Breaking a molecular symmetry via self-assembly in an artificial hydrogen-bonded supramolecular system

　Self-assembly behavior of small molecular components has been widely seen in nature, which typically gives highly symmetric architectures. This reason for the high symmetry lies behind the principle that molecular self-assembly proceeds together with large entropy loss. The increasing the number of independent molecular unit with the chemically and physically equivalent position effectively suppresses the entropy loss in the self-assembly process, providing a symmetric structure as a thermodynamically favored product. Thus, multi-component self-assembly forming a C1-symmetric structure is basically challenging owing to the large entropic disadvantage.

　The collaborative research by Prof. Keisuke Umakoshi and Assist. Prof. Shinnosuke Horiuchi from Nagasaki University, Prof. Guido H. Clever from TU Dortmund University, Prof. Eric Meggers from Philipps Universität, Marburg, Germany, and their colleagues have found a formation of a defined C1 symmetric self-assembled product and the significant photophysical properties based on the low-symmetric structure by circularly polarized luminescence (CPL) studies. A key to construct the low-symmetric assembly is a synergistic effect of weak interactions between the components, as inspired from self-assembly of large biomolecules. This result would provide a useful methodology to bring more complexity and flexibility into self-assembled nano systems. This result has been published on 11th Jan 2023 in Nature Communications.

■Original Paper: 
“Symmetry-Breaking Host–guest Assembly in a Hydrogen-bonded Supramolecular System”
S. Horiuchi, T. Yamaguchi, J. Tessarolo, H. Tanaka, E. Sakuda, Y. Arikawa, E. Meggers, G. H. Clever, K. Umakoshi
Nat. Commun. 14, 155 (2023). https://doi.org/10.1038/s41467-023-35850-4

List