Prof. Kenji Matsuda, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering Kyoto University    

Design and Synthesis of Molecules with Unique Electronic Function: CPL-Emissive and π-Extended Helicenes and Radical-Substituted Molecular Wire

Helicenes have helically twisted MOs and have attracted attention for their chiroptical properties, but unsubstituted helicene is non-emissive. We designed and synthesized circularly polarized luminescence (CPL)-emissive helicenes with high emission quantum yield and high dissymmetry factor[1]. We also synthesized π-extended helicenes, which show polyene-like electronic structures at the inner rim and the ultrafast decay dynamics attributable to the low-lying conical intersection[2]. As STM handles tunneling current, STM apparent height of a molecule reflects the conductance of the molecule. Two porphyrin complexes with different molecular wires each having different lengths of side chains form different domains in the STM image at the liquid/solid interface, which enables us to measure the apparent height of each molecule separately[3]. Large enhancement of the single-molecular conductance of a molecular wire by a radical substituent was revealed by this method [4].

[1] H. Kubo, T. Hirose, T. Nakashima, T. Kawai, J.-y. Hasegawa, K. Matsuda, J. Phys. Chem. Lett. 2021, 12, 686−695.
[2] Y. Nakakuki, T. Hirose, H. Sotome, M. Gao, D. Shimizu, R. Li, J. Hasegawa, H. Miyasaka, K. Matsuda, Nat. Commun. 2022, 13, 1475.
[3] T. Sakano, K. Higashiguchi, K. Matsuda, Chem. Commun. 2011, 47, 8427–8429.
[4] R. Yasui, D. Shimizu, K. Matsuda, Chem. Eur. J. 2022, 28, e202104242.

Zoom link for online participation:
https://aarhusuniversity.zoom.us/j/63459573558