Hydroxyquinoline-Calix[4]arene Conjugates as Ligands for Polynuclear Lanthanide Complexes: Preparation, Characterization, and Properties of a Dinuclear EuIII Complex
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- 作者：Astrid Jä ; schke ; Marcus Kischel ; Alexander Mansel and Berthold Kersting
- 刊名：European Journal of Inorganic Chemistry
- 出版年：2017
- 出版时间：February 03, 2017
- 年：2017
- 卷：2017
- 期：5
- 页码：894-901
- 全文大小：1783K
- ISSN：1099-0682c
文摘
The synthesis of calixarene-based N4O4-donor ligand H6L, in which two 8-hydroxyquinoline-2-carbaldehyde units are appended via hydrazone-carbonylmethoxy linkages in a 1,3 arrangement to the lower rim of tert-butylcalix[4]arene, and its coordination properties towards EuIII are described. The reaction of H6L with Eu(NO3)3·6H2O produced dinuclear complex [Eu2(H3L)2(MeCN)2] (4). The EuIII ions in 4 are well separated from each other (d > 8 Å) and each is coordinated by two tetradentate hydroxyquinoline-2-carbaldehyde hydrazone substituents from two triply deprotonated (H3L)3– ligands in a dodecahedral geometry. As a consequence there are no exchange interactions between the EuIII ions, and the magnetic properties are solely associated with thermal population of excited (7F1–7F6) terms. The spin–orbit coupling constant λ is 325.2(4) cm–1. Moreover, H6L was found to extract EuIII and TbIII from aqueous solution at pH 7–8, as established by radiotracing with 160Tb and 152Eu.