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本文用LnCl_3(Ln=La,Pr,Nd)同环戊二烯钠在THF溶液中反应,制备出(η~5-C_5H_5)_3Ln·OC_4H_8化合物单晶.采用低温技术,在—60℃的干燥氮气保护下,收集(η~5-C_5H_5)_3HPr·OC_4H_8[(η~5-C_5H_5)Nd·OC_4H_8]的单晶X射线衍射数据,解出了晶体结构.它们同属单斜晶系,P2_1/n 空间群.结构表明,THF分子中的氧原子与金属离子键合,Pr—O键长为2.56(1)A,Nd—O键长为2.54(1)A.三个环戊二烯分子中的所有碳原子与金属离子的间距,均在成键范围,其平均键距Pr—C为2.80(2)A,Nd—C为2.78(2)A.它们同已报道的(η~5-C_5H_5Ln·OC_4H_8(Ln=Y,La,Gd)结构一起,可很好地解释镧系收缩理论,同时为研究稀土元素的价态和键,提供了有用的结构信息。
In this paper, a single crystal of (η ~ 5-C_5H_5) _3Ln · OC_4H_8 was prepared by reaction of LnCl_3 (Ln = La, Pr, Nd) with sodium cyclopentadienide in THF solution. Single crystal X-ray diffraction data of (η ~ 5-C_5H_5) _3HPr · OC_4H_8 [(η ~ 5-C_5H_5) Nd · OC_4H_8] were collected under nitrogen gas to obtain the crystal structure. They belong to monoclinic system, n space group.The structure shows that the oxygen atom in the THF molecule is bound to the metal ion with a Pr-O bond length of 2.56 (1) A and a Nd-O bond length of 2.54 (1) A. Three cyclopentadiene molecules All the carbon atoms and metal ions in the bonding range, the average bond pitch Pr-C is 2.80 (2) A, Nd-C is 2.78 (2) A. They have been reported (η ~ 5 C_5H_5Ln · OC_4H_8 (Ln = Y, La, Gd) structure can well explain the theory of lanthanide shrinkage and provide useful structural information for the study of valences and bonds of rare earth elements.