Speaker: Prof. Junzhi LIU

Institution: Department of Chemistry, State Key Laboratory of Synthetic Chemistry, The University of Hong Kong

Hosted By: Prof. Ding PAN

Abstract

Incorporation of the non-hexagonal rings into graphene molecules (NGs) can significantly affect their electronic and optoelectronic properties, as well as the chemical reactivities.[1-4] In this abstract, we will introduce the bottom-up organic synthesis of graphene molecules with non-alternant topologies (Figure 1), e.g. seven-five-seven-membered rings (7-5-7) and four continuous heptagons. To gain new insight into the effect on their electronic and optical properties, various experimental measures, including cyclic voltammetry, Raman, steady UV-vis absorption, and theoretical calculations were carried out. Compared with the aromatics with only hexagonal rings, the NGs with non-alternant topologies present distinct anti-aromatic character with narrower HOMO-LUMO energy gaps. In contrast to the successes achieved with varied NGs with non-alternant topologies, we also try to the development of facile and effective methods to synthesize lovely molecules bearing N-doped joined nonhexagons, including pentagon-heptagon pairs and pentagon-octagon pairs. Our work not only provides a new way to the synthesis of novel graphene molecules with non-alternant topologies, but also offers the possibility to tune their electronic and optical properties.

References:
1. Wang, J.; Gámez, F. G.; Marín-Beloqui, J.; Diaz-Andres, A.; Miao, X.; Casanova, D.; Casado, J.*; Liu, J.* Angew. Chem. Int. Ed. 2023, e202217124. (Featured as Front Cover)
2. Fei, Y.; Liu, J.* Adv. Sci. 2022, 2201000.
3. Wang, J.; Ju, Y. Y.; Low, K. H.; Tan, Y. Z.; Liu, J.* Angew. Chem. Int. Ed. 2021, 60, 11814-11818.
4. Fei, Y.; Fu, Y.; Bai, X.; Du, L.; Li, Z.; Komber, H.; Low, K. H.; Zhou, S.; Phillips, D. L.; Feng, X.; Liu, J.* J. Am. Chem. Soc. 2021, 143, 2353-2360.