Angewandte Chemie International Edition
Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Cover Picture (Angew. Chem. Int. Ed. Engl. 4/1985)
The cover page shows schematically the main area of research of the Max-Planck-Institut für Kohlenforschung in Mülheim: the synthesis and structure elucidation of organometallic compounds and the study of their catalytic activity. The activity and selectivity of (η5-RC5H4)Co(cod) catalysts in the synthesis of pyridine is controlled by the R residue. If R is a donor, the 59Co-NMR signals are shifted upfield and the catalytic activity decreases; the R-C bond is orthogonal to the schematically drawn double bonds of the COD ligand (structure and measured points on right side). If R is an acceptor, Co is deshielded and the catalytic activity increases; the R-C bond is parallel to the COD double bonds (structure and measured points on left side). Further details on the structure-activity relationships for cobalt complexes in homogeneous catalysis are reported by H. Bönnemann in a review on p. 248.