SYNTHESIS, CRYSTAL STRUCTURES AND MAGNETIC PROPERTIES OF COORDINATION COMPOUNDS WITH NITRONYL NITROXIDE RADICALS AND [M(HFAC)₂] (M = CU^II AND MN^II)

The reaction of metal hexafluoroacetylacetonato [M^II(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 χ_mT 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.

Keywords:
nitronyl nitroxide; M^II(hfac)₂ complexes; X-ray crystal structure; spin-crossover-like; magnetic property.