Paramagnetic Susceptibility by NMR: The "Solvent Correction" Removed for Large Paramagnetic Molecules

For large paramagnetic molecules in solution, the paramagnetic and diamagnetic contributions to the magnetic susceptibility are comparable and may be determined by NMR (Evans' method) in the same conditions (concentration, temperature, solvent). Theoretical considerations show that the solvent correction similarly affects both measurements and cancels in the combined equations calculating the magnetic susceptibilities and the magnetic moments. These simplified equations have been successfully applied for the determination of the magnetism of self-assembled heterodinuclear 3d-4f supramolecular complexes in acetonitrile.