Angewandte Chemie International Edition
Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Cover Picture (Angew. Chem. Int. Ed. Engl. 4/1988)
The cover shows part of a homonuclear two-dimensional NMR spectrum (E. COSY) of the cyclic hexapeptide cyclo(-Pro-Phe2-D-Pro-Phe2-), which exists in two slowly interconverting conformations in CDCl3. In order to show clearly the resolution now possible, a single cross peak is enlarged with a magnifying glass. These and similar spectra allow the spectroscopic parameters (e.g., coupling constants J and NOE effects) of even complex molecules to be determined with great accuracy and thus make it possible to elucidate the structures of molecules in solution. The article by H. Kessler, M. Gehrke, and C. Griesinger on page 490ff. describes how such spectra are recorded and discusses the various techniques available. The basic concepts required for their proper application and further development are dealt with in detail.