LI-7 SOLID-STATE NMR SPECTROSCOPIC STUDY OF CYCLOPENTADIENYLLITHIUM COMPLEXES

Eighteen cyclopentadienyllithium complexes were studied by solid-state Li-7 NMR spectroscopy. It is shown that the chemical shift gives info rmation on the type of complex, i.e. whether the complex is a contact ion pair, a solvent-separated ion pair, a sandwich structure or a poly meric material. These shift differences are due to the ring current of the aromatic anion. In order to obtain information about the solvatio n of the lithium cation, the quadrupolar coupling constant chi has to be determined. The chi value depends on the number and type of donor a toms in the ligand, where the nitrogen-containing ligands give rise to higher chi values than the oxygen analogues. (C) 1998 John Wiley & So ns, Ltd.