Initiating Electron Transfer in Doubly Curved Nanographene Upon Supramolecular Complexation of C60

• Published in: Angewandte Chemie International Edition Vol. 61; no. 7; pp. e202112834 - n/a
• Main Authors: Zank, Simon, Fernández‐García, Jesús M., Stasyuk, Anton J., Voityuk, Alexander A., Krug, Marcel, Solà, Miquel, Guldi, Dirk M., Martín, Nazario
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 07.02.2022; John Wiley and Sons Inc
• Edition: International ed. in English
• Subjects: Benzonitrile; curved nanographenes; DFT; Electron transfer; Electrons; fullerene; New species; NMR; Nuclear magnetic resonance; Stoichiometry; supramolecular complexation; Titration
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202112834

The formation of supramolecular complexes between C60 and a molecular nanographene endowed with both positive and negative curvatures is described. The presence of a corannulene moiety and the saddle shape of the molecular nanographene allows the formation of complexes with 1:1, 1:2, and 2:1 stoichiometries. The association constants for the three possible supramolecular complexes were determined by 1H NMR titration. Furthermore, the stability of the three complexes was calculated by theoretical methods that also predict the photoinduced electron transfer from the curved nanographene to the electron acceptor C60. Time‐resolved transient absorption measurements on the ns‐time scale showed that the addition of C60 to NG‐1 solutions and photo‐exciting them at 460 nm leads to the solvent‐dependent formation of new species, in particular the formation of the one‐electron reduced form of C60 in benzonitrile was observed. Concave–convex interactions between negatively and positively curved molecular nanographene with C60 allow the formation of complexes with 1:1, 1:2, and 2:1 stoichiometries. Theoretical calculations predict the photoinduced electron transfer from the curved nanographene to the electron acceptor C60. Transient absorption spectroscopy confirms solvent dependent electron transfer after photo‐excitation.