Planar Chirality in 2,2-Diphenyl-1,3,6,9-tetraoxacycloundecane

The crystal of benzophenone crown ether acetal, C₁₉H₂₂O₄, with an 11-membered ring has two crystallographically independent molecules in the unit cell. The bond lengths and angles in the ring moiety are similar to those of analogous crown ethers. The 11-membered rings are greatly twisted to adopt planar-chiral structures and the unit cell contains two sets of enantiomers.

-1