Angewandte Chemie International Edition

Cover image for Vol. 55 Issue 44

Editor: Peter Gölitz, Deputy Editors: Neville Compton, Haymo Ross

Online ISSN: 1521-3773

Associated Title(s): Angewandte Chemie, Chemistry - A European Journal, Chemistry – An Asian Journal, ChemistryOpen, ChemPlusChem, Zeitschrift für Chemie

Cover Picture (Angew. Chem. Int. Ed. Engl. 3/1993)

32_03/1993The cover picture shows the space-filling model of a tetraethynyltetrahydro[12] annulene protected fourfold by Si(iPr3)3. Its core is a planar framework of 20 carbon atoms, as the superimposed structural formula clearly indicates. This representation is based on the X-ray crystallographic data of the compound, which is astonishingly stable despite the considerable strain of the central twelve-membered ring. Its electronic absorption spectrum indicates the presence of an antiaromatic [4n] π-electron perimeter, and its purple solutions look remarkably similar to the solutions of C60. More about this compound as well as the analogously constructed [18]annulene, a very promising starting material for new planar hydrocarbon networks, are reported by F. Diederich et al. on pages 406 ff. Also A. de Meijere et al. show with their synthesis of the perspirocyclopropanated [3]rotane (p. 401 ff) a route to new carbon modifications—since the C60 boom a topical field of research.

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