NMR correlation experiments. Basic principles and progress

The arsenal of NMR methods for structure elucidations in all branches of chemistry has enormously increased in recent years and in particular two-dimensional techniques have opened up new areas for applications. Among the most widely used 2D experiments, homo-and hetero-nuclear shift correlations certainly have a leading position. Aside from the COSY experiment, one-and two-dimensional TOCSY spectroscopy has become popular and recent developments in this area will be discussed. In addition, the potential of the 2D INADEQUATE experiments is investigated and examples from analytical as well as structural studies are presented. Finally, the powerful heteronuclear shift correlation experiments and the advances achieved with gradient-enhanced techniques are discussed and demonstrated with various applications. (author)