Theoretical calculations of effective exchange integrals between nitronyl nitroxides with donor and acceptor groups

Abstract

Semi-empirical calculations on the basis of an extended McConnell model have been carried out for dimers of phenyl nitronyl nitroxides with donor or acceptor groups. The intermolecular effective exchange integrals are positive (ferromagnetic) for appropriately stacked forms of these species because of large spin polarization effects. Implications of these results are discussed in relation to the organic ferromagnetism discovered recently for para-nitrophenyl nitronyl nitroxide.