Helical Bilayer Nanographenes: Impact of the Helicene Length on the Structural, Electrochemical, Photophysical, and Chiroptical Properties

0572569 - ÚOCHB 2024 RIV US eng J - Journal Article
Izquierdo-Garcia, P. - Fernández-García, J. M. - Rivero, S. M. - Šámal, Michal - Rybáček, Jiří - Bednárová, Lucie - Ramirez-Barroso, S. - Ramirez, F. J. - Rodriguez, R. - Perles, J. - Garcia-Fresnadillo, D. - Crassous, J. - Casado, J. - Stará, Irena G. - Martín, N.
Helical Bilayer Nanographenes: Impact of the Helicene Length on the Structural, Electrochemical, Photophysical, and Chiroptical Properties.
Journal of the American Chemical Society. Roč. 145, č. 21 (2023), s. 11599-11610. ISSN 0002-7863. E-ISSN 1520-5126
R&D Projects: GA ČR(CZ) GA20-23566S
Institutional support: RVO:61388963
Keywords : helical bilayer nanographenes * [9] and [11]helicenes * dissymmetry factors gabs and glum
OECD category: Organic chemistry
Impact factor: 15, year: 2022
Method of publishing: Open access
https://doi.org/10.1021/jacs.3c01088

Helical bilayer nanographenes (HBNGs) are chiral pi- extended aromatic compounds consisting of two pi-pi stacked hexabenzocoronenes (HBCs) joined by a helicene, thus resembling van der Waals layered 2D materials. Herein, we compare [9]HBNG, [10]HBNG, and [11]HBNG helical bilayers endowed with [9], [10], and [11]helicenes embedded in their structure, respectively. Interestingly, the helicene length defines the overlapping degree between the two HBCs (number of benzene rings involved in pi-pi interactions between the two layers), being 26,14, and 10 benzene rings, respectively, according to the X-ray analysis. Unexpectedly, the electrochemical study shows that the lesser pi-extended system [9]HBNG shows the strongest electron donor character, in part by interlayer exchange resonance, and more red-shifted values of emission. Furthermore, [9]HBNG also shows exceptional chiroptical properties with the biggest values of gabs and glu m (3.6 x 10-2) when compared to [10]HBNG and [11]HBNG owing to the fine alignment in the configuration of [9]HBNG between its electric and magnetic dipole transition moments. Furthermore, spectroelectrochemical studies as well as the fluorescence spectroscopy support the aforementioned experimental findings, thus confirming the strong impact of the helicene length on the properties of this new family of bilayer nanographenes.
Permanent Link: https://hdl.handle.net/11104/0343214


Research data: CCDC, CCDC