Synthesis, crystal structures and magnetic properties of coordination compounds with nitronyl nitroxide radicals and [m(hfac)2] (m = cuii and mnii)

The reaction of metal hexafluoroacetylacetonato [MII(hfac)2, M = Cu, Mn] with the stable nitronyl nitroxide 2-(3-isobutyl- pyrazole)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (L), resulted in one dimensional zig-zag chain systems [{Cu(hfac)2}2L2]n and [CuMn(hfac)4L2]n. The main feature inherent in the nature of [{Cu(hfac)2}2L2]n single crystals is their ability to undergo reversible structural rearrangements with temperature variation, accompanied by anomalies of magnetism. The value of cmT shown strongly antiferromagnetic at low temperature and becomes ferromagnetic when the temperature increases. And the heteronuclear complex [CuMn(hfac)4L2]n shows antiferromagnetic interactions between manganese and nitronyl nitroxide.