Synthesis and properties of the copper(II) complexes with stable radical

Four novel copper(II) complexes have been synthesized, namely Cu(hfac)₂NITPhNO₂ (1), Cu(hfac)₂NITPhCH₃ (2), Cu(pfpr)₂NITPhNO₂, (3) and Cu(pfpr)₂NITPhCH₃ (4), where hfac=hexafluoro-acetylacetonate, pfpr=pentafluoropropionate, NITR=2-R-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxyl-3-oxide. (R=4-nitrophenyl, 4-methylphenyl). These complexes were characterized by elemental analyses, IR, electronic spectra and molar conductance. The temperature-dependent magnetic susceptibility of complexes 1 and 3 have been studied in the 4–300 K range, giving the exchange integral J=10.56 cm^−l for complex 1 and J=−30.9 cm^−l for complex 3.