Intrinsic and environmental effects in the physico-chemical properties of nitroxides. The case of 2-phenyl-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl 3-oxide

The geometry, conformational behaviour and magnetic properties of 2-phenyl-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl 3-oxide, an important spin carrier in molecular magnetic materials, have been studied by a combined experimental and theoretical approach. The available structural data have been completed by the electronic spin resonance spectrum in aqueous solution, and we have utilised a hybrid Hartree-Fock/Kohn-Sham method coupled to a polarizable continuum representation of the solvent. The computations show that the molecule has a non-planar conformation in the gas phase and in solution, but that the molecular magnetic properties are significantly tuned by environmental effects.