Angewandte Chemie International Edition
Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Cover Picture (Angew. Chem. Int. Ed. Engl. 9/1988)
The cover picture shows the molecular structure of centrohexaindan. The fascination of this topologically nonplanar molecule lies in the annelation of six cyclopentane rings around a central C-atom common to all rings. The central neopentane skeleton is bridged by six o-phenylene groups corresponding to the six edges of a regular tetrahedron, so that the central quaternary C-atom is surrounded by four further, equivalent quaternary C-atoms and should display ideal tetrahedral coordination. The molecule as a whole should have perfect Td symmetry in the ground state. It contains three fused 2,2'-spirobiindans, tribenzotriquinacene and triptindan (sym-tribenzo[3.3.3]propellane) are fourfold degeneratively condensed with each other, and finally the molecule also contains three fenestranes (tetrabenzo[188.8.131.52]fenestranes). Further details of this readily synthesizable compound are reported by D. Kuck et al, on page 1192.