A general protocol for the structural characterization of paramagnetic molecular solids usingsolid-state NMR is provided and illustrated by the characterization of a high-spin FeII catalyst precursor.We show how good NMR performance can be obtained on a molecular powder sample at natural abundanceby using very fast (>30 kHz) magic angle spinning (MAS), even though the individual NMR resonanceshave highly anisotropic shifts and very short relaxation times. The results include the optimization ofbroadband heteronuclear (proton-carbon) recoupling sequences for polarization transfer; the observationof single or multiple quantum correlation spectra between coupled spins as a tool for removing theinhomogeneous bulk magnetic susceptibility (BMS) broadening; and the combination of NMR experimentsand density functional theory calculations, to yield assignments.
