Two copper(II)-nitronyl nitroxide radical dimers with a bulky β-diketonate: Synthesis, structure and magnetic behavior

► Crystal structure of two pyridyl nitronyl substituted nitroxide copper(II) complexes. ► Bulky groups in the β-diketonate ligand ► Two coordination modes of the pyridyl substituted nitronyl nitroxide radical to copper(II) ion. ► Antiferro- and ferromagnetic interactions between copper(II) and organic radical