P-31 SOLID-STATE NMR-STUDIES OF CYCLIC AND ACYCLIC PHOSPHINE-METAL COMPLEXES - DETERMINATION OF CHEMICAL-SHIFT ANISOTROPY, SCALAR COUPLING 1JM-P (M = MN-55, MO-95,MO-97, W-183, AND MN-55 QUADRUPOLAR COUPLING-CONSTANTS

The P-31 chemical shift tensors of cyclic and acyclic metal phosphine complexes of the type [M]PPh2R ([M] = (OC)4BrMn (1), Cp(OC)2ClW (2), Cp(OC)2MeW (3); R = Et (a), Pr (b), Bu (c), Pe = Pentyl (d)) and [activated M]PPh2(CH2)n ([M] = (OC)4Mn (4), Cp(OC)2W (5), Cp(OC)2Mo (6); n = 3 (b), 4 (c); [M] = (OC)4MnSO2 (7); n = 2 (b), 3 (c), 4 (d)) are determined by solid-state NMR techniques and correlated to structural features of the compounds. In general the isotropic chemical shift in the solid-state was found to be of the same order as the chemical shift in solution. There are differences in the tensor components due to structural changes for the manganese complexes 1. Different bond weakening abilities of a ligand (trans influence) in complexes 2 and 3 cause a large change of only one tensor component, while the other components remain constant. A "crossover" of the center shielding tensor component and the low-field component is observed for the five- and six-membered rings 4b-7b and 4c-7c, respectively. Mn-55- and Mo-95/Mo-97-P-31 coupling constants have observed that are not obtainable in solution. The different spacings within the multiplets of the P-31 CP/MAS spectrum of the manganese complex Id allows us to estimate the quadrupolar coupling constant chi and the asymmetry parameter eta of the electric field gradient at manganese.