Synthesis, structural and magnetic characterization of a new copper(II)-nitronyl nitroxide radical complex

In this work we describe the structure and the magnetic properties of a new copper(II)-NIT complex, where NIT stands for nitronyl nitroxide radical. This was achieved using (NBu4)(4)[Cu-2(bopba)] as a precursor (where NBu4+ is the tetrabutyl ammonium cation and bopba is bis-o-phenylenebis(oxamate)), whose crystal structure was resolved and its magnetics properties studied. From the reaction of this precursor with a cationic nitronyl nitroxide radical, a new compound was prepared and magnetically characterized, namely (pEtRad)(4)[Cu-2(bopba)] (where pEtRad(+) stands for the cationic para-2-(4-pyridil)-4,4,5,5-tetramethylimidazoline-loxyl-3-oxide radical). The magnetic properties suggest that in this six-spin complex there is a competition between short range ferromagnetic and antiferromagnetic interactions. The ferromagnetic interaction can be explained by the orthogonality of the involved magnetic orbitals.