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化学学报
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化学学报 ›› 2000, Vol. 58 ›› Issue (12): 1481-1492.    下一篇

研究论文

镧系元素配位化学新领域: 生理及更高pH下镧 系元素-羟基自组装多核配合物 研究

王瑞瑶;金天柱;郑智平   

  1. Department of Chemistry, The University of Arizona,;Tucson, Arizona 85721;北京大学化学与分子工程学院;北京大学稀土材料化学与应用国家重点实 验室
  • 发布日期:2000-12-15

A new paradigmatic lanthanide coordination chemistry: Assembling lanthanide-hydroxo clusters under physiological or higher-pH conditions

Wang Ruiyao;Jin Tianzhu;Zheng Zhiping   

  • Published:2000-12-15

PDF

476

被引次数

30

在生理及更高pH下以α-氨基酸或EDTA作为配体，抑制Ln(Ⅲ)水解得到了一类镧系元素-羟基自组装多核配合物。该类多核配合物以具有类立方烷结构的[Ln4(μ~3-OH)~4]^8^+为基本结构单元，可以单体{[Ln~4(μ~3-OH)~4]^8^+}，共顶点的“环状四聚体”{[Ln~1~2(μ~3-OH)~1~6]^2^0^+}或“环状五聚体”{[Ln~1~5(μ~3-OH)~2~0]^2^5^+}的形式稳定存在。本文报道了该类配合物的合成、结构及性质，探讨了卤素离子对“环状四聚体”及“环状五聚体”形成的模板效应，并初步证明了类立方烷结构单体，“环状四聚体”及“环状五聚体”乃是生理及更高pH下镧系元素的稳定存在形式。同时还证明了直接水解镧系元素硝酸盐或高氯酸盐能得到一类以正八面体结构的[Ln~6(μ~6-O)(μ~3-OH)~8]^8^+]为骨架的多核配合物。磁性测定表明，室温下各配合物的类立方烷结构中的镧系离子间无明显磁交换。

关键词: 镧系元素化合物, 络合物, 氨基酸, 模板效应, 水解, 立方烷

High-nuclearity lanthaide-hydroxo complexes were prepared via limited hydrolysis of lanthanides using α-amino acids or EDTA as supporting ligands. These novel substances, synthesized under physiological or even higher-pH conditions, exist as tetranuclear cuboid [Ln~4(μ~3-OH)~4]^8^+ core-containing clusters. With appropriate halide templates, "whell-like" supramolecular structures composed of four or five vertex-sharing [Ln~4(μ~3-OH)~4]^8^+ units are formed. The face-capped octahedral [Ln~6(μ~6-O)(μ~3-OH)~8]^8^+] cluster centering on an interstitial μ~6-O ligand is another stable form of lanthanide-hydroxo complexes and can be self-assembled via direct hydrolysis of lanthanide nitrates and perchlorates. The significant influence of pH conditions on lanthanide coordination chemistry is further illustrated by a new paradigmatic lanthanide- EDTA chemistry, wherein unprecedented multinuclear Ln-EDTA cluster complexes are realized.

Key words: LANTHANIDE SERIES COMPOUNDS, COMPLEX COMPOUNDS, AMINO ACID, MARTIX EFFECTS, HYDROLYSIS, CUBANE

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