6533b857fe1ef96bd12b4560

RESEARCH PRODUCT

Two strained hexahelicenophanes

Herbert MeierDieter SchollmeyerManfred Schwertel

subject

Steric effectsCrystallographychemistry.chemical_compoundHeliceneChemistryStereochemistryCrystal structureGeneral MedicineGround stateRing (chemistry)BenzeneRacemizationGeneral Biochemistry Genetics and Molecular Biology

description

The crystal structures of the [6]­helicenes 4,13-(1,10-deca­methyl­ene­dioxy)­hexahelicene, C36H34O2, (I), and 4,13-(1,8-octa­methyl­ene­dioxy)­hexahelicene, C34H30O2, (II), show strong steric interactions between the terminal benzene rings and the poly­methyl­ene­dioxy chains. The shortest ring A and F distances amount to 2.941 (3) and 2.902 (3) A, respectively. The increased steric energy of the ground state is responsible for a significantly lower racemization barrier of (I) and (II) in comparison to the unsubstituted [6]­helicene.

yearjournalcountryeditionlanguage
2000-06-01Acta Crystallographica Section C Crystal Structure Communications
https://doi.org/10.1107/s0108768100003141