Chiral Recognition Mechanism of Two-Dimensional Self-Assembly Formed by [7]Thiaheterohelicene

We have investigated the chiral recognition behavior leading to the formation of self-assembled zigzag chain structures of rac-[7]thiaheterohelicene on the Ag(111) surface by density functional theory (DFT) calculations and molecular dynamics (MD) simulations. The DFT calculations showed a weak interaction between the molecule and the Ag surface, indicating that the molecule was fully physisorbed on the surface. On the other hand, the MD simulations provided meaningful insight into the initial formation process of the ordered structures, which strongly supported the experimental observations. We found that the heterochiral dimer, combining through π–π interaction, formed as the crucial building block for long-range zigzag chains, where different enantiomers were arranged alternately. The interaction among neighboring chains was also elucidated, showing the most preferable arrangement of 2D ordered structures.