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由于歧化反应的存在,以前试图合成二环戊二烯基轻稀土氯化物一直没有成功。我们用NdCl_3·2C_4H_8O和环戊二烯钠(摩尔比为1:1.8)在四氢呋喃中在室温下反应,成功地得到[(η~5-C_5H_5)_2NdCl·OC_4H_8]_2配合物单晶。元素分析、红外光谱和X光电子能谱的数据证实了这一配合物的组成。在—60℃的干燥氮气保护下,收集X光衍射数据,测定了晶体结构,晶体属单斜晶系空间群为P2_1/c,z=2。晶格参数为:a=8.201(3),b=21.589(6),c=8.596(3),β=109.10(3)~0晶体结构是利用Patterson与Fourier技术得到,对1680个反射,经最小二乘修正,最后的R=0.0636。结构表明,该配合物是以两个氯离子桥联的二聚体的方式存在。四氢呋喃分子中的氧原子同金属离子键合,Nd=O键长为2.55,两个环戊二烯分子中的所有碳原子同金属离子间的平均的Nd—C键长为2.76A,Nd—Cl=2.79,Nd—Cl_a=2.86,Nd—Nd_a=4.52,Cl—Nd—Cl_a键角为73.7°。晶体结构分析排除了该配合物是(η~5-C_5H_5)_3Nd与NdCl_3的混合物的可能性。
Previous attempts to synthesize dicyclopentadienyl light rare earth chlorides have been unsuccessful due to the disproportionation reaction. We use NdCl_3 · 2C_4H_8O and sodium cyclopentadienyl (molar ratio of 1: 1.8) in tetrahydrofuran at room temperature, successfully obtained [(η ~ 5-C_5H_5) _2NdCl · OC_4H_8] _2 complex single crystal. The data of elemental analysis, infrared spectroscopy and X-ray photoelectron spectroscopy confirmed the composition of this complex. Under the protection of -60 ℃ dry nitrogen, the X-ray diffraction data were collected and the crystal structure was determined. The crystal belongs to the monoclinic space group P2_1 / c, z = 2. The lattice parameters are: a = 8.201 (3), b = 21.589 (6), c = 8.596 (3), β = 109.10 (3) ~ 0 The crystal structure is obtained using Patterson and Fourier techniques. For 1680 reflections, Least squares correction, the last R = 0.0636. The structure shows that the complex exists as a dimer of two chloride ions. The oxygen atom in the tetrahydrofuran molecule is bonded to the metal ion with the Nd = O bond length of 2.55. The average Nd-C bond length between all the carbon atoms in the two cyclopentadiene molecules and the metal ion is 2.76A. The Nd- Cl = 2.79, Nd-Cl_a = 2.86, Nd-Nd_a = 4.52, Cl-Nd-Cl_a bond angle of 73.7 °. Crystal structure analysis ruled out the possibility of this complex being a mixture of (η ~ 5-C_5H_5) _3Nd and NdCl_3.