Intrinsic and environmental effects in the structure and magnetic properties of organic molecular magnets: Bis(imino)nitroxide

The structure, conformational behavior, and magnetic coupling constant of a prototypical organic molecular magnet (the bis(imino)nitroxide) have been investigated in vacuo and in solution, combining a recent density functional theory/Hartree-Fock model with a refined,continuum description of the solvent. Comparison with previous sophisticated computations for a simplified model shows that our approach provides reliable magnetic couplings for a wide range (0-2000 cm(-1)) of interactions between the radical subunits. The computations performed for the true compound at the experimental conformation show that structural;and magnetic parameters are in remarkable agreement with experiment. Solvent effects are negligible concerning the magnetic coupling but modify the conformational behavior leading to an inter-ring torsional angle in better agreement with the experimental value.