Synthesis and properties of the complexes of lanthanides with nitronyl nitroxide biradical

Five novel complexes of formula [Ln(hfac)₃] · BNPhOM, where La = Gd, Ho, Dy, Y, Er; Mac = hexfluoracetylacetonate; BNPhOM=1,3-[bis-2,2′,-(4,4,5,5-tetramethyl-4,5-di-hydro-1H-imidazolyl-1-oxyl-3-oxide) phenoxy] propane, have been prepared and characterized by elemental analysis, molar conductances, IR and electronic spectra. The temperature dependence of the magnetic susceptibility for Gd(III) and radical was measured (2—-300 K). The observed data were successfully simulated giving the exchange integral J = 0.28 cm⁻¹, J' = - 0.33 cm⁻¹. These results indicate a weak ferromagnetic spin exchange interaction between Gd(III) ion and the radical and a weak antiferromagnetic spin exchange interaction between the radical and radical.