recombination as the oligoyne becomes longer.

Authors with CRIS profile

Involved external institutions

Durham University United Kingdom (GB) Leibniz-Institute für Oberflächenmodifizierung e. V. (IOM) / Leibniz Institute of Surface Modification Germany (DE)

How to cite

APA:

Zieleniewska, A., Zhao, X., Bauroth, S., Wang, C., Batsanov, A.S., Krick Calderon, C.,... Guldi, D.M. (2020). Resonance-Enhanced Charge Delocalization in Carbazole-Oligoyne-Oxadiazole Conjugates. Journal of the American Chemical Society, 142(44), 18769-18781. https://dx.doi.org/10.1021/jacs.0c04003

MLA:

Zieleniewska, Anna, et al. "Resonance-Enhanced Charge Delocalization in Carbazole-Oligoyne-Oxadiazole Conjugates." Journal of the American Chemical Society 142.44 (2020): 18769-18781.

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