Angewandte Chemie International Edition

Cover image for Vol. 54 Issue 17

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. 3/1992)

31_03/1992The cover picture shows the aesthetically pleasing structure of the highly symmetrical dianion [(μ5-In){Mn(CO)4}5]2−. Five manganese atoms (red) form a five-membered ring, which is slightly distorted from planarity towards an envelope configuration. Each manganese atom is approximately octahedrally surrounded by two axial and two equatorial carbonyl groups (C atoms green, O atoms blue), and two neighboring manganese atoms. In the middle of these cyclo-[Mn5(CO)20] “ligands”, like a spider in its web, lies an indium atom, which forms bonding interactions with every Mn atom. This pentagonal-planar coordination usually has a substantially less favorable energy than the trigonal-bipyramidal or square-pyramidal coordination. Till now it has only been observed when it could be interpreted as a pseudo-pentagonal-bipyramid. M. Schollenberger, B. Nuber, and M. L. Ziegler report this unusual coordination compound on p. 350ff. No less exciting is the structure of [Ni(PtBu)6], which contains a Ni atom in a hexagonal-planar environment, reported by R. Ahlrichs, D. Fenske, H. Oesen, and U. Schneider on p. 323ff.

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