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 χmT 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.

二价六氟乙酰丙酮合金属配合物[MII(hfac)2，其中M为Cu、Mn]与稳定硝酰基氮氧自由基（nitronyl nitroxide）配体2-(3-异丁基吡唑)-4,4,5,5-四甲基咪唑啉-1-氧基-3-氧化物（记为L）发生反应，得到两种一维锯齿链体系[{Cu(hfac)2}2L2]n与[CuMn(hfac)4L2]n。[{Cu(hfac)2}2L2]n单晶的固有特性为可随温度变化发生可逆结构重排，并伴随磁学异常。其摩尔磁化率与温度的乘积χmT在低温下表现出强反铁磁性，随温度升高则转变为铁磁性。而异核配合物[CuMn(hfac)4L2]n中，锰离子与硝酰基氮氧自由基之间存在反铁磁相互作用。