Development and validation of effective computational strategies for the study of metal nitroxide complexes

structures and spectromagnetic properties of some model copper nitroxide co mplexes were studied by both density functional and multireference post-Har tree-Fock models in order to assess the reliability of different computatio nal procedures. Next, the most promising density functional was employed fo r a systematic study of the effect of structural parameters and choice of t he model system on the magnetic properties of copper nitroxides. These resu lts provided the reference data for the extension of our recent nitroxide f orce field (J. Am. Chem. Sec. 1998, 120, 7069) to copper complexes. The res ulting computational tool (consisting of magnetic properties evaluated by d ensity functional methods possibly using geometries optimized by cheaper mo leculear mechanics approaches) seems particularly effective and well suited for systematic use also by nonspecialists. Extension to other metals is qu ite straightforward along the same lines.