3,12-Dimethoxy-5,6,9,10-tetrahydro-[5]helicene-7,8-dicarbonitrile

Abstract

The complete molecule of the title compound, C26H20N2O2, is generated by a crystallographic twofold axis. The torsion angle between the terminal and central benzene rings is −32.5 (2)°. The torsion angle along the inner helical rim of the molecule is −18.8 (2)° with each other. The C...C distance between the terminal rings is 3.016 (2) Å. In the crystal, weak C—H...N hydrogen bonds are observed.

Crystal structure of 3,13-dimethoxy-5,6,10,11-tetrahydrofuro[3,4-i][5]helicene-7,9-dione

“…C24-O2-C12-C13 [À2.9 (4) ] vs C24B-O2B-C12B-C13B [À5.7 (4)] and C23-O1-C3-C2 [170.0 (2)] vs C23B-O1B-C3B-C2B [À176.9 (3)]. Moreover, unlike in another 3,12-dimethoxy[5]helicene derivative (Sahasithiwat et al, 2014) where both methoxy groups are bent inward, one of methoxy groups of the title compound is bent outward. In molecule A, this outward bending results from C23-H23AÁ Á ÁO3B(x À 1, y À 1, z) hydrogen bonding, while in molecule B, the bending is the result of steric hindrance between atoms C23B and C24B(Àx + 1, Ày + 1, Àz) of paired molecules (Fig.…”