Angewandte Chemie International Edition
Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Cover Picture (Angew. Chem. Int. Ed. Engl. 18/1994)
The cover picture shows a complex composed of 16 Pb2+ ions (in blue) and two 16-fold deprotonated γ-cyclodextrin tori (O atoms in red), in which each alkoxide O atom bridges two Pb atoms. An eight-point star of P2+ ions results; the diolate residues face each other, and the inner Pb2+ ions have 4 + 2 coordination. The complex is formed in the presence of a substoichiometric amount of Pb2+, which hints at a cooperative mechanism of formation. P. Klüfers and J. Schuhmacher report more on this attractive first member of a long-neglected class of compounds on p. 1863 ff.