Structural elucidation of bipyridine helicate complexes and their precursors by NMR spectroscopy

H-1 and C-13 NMR assignments of bipyridine helicate complexes and their precursor ligands were achieved using gradient-based homo- and hetero-correlated 2D experiments. The observed trends in H-1 and C-13 chemical shift variations [Delta delta (H) and Delta delta (C)], on passing from the ligands to the complexes, are accounted for on the basis of MO evaluation of atomic charges. Copyright (C) 2001 John Wiley & Sons, Ltd.