RT Journal Article
T1 Helical Bilayer Nanographenes: Impact of the Helicene Length on the Structural, Electrochemical, Photophysical, and Chiroptical Properties
A1 Martín, Nazario
A1 Fernández García, Jesús Manuel
A1 Medina Rivero, Samara
A1 Šámal, Michal
A1 Izquierdo García, Patricia
A1 Rybáček, Jiří
A1 Bednárová, Lucie
A1 Ramírez, Francisco J.
A1 Ramírez-Barroso, Sergio
A1 Rodríguez, Rafael
A1 García-Fresnadillo, David
A1 Perles Hernáez, Josefina
A1 Crassous, Jeanne
A1 Casado, Juan
A1 Stará, Irena G.
AB Helical bilayer nanographenes (HBNGs) are chiral πextended aromatic compounds consisting of two π−π 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 π−π 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 π-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 glum (3.6 × 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.
LK https://hdl.handle.net/20.500.14352/65320
UL https://hdl.handle.net/20.500.14352/65320
LA eng
NO PMID: 37129470
DS Docta Complutense
RD 12 abr 2025