CMPO-calix[4]arenes with spacer containing intramolecular hydrogen bonding: Effect of local rigidification on solvent extraction toward f-block elements

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• 作者：Hongzhu Chu ; Lutao He ; Qian Jiang ; Yuyu Fang ; Yiming Jia ; Xiangyang Yuan ; Shuliang Zou ; Xianghui Li ; Wen Feng ; Yuanyou Yang ; Ning Liu ; Shunzhong Luo ; Yanqiu Yang ; Liang Yang ; Lihua Yuan
• 关键词：CMPO-calixarene ; Hydrogen bonding ; Solvent extraction ; f-Block elements
• 刊名：Journal of Hazardous Materials
• 出版年：15 January, 2014
• 年：2014
• 卷：264
• 期：Complete
• 页码：211-218
• 全文大小：1316 K

文摘

To understand intramolecular hydrogen bonding in effecting liquid-liquid extraction behavior of CMPO-calixarenes, three CMPO-modified calix[4]arenes (CMPO-CA) 5a-5c with hydrogen-bonded spacer were designed and synthesized. The impact of spacer rotation that is hindered by introduction of intramolecular hydrogen bonding upon extraction of La³⁺, Eu³⁺, Yb³⁺, Th⁴⁺, and UO₂²⁺ has been examined. The results show that 5b and 5c containing only one hydrogen bond with a less hindered rotation spacer extract La³⁺ more efficiently than 5a containing two hydrogen bonds with a more hindered rotation spacer, demonstrating the importance of local rigidification of spacer in the design of extractants in influencing the coordination environment. The large difference in extractability between La³⁺ and Yb³⁺ (or Eu³⁺) by 5b (or 5c), and the small difference by 5a, suggests intramolecular hydrogen bonding do exert pronounced influence upon selective extraction of light and heavy lanthanides. Log-log plot analysis indicates a 1:1, 2:1 and 1:1 stoichiometry (ligand/metal) for the extracted complex formed between 5b and La³⁺, Th⁴⁺, UO₂²⁺, respectively. Additionally, their corresponding acyclic analogs 7a-7c exhibit negligible extraction toward these metal ions. These results reveal the possibility of selective extraction via tuning local chelating surroundings of CMPO-CA by aid of intramolecular hydrogen bonding.