Cyclobishelicenes: shape-persistent figure-eight aromatic molecules with promising chiroptical properties

Antoine Robert (1) , Guillaume Naulet (1) , Harald Bock (1) , Nicolas Vanthuyne (2) , Marion Jean (2) , Michel Giorgi (3) , Yannick Carissan (2) , Christie Aroulanda (4) , Antoine Scalabre (5) , Emilie Pouget (5) , Fabien Durola (1) , Yoann Coquerel (2)

1 CRPP - Centre de Recherche Paul Pascal
2 ISM2 - Institut des Sciences Moléculaires de Marseille
3 FSCM - Fédération Sciences Chimiques Marseille
4 ICMMO - Institut de Chimie Moléculaire et des Matériaux d'Orsay
5 CBMN - Chimie et Biologie des Membranes et des Nanoobjets

Cyclobis[n]helicenes (n = 3 or 5) are chiral D2-symmetric p-conjugated macrocycles with stable lemniscular, or figure-eight, shapes. The conformational analysis of five different cyclobis[n]helicenes revealed that these molecules can only exist as their lemniscular conformers with high barriers to enantiomerization (>200 kJ.mol-1). The enantiomers of a cyclobis[5]helicene were resolved by HPLC and their unusual chiroptical properties were attributed to the inherent chirality of their macrocyclic figure-eight.

Keywords: helical structures; conformation analysis; aromatic compounds; chirality; chiroptical properties

Domains: Chemical Sciences; Theoretical and/or physical chemistry; Chemical Sciences; Material chemistry

Antoine Robert, Guillaume Naulet, Harald Bock, Nicolas Vanthuyne, Marion Jean, et al.. Cyclobishelicenes: shape-persistent figure-eight aromatic molecules with promising chiroptical properties. Chemistry - A European Journal, 2019, 25 (63), pp.14364-14369. ⟨10.1002/chem.201902637⟩. ⟨hal-02265747⟩