Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry College of Chemistry, Nankai University, Tianjin 300071, China.
Dalton Trans. 2018 Oct 23;47(41):14630-14635. doi: 10.1039/c8dt03222j.
A multi-dentate nitronyl nitroxide radical Nit-Ph-3,5-bIm (Nit-Ph-3,5-bIm = 2-[3,5-bis(1-imidazole)-phenyl]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) reacted with Co(hfac)2·2H2O or Cu(hfac)2 to yield two novel 3d-radical complexes {[Co(hfac)2]2(Nit-Ph-3,5-bIm)}n1 and {[Cu(hfac)2]7(Nit-Ph-3,5-bIm)3}n2 (hfac- = hexafluoroacetylacetonate). In both compounds, the Nit-Ph-3,5-bIm radical ligand behaves as a tetradentate ligand to link four M(hfac)2 units in a μ4-η1:η1:η1:η1-coordination mode via its two NO groups and two N atoms of imidazole, generating a unique loop chain for 1 and a three-dimensional framework for 2. The magnetic studies revealed a strong antiferromagnetic Co-ON exchange interaction in 1 while a ferromagnetic Cu-ON interaction is observed in 2. The dc magnetic behaviors of two complexes are analyzed by means of appropriate magnetic models. Furthermore, ac magnetic susceptibilities of the Co complex reveal slow relaxation of magnetization.
多齿硝酰基氮自由基 Nit-Ph-3,5-bIm（Nit-Ph-3,5-bIm = 2-[3,5-双（1-咪唑基）-苯基]-4,4,5,5-四甲基咪唑啉-1-氧-3-氧化物）与 Co(hfac)2·2H2O 或 Cu(hfac)2 反应，生成两个新型 3d-自由基配合物 {[Co(hfac)2]2(Nit-Ph-3,5-bIm)}n1 和 {[Cu(hfac)2]7(Nit-Ph-3,5-bIm)3}n2（hfac- = 六氟乙酰丙酮酸盐）。在这两个化合物中，Nit-Ph-3,5-bIm 自由基配体表现为四齿配体，通过其两个 NO 基团和咪唑的两个 N 原子，以 μ4-η1:η1:η1:η1-配位方式连接四个 M(hfac)2 单元，分别生成 1 的独特环链和 2 的三维框架。磁性研究表明，在 1 中存在强烈的反铁磁 Co-ON 交换相互作用，而在 2 中观察到铁磁 Cu-ON 相互作用。通过适当的磁性模型分析了两个配合物的直流磁行为。此外，Co 配合物的交流磁化率显示出缓慢的磁化弛豫。
