MULTINUCLEAR NMR-STUDY OF HFECO3(CO)(9)[P(OCH3)(3)](3) IN THE SOLID-STATE AND IN SOLUTION

P-31 and Co-59 NMR have been applied to study the structure and dynami cs of the tetrahedral mixed-metal cluster HFeCO3(CO)(9)[P(OCH3)(3)](3) both in the solid state and in solution. The P-31 chemical shift (CS) anisotropy, the direct (D) and indirect (J) dipolar P-31-Co-59 intera ctions, and the relative orientation of the CS, D, and J tensors have been determined by iterative fitting of the P-31 MAS NMR spectra at tw o magnetic field strengths (4.7 and 7.1 T). The quadrupole coupling co nstant as well as the isotropic part and anisotropy of the CS tensor a t the Co-59 nucleus has been evaluated by a moment analysis of the sol id-state central transition line shape. The P-31 and Co-59 NMR data, w hich are both influenced by second-order quadrupolar shifts, clearly s how a departure from the C-3 upsilon molecular symmetry due to a solid -state packing effect. Using the static interaction parameters obtaine d by solid-state NMR, it was possible to evaluate the overall rate of molecular motion in solution from Co-59 relaxation measurements. The a nalysis of the solution-state P-31 NMR saddle-shaped spectrum gives th e same (1)J(P-31-Co-59) coupling constant as in the solid state. Moreo ver, no Q-CS relaxation interference effects are detected in agreement with the very weak contribution of the CS anisotropy to the Co-59 rel axation predicted by the solid-state NMR data.