Helical fused 1,2:8,9-dibenzozethrene oligomers with up to 201 & DEG; end-to-end twist: one-pot synthesis and chiral resolution

Twisted polyarenes with persistent chirality are desirable but their synthesis has remained a challenge. In this study, we present a one-pot synthesis of 1,2:8,9-dibenzozethrene (DBZ) and its vertically fused dimers and trimers using nickel-catalyzed cyclo-oligomerization reactions. X-ray crystallographic analysis confirmed highly twisted helical structures that consist of equal parts left- and right-handed enantiomers. Notably, the end-to-end twist between the terminal anthracene units measured 66 & DEG;, 130 & DEG;, and 201 & DEG; for the DBZ monomer, dimer, and trimer, respectively, setting a new record among twisted polyarenes. Furthermore, the chiral resolution by HPLC yielded two enantiomers for the fused DBZ dimer and trimer, both of which maintained stable configurations and showed absorption dissymmetry factors of around 0.008-0.009. Additionally, their optical and electrochemical properties were investigated, which exhibited a chain-length dependence.

Automated summary

This study presents a one-pot synthesis of twisted polyarenes using nickel-catalyzed cyclo-oligomerization reactions. The highly twisted helical structures consist of equal parts left- and right-handed enantiomers. Chiral resolution yielded two stable enantiomers with absorption dissymmetry factors of around 0.008-0.009.