Double π-Extended Helicene Derivatives Containing Pentagonal Rings: Synthesis, Crystal Analyses, and Photophysics

Two novel double pi-extended [n]helicene (n = 5, 6) derivatives (7b and 9) including pentagonal rings have been synthesized and characterized. Both of them have three isomers containing two enantiomers (P-6), (M-6), and a diastereoisomer in a meso form (P,M). X-ray single crystal analyses suggest that molecules 7b and 9 exhibit offset packing models of (P-6,P-5)- and (M-6,M-5)-isomers. Optical resolution of the resultant compound 7b was finished, and their chiroptical properties, as well as the DFT calculations, were also examined.

Automated summary

Two novel double pi-extended [n]helicene (n = 5, 6) derivatives including pentagonal rings were synthesized and characterized, and their crystal structures revealed offset packing models. Optical resolution was performed on one compound, followed by the examination of their chiroptical properties and DFT calculations.