论文部分内容阅读
用无水硝酸铈铵[(NH_4)_2Ce(NO_3)_6]与环戊二烯钠(C_5H_5Na)在四氢呋喃中按1:6摩尔比反应,得到(η~5-C_6H_5)_3Ce·OC_4H_8;用ErCl_3·nTHF与环辛二烯钾(C_8H_(11)K)按等摩尔比于-78℃反应,升至室温,再按1:2摩尔比加入C_5H_5Na,得到了(η~5-C_5H_5)_3Er·OC_4H_8.两配合物晶体结构测定结果表明都属单斜晶系P2_(1/n)空间群.Ce配合物与已测定过的(η~5-C_5H_5)_3Ln·OC_4H_8(Ln=La,PrNd,Gd,Dy,Y,Lu)的晶体结构不是同构物:而Er配合物则是同构物.Ce配合物中的Ce—O、Ce—Cent(环戊二烯环中心)和平均Ce—C(η~5)键长不符合镧系收缩规律,而Er配合物的键长符合.这说明在(η~5-C_5H_5)_3Ln·OC_4H_8同构系列中在Ce和Dy有两个断点,但不存在所谓的“钆断现象”,因为Y,Er,Lu配合物的Ln—O和Ln—C(η~5)和Ln—Centroid距离不大于Gd的相应值.
(Η ~ 5-C_6H_5) _3Ce · OC_4H_8 with anhydrous ammonium cerium nitrate [(NH_4) _2Ce (NO_3) _6] and sodium cyclopentadienide (C_5H_5Na) in tetrahydrofuran at a molar ratio of 1: 6. · NTHF and cyclooctadiene potassium (C_8H_ (11) K) were reacted at -78 ℃ in equimolar ratio and allowed to rise to room temperature. Then C_5H_5Na was added in a molar ratio of 1: 2 to obtain (η~5-C_5H_5) _3Er · OC_4H_8.The crystal structures of the two complexes show that they belong to the monoclinic P2_ (1 / n) space group. The Ce complexes have the similarities with the previously reported (η_5-C_5H_5) _3Ln · OC_4H_8 (Ln = La, PrNd, The crystal structure of Gd, Dy, Y, Lu) is not isomorphism: Er complexes are isomers. Ce-O, Ce-Cent and Ce- The bond length of C (η ~ 5) does not accord with the law of lanthanoid shrinkage, and the bond length of Er complex is consistent, which shows that there are two breakpoints in Ce and Dy in the (η ~ 5-C_5H_5) _3Ln · OC_4H_8 isomorphism series , But there is no so-called “gadolinium breakage phenomenon” because the Ln-O and Ln-C (n-5) and Ln-Centroid distances of the Y, Er, Lu complexes are not greater than the corresponding values of Gd.