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Title: Calix[4]arenes as selective extracting agents. An NMR dynamic and conformational investigation of the lanthanide(III) and thorium(IV) complexes

Abstract

The lanthanide and Th{sup 4+} complexes with calix[4]arene ligands substituted either on the narrow or at the wide rim by four coordinating groups behave totally differently as shown by an NMR investigation of the dia- and paramagnetic complexes. Solutions of complexes were prepared by reacting anhydrous metal perchlorate salts with the ligands in dry acetonitrile (CAUTION). Relaxation time T{sub 1} titrations of acetonitrile solutions of Gd{sup 3+} by calixarenes indicate that ligands substituted on the narrow rim form stable 1:1 complexes whether they feature four amide groups (1) or four phosphine oxide functions. In contrast, a ligand substituted by four (carbamoylmethyl)-diphenylphosphine oxide moieties on the wide rim (3) and its derivatives form polymeric species even at a 1:1 ligand/metal concentration ratio. Nuclear magnetic relaxation dispersion (NMRD) curves (relaxation rates 1/T{sub 1} vs magnetic field strength) of Gd{sup 3+}, Gd{sup 3+}{center_dot}1 and Gd{sup 3+}{center_dot}3 perchlorates in acetonitrile are analyzed by an extended version of the Solomon-Bloembergen-Morgan equations. A comparison of the calculated rotational correlation times {tau}{sub r} shows that ligand 3 forms oligomeric Gd{sup 3+} species. The chelates of ligand 1 are axially symmetric (C{sub 4} symmetry), and the paramagnetic shifts induced by the Yb{sup 3+} ion are accounted for quantitatively.more » The addition of water or of nitrate ions does not modify the geometry of the complex. The metal chelates of 3 and its derivatives adopt a C{sub 2} symmetry, and the paramagnetic shifts are interpreted on a semiquantitative basis only. Water and NO{sub 3}{sup {minus}} ions completely labilize the complexes of the heavy lanthanides. The very high selectivity of ligand 3 through the lanthanide series stems from a complex interplay of factors.« less

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Univ. of Liege (BE)
OSTI Identifier:
20075873
Resource Type:
Journal Article
Journal Name:
Inorganic Chemistry
Additional Journal Information:
Journal Volume: 39; Journal Issue: 10; Other Information: PBD: 15 May 2000; Journal ID: ISSN 0020-1669
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; CALIXARENES; RARE EARTH COMPLEXES; THORIUM COMPLEXES; SOLVENT EXTRACTION; NUCLEAR MAGNETIC RESONANCE; RADIOACTIVE WASTE PROCESSING

Citation Formats

Lambert, B., Jacques, V., Shivanyuk, A., Matthews, S.E., Tunayar, A., Baaden, M., Wipff, G., Boehmer, V., and Desreux, J.F. Calix[4]arenes as selective extracting agents. An NMR dynamic and conformational investigation of the lanthanide(III) and thorium(IV) complexes. United States: N. p., 2000. Web. doi:10.1021/ic990683n.
Lambert, B., Jacques, V., Shivanyuk, A., Matthews, S.E., Tunayar, A., Baaden, M., Wipff, G., Boehmer, V., & Desreux, J.F. Calix[4]arenes as selective extracting agents. An NMR dynamic and conformational investigation of the lanthanide(III) and thorium(IV) complexes. United States. doi:10.1021/ic990683n.
Lambert, B., Jacques, V., Shivanyuk, A., Matthews, S.E., Tunayar, A., Baaden, M., Wipff, G., Boehmer, V., and Desreux, J.F. Mon . "Calix[4]arenes as selective extracting agents. An NMR dynamic and conformational investigation of the lanthanide(III) and thorium(IV) complexes". United States. doi:10.1021/ic990683n.
@article{osti_20075873,
title = {Calix[4]arenes as selective extracting agents. An NMR dynamic and conformational investigation of the lanthanide(III) and thorium(IV) complexes},
author = {Lambert, B. and Jacques, V. and Shivanyuk, A. and Matthews, S.E. and Tunayar, A. and Baaden, M. and Wipff, G. and Boehmer, V. and Desreux, J.F.},
abstractNote = {The lanthanide and Th{sup 4+} complexes with calix[4]arene ligands substituted either on the narrow or at the wide rim by four coordinating groups behave totally differently as shown by an NMR investigation of the dia- and paramagnetic complexes. Solutions of complexes were prepared by reacting anhydrous metal perchlorate salts with the ligands in dry acetonitrile (CAUTION). Relaxation time T{sub 1} titrations of acetonitrile solutions of Gd{sup 3+} by calixarenes indicate that ligands substituted on the narrow rim form stable 1:1 complexes whether they feature four amide groups (1) or four phosphine oxide functions. In contrast, a ligand substituted by four (carbamoylmethyl)-diphenylphosphine oxide moieties on the wide rim (3) and its derivatives form polymeric species even at a 1:1 ligand/metal concentration ratio. Nuclear magnetic relaxation dispersion (NMRD) curves (relaxation rates 1/T{sub 1} vs magnetic field strength) of Gd{sup 3+}, Gd{sup 3+}{center_dot}1 and Gd{sup 3+}{center_dot}3 perchlorates in acetonitrile are analyzed by an extended version of the Solomon-Bloembergen-Morgan equations. A comparison of the calculated rotational correlation times {tau}{sub r} shows that ligand 3 forms oligomeric Gd{sup 3+} species. The chelates of ligand 1 are axially symmetric (C{sub 4} symmetry), and the paramagnetic shifts induced by the Yb{sup 3+} ion are accounted for quantitatively. The addition of water or of nitrate ions does not modify the geometry of the complex. The metal chelates of 3 and its derivatives adopt a C{sub 2} symmetry, and the paramagnetic shifts are interpreted on a semiquantitative basis only. Water and NO{sub 3}{sup {minus}} ions completely labilize the complexes of the heavy lanthanides. The very high selectivity of ligand 3 through the lanthanide series stems from a complex interplay of factors.},
doi = {10.1021/ic990683n},
journal = {Inorganic Chemistry},
issn = {0020-1669},
number = 10,
volume = 39,
place = {United States},
year = {2000},
month = {5}
}