Cu-Ln compounds based on nitronyl nitroxide radicals: synthesis, structure, and magnetic and fluorescence properties
Cu-Ln compounds based on nitronyl nitroxide radicals: synthesis, structure, and magnetic and fluorescence properties
复制标题
基于硝基硝基氧自由基的 Cu-Ln 化合物：合成、结构以及磁性和荧光性质
作者：
Meng Yang;Juan Sun;Jianni Guo;Guifang Sun;李立存
三个系列硝基氮氧化物自由基3 - 4f化合物，即[Ln(hfac)3Cu(hfac)2NIT-5Br-3Py]n (LnIII = La (1), Pr (2)), [Ln(hfac)3Cu(hfac)2NIT-5Br-3Py] (LnIII = Gd (3), Tb （4), Dy(5)）和[Ln(hfac)3Cu(hfac)2(NIT-5Br-3Py)2]n (LnIII = Gd (6), Tb (7), Dy (8))；ni - 5br - 3py = 2-（5-溴-3-吡啶基）-4,4,5,5-四甲基咪唑-1-氧基-3-氧化物；Hfac =六氟乙酰丙酮)已成功制备。单晶x射线晶体学分析表明，配合物1和2由自由基配体通过NO基团桥接Ln(hfac)3单元组成的一维链组成，附加的Cu离子与自由基的氮原子配位。配合物3-5是由硝基氮氧化物自由基桥接的稀有杂双核Cu-Ln化合物，而配合物6-8具有重复序列的一维链结构[Cu-Rad-Ln-Rad]。直流电磁学研究表明，化合物3 ~ 8中的LnIII离子与配位NO基团之间存在铁磁相互作用。Tb-Cu衍生物（配合物4和7）显示频率相关的交流磁化率，表明慢磁弛豫行为。配合物4和7的室温光致发光光谱在可见光区表现出强烈的特征发射。
Three series of nitronyl nitroxide radical 3d–4f compounds, namely, [Ln(hfac)3Cu(hfac)2NIT-5Br-3Py]n (LnIII = La (1), Pr (2)), [Ln(hfac)3Cu(hfac)2NIT-5Br-3Py] (LnIII = Gd (3), Tb (4), Dy (5)) and [Ln(hfac)3Cu(hfac)2(NIT-5Br-3Py)2]n (LnIII = Gd (6), Tb (7), Dy (8); NIT-5Br-3Py = 2-(5-bromo-3-pyridyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide; hfac = hexafluoroacetylacetonate) have been successfully obtained. Single crystal X-ray crystallographic analysis reveals that complexes 1 and 2 consist of 1D chains built up by Ln(hfac)3 units bridged by the radical ligands through their NO moieties and the additional Cu ions are coordinated to the nitrogen atoms of the radicals. Complexes 3–5 are rare hetero-binuclear Cu–Ln compounds bridged by the nitronyl nitroxide radicals while complexes 6–8 possess one-dimensional chain structures with a repeating [Cu–Rad–Ln–Rad] sequence. DC magnetic studies show ferromagnetic interaction between the LnIII ion and the coordinated NO group in compounds 3–8. Tb–Cu derivatives (complexes 4 and 7) display frequency dependent ac magnetic susceptibilities, indicating slow magnetic relaxation behavior. The room-temperature photoluminescence spectra of complexes 4 and 7 exhibit strong characteristic emissions in the visible region.