Wang Juan-Juan, Sun Juan, Yang Meng, Li Li-Cun
Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry and Tianjin Key Laboratory of Metal and Molecule-based Material Chemistry, Nankai University , Tianjin 300071, China.
Inorg Chem. 2015 Dec 7;54(23):11307-13. doi: 10.1021/acs.inorgchem.5b01915. Epub 2015 Nov 11.
New 2p-4f and 2p-3d-4f compounds [Tb(hfac)3(NIT-PhNO2)2]· 0.5C7H16 (1) and [Ln(hfac)3(NIT-PhNO2)2]2[Cu(hfac)2(NIT-PhNO2)2] (Ln(III) = Gd 2, Tb 3; hfac = hexafluoroacetylacetonate; NIT-PhNO2 = 2-(p-nitrophenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) have been obtained. Complex 1 consists of mononuclear trispin [Tb(hfac)3(NIT-PhNO2)2] units in which two radical ligands are ligated to the Tb(III) ion as monodentate ligands through the NO groups, while complexes 2 and 3 contain two kinds of trispin moieties, namely, [Ln(hfac)3(NIT-PhNO2)2] and [Cu(hfac)2(NIT-PhNO2)2]. In the [Cu(hfac)2(NIT-PhNO2)2] moiety, the radicals are bonded to the copper(II) ion in the axial positions via the nitroxides. For three compounds, 1D supramolecular chains are formed via the π-π stacking interactions involving the radical ligands. Magnetic investigations show that both Tb complexes exhibit slow relaxation of magnetization at low temperature; strikingly, complex 3 displays a higher energy barrier than that of 1. It represents the first example to use the paramagnetic complex to tune magnetic relaxation of 4f-based compounds.
新型2p - 4f和2p - 3d - 4f化合物[Tb(hfac)3(NIT - PhNO2)2]·0.5C7H16（1）和[Ln(hfac)3(NIT - PhNO2)2]2[Cu(hfac)2(NIT - PhNO2)2]（Ln(III)= Gd 2，Tb 3；hfac = 六氟乙酰丙酮；NIT - PhNO2 = 2 - (对硝基苯基)-4,4,5,5 - 四甲基咪唑啉 - 1 - 氧基 - 3 - 氧化物）已被合成。配合物1由单核三自旋[Tb(hfac)3(NIT - PhNO2)2]单元组成，其中两个自由基配体通过NO基团作为单齿配体与Tb(III)离子配位，而配合物2和3包含两种三自旋部分，即[Ln(hfac)3(NIT - PhNO2)2]和[Cu(hfac)2(NIT - PhNO2)2]。在[Cu(hfac)2(NIT - PhNO2)2]部分中，自由基通过氮氧化物在轴向位置与铜(II)离子键合。对于这三种化合物，通过涉及自由基配体的π - π堆积相互作用形成了一维超分子链。磁性研究表明，两种Tb配合物在低温下均表现出缓慢的磁化弛豫；引人注目的是，配合物3显示出比配合物1更高的能垒。它代表了使用顺磁性配合物调节基于4f化合物的磁弛豫的首个实例。
