Heterospin complexes of fluorinated dinuclear CuII and MnII triketonates with nitroxides
作者:V. I. Ovcharenko、S. V. Fokin、G. V. Romanenko、A. S. Bogomyakov、D. S. Yachevskii、D. L. Chizhov、V. N. Charushin、O. N. Chupakhin
DOI:10.1007/s11172-010-0219-8
日期:2010.6
Dinuclear heterospin complexes of CuII and MnII 1,1,1,7,7,7-hexafluoroheptane-2,4,6-trionates ([Cu2L2] and [Mn2L2], respectively) with nitronyl nitroxides 2-R-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide 1-oxyls (NIT-R, R = H, Me, Et, m-C5H4N, m-NCC6H4, p-NCC6H4, PzMe) and the diradical NIT-Pz-(CH2)4-Pz-NIT (Pz is 1,4-pyrazolylene) were synthesized and structurally characterized. In the complexes under study, the CuII atom tends to have the square-pyramidal coordination environment, and the MnII atom is in an octahedral environment. The magnetochemical investigation of the compounds in the temperature range of 2–300 K showed that the antiferromagnetic exchange coupling dominates in the [Cu2L2] molecules, whereas this coupling in [Mn2L2] is manifested in the experimental plot μeff(T) at T < 100 K. The magnetic properties of the heterospin complexes of [Cu2L2] with NIT-R are also determined by the intramatrix antiferromagnetic exchange coupling. For the complexes of [Mn2L2] with NIT-R, the coordination mode of the nitroxide plays a decisive role.
CuII 和 MnII 1,1,1,7,7,7-六氟庚烷-2,4,6-三元酸酯(分别为 [Cu2L2] 和 [Mn2L2])与硝基硝基氧 2-R-4,4 的双核异旋配合物, 5,5-四甲基-4,5-二氢-1H-咪唑-3-氧化物1-氧基(NIT-R,R = H,Me,Et,m-C5H4N,m-NCC6H4,p-NCC6H4,PzMe)和合成了双自由基NIT-Pz-(CH2)4-Pz-NIT(Pz是1,4-亚吡唑基)并进行了结构表征。在所研究的配合物中,CuII原子倾向于具有方锥体配位环境,并且MnII原子处于八面体环境中。在 2–300 K 温度范围内对化合物的磁化学研究表明,反铁磁交换耦合在 [Cu2L2] 分子中占主导地位,而 [Mn2L2] 中的这种耦合在 T < 100 时的实验曲线 μeff(T) 中得到体现K. [Cu2L2] 与 NIT-R 的异旋复合物的磁性也由基质内反铁磁交换耦合决定。对于[Mn2L2]与NIT-R的配合物,硝基氧的配位方式起着决定性的作用。