Complexation of lanthanides, actinides and transition metal cations with a 6-(1,2,4-triazin-3-yl)-2,2′:6′,2′′-terpyridine ligand: implications for actinide(III)/lanthanide(III) partitioning

Lewis, F. W., Harwood, L. M. ORCID: https://orcid.org/0000-0002-8442-7380, Hudson, M. J., Drew, M. G.B., Sypula, M., Modolo, G., Whittaker, D., Sharrad, C. A., Videva, V., Hubscher-Bruder, V. and Arnaud-Neu, F. (2012) Complexation of lanthanides, actinides and transition metal cations with a 6-(1,2,4-triazin-3-yl)-2,2′:6′,2′′-terpyridine ligand: implications for actinide(III)/lanthanide(III) partitioning. Dalton Transactions, 41 (30). pp. 9209-9219. ISSN 1364-5447 doi: 10.1039/c2dt30522d

Abstract/Summary

The quadridentate N-heterocyclic ligand 6-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin- 3-yl)-2,2′ : 6′,2′′-terpyridine (CyMe4-hemi-BTBP) has been synthesized and its interactions with Am(III),U(VI), Ln(III) and some transition metal cations have been evaluated by X-ray crystallographic analysis, Am(III)/Eu(III) solvent extraction experiments, UVabsorption spectrophotometry, NMR studies and ESI-MS. Structures of 1 : 1 complexes with Eu(III), Ce(III) and the linear uranyl (UO2 2+) ion were obtained by X-ray crystallographic analysis, and they showed similar coordination behavior to related BTBP complexes. In methanol, the stability constants of the Ln(III) complexes are slightly lower than those of the analogous quadridentate bis-triazine BTBP ligands, while the stability constant for the Yb(III)complex is higher. 1H NMR titrations and ESI-MS with lanthanide nitrates showed that the ligand forms only 1 : 1 complexes with Eu(III), Ce(III) and Yb(III), while both 1 : 1 and 1 : 2 complexes were formed with La(III) and Y(III) in acetonitrile. A mixture of isomeric chiral 2 : 2 helical complexes was formed with Cu(I), with a slight preference (1.4 : 1) for a single directional isomer. In contrast, a 1 : 1 complex was observed with the larger Ag(I) ion. The ligand was unable to extract Am(III) or Eu(III) from nitric acid solutions into 1-octanol, except in the presence of a synergist at low acidity. The results show that the presence of two outer 1,2,4-triazine rings is required for the efficient extraction and separation of An(III)from Ln(III) by quadridentate N-donor ligands.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/29440
Item Type	Article
Refereed	Yes
Divisions	Interdisciplinary centres and themes > Chemical Analysis Facility (CAF) Life Sciences > School of Chemistry, Food and Pharmacy > Department of Chemistry
Uncontrolled Keywords	MULTIWAVELENGTH SPECTROSCOPIC DATA; SIMPLE LEGO SYSTEM; IONIZATION MASS-SPECTROMETRY; NUCLEAR-FUEL CYCLE; N-OXIDE COMPLEXES; EQUILIBRIUM-CONSTANTS; SOLVENT-EXTRACTION; CRYSTAL-STRUCTURES; COORDINATION CHEMISTRY; DONOR LIGANDS
Publisher	Royal Society of Chemistry
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