Chiral structures created through the adsorption of molecules onto achiral surfaces play pivotal roles in many fields of science and engineering. Here, we present a systematic study of a novel chiral phenomenon on a surface in terms of organizational chirality, that is, meso-isomerism, through coverage-driven hierarchical polymorphic transitions of supramolecular assemblies of highly symmetric π-conjugated molecules. Four coverage-dependent phases of dehydrobenzo[12]annulene were uniformly fabricated on Ag(111), exhibiting unique chiral characteristics from the single-molecule level to two-dimensional supramolecular assemblies. All coverage-driven phase transitions stem from adsorption-induced pseudo-diastereomerism, and our observation of a lemniscate-type (∞) supramolecular configuration clearly reveals a drastic chiral phase transition from an enantiomeric chiral domain to a meso-isomeric achiral domain. These findings provide new insights into controlling two-dimensional chiral architectures on surfaces.
The present work was supported in part by a Grant-in-Aid for Scientific Research (A) [JP15H02025], the Japan Science and Technology Agency (JST) SICORP [957067], and the RIKEN foreign postdoctoral researcher (FPR) program. It was also partly supported by the Basic Science Research Program through the National Research Foundation of Korea [NRF-2018R1C1B6003122 and NRF-2018R1D1A1B07049304]. We are grateful for the use of the HOKUSAI-GreatWave Supercomputer system of RIKEN.The present work was supported in part by a Grant-in-Aid for Scientific Research (A) [JP15H02025], the Japan Science and Technology Agency (JST) SICORP [957067], and the RIK-EN foreign postdoctoral researcher (FPR) program. It was also partly supported by the Basic Science Research Program through the National Research Foundation of Korea [NRF-2018R1C1B6003122 and NRF-2018R1D1A1B07049304]. We are grateful for the use of the HOKUSAI-GreatWave Supercomputer system of RIKEN.
