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Cover Picture (Angew. Chem. Int. Ed. Engl. 3/1993)
Publication year - 1993
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Reports
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.199303131
Subject(s) - annulene , cover (algebra) , antiaromaticity , crystallography , combinatorics , planar , ring (chemistry) , chemistry , physics , stereochemistry , computer science , mathematics , computer graphics (images) , molecule , aromaticity , organic chemistry , engineering , mechanical engineering
The cover picture shows the space‐filling model of a tetraethynyltetrahydro[12] annulene protected fourfold by Si( i Pr 3 ) 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 C 60 . 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 C 60 boom a topical field of research.