Crystal structures and magnetic properties of Cu(II) complexes with pyrazole-substituted iminonitroxyl radicals: New trinuclear heterospin complexes

The paper describes the crystal structures and magnetic properties of complexes of copper(II) hexafluoroacetate (Cu(hfaC)(2)) with stable pyrazole-substituted iminonitroxyl radicals containing the pyrazole substitutuent in the second position, of the 2-imidazoline cycle (L). A new group of [Cu(hfac)(2)](3)(L)(2) complexes is found, in. which L performs a bidentate-bridge function due to the coordination of the imine N atoms of the pyrazole and imidazoline cycles. It is shown that in. the solid complexes there are Cu2+-N=C-N-O exchange routes with high-energy ferromagnetic interactions (similar to60-100 cm(-1)).