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Solid state structure of thorium(IV) complexes with common aminopolycarboxylate ligands
1CEA, IRAMIS, UMR 3299 CEA/CNRS, SIS2M, LCCEf, Bât. 125, 91191 Gif-sur-Yvette, France. pierre.thuery@cea.fr
Inorganic Chemistry
|January 22, 2011
Summary
Thorium(IV) nitrate complexes with iminodiacetic acid, nitrilotriacetic acid, and ethylenediaminetetraacetic acid were synthesized and structurally characterized. These novel thorium-organic coordination polymers exhibit unique bridging and chelating ligand behaviors.
Area of Science:
- Inorganic Chemistry
- Coordination Chemistry
- Materials Science
Background:
- Thorium(IV) complexes are relevant for actinide decorporation and nuclear waste management.
- Aminopolycarboxylate ligands are extensively studied for their complexation behavior with actinides.
- Previous structural data for thorium(IV) complexes were primarily obtained through EXAFS spectroscopy.
Purpose of the Study:
- To report the crystal structures of thorium(IV) complexes with iminodiacetic acid (H(2)IDA), nitrilotriacetic acid (H(3)NTA), and ethylenediaminetetraacetic acid (H(4)EDTA) under hydrothermal conditions.
- To investigate the coordination modes and structural features of these thorium-organic complexes.
- To contribute novel structural information to the understanding of thorium(IV) interactions with aminopolycarboxylates.
Main Methods:
- Hydrothermal synthesis of thorium(IV) complexes.
- Single-crystal X-ray diffraction analysis to determine the crystal structures.
- Analysis of coordination environments and ligand binding modes.
Main Results:
- The crystal structures of three thorium(IV) complexes were determined: [Th(HIDA)(2)(C(2)O(4))]·H(2)O, [Th(NTA)(H(2)NTA)(H(2)O)]·H(2)O, and [Th(EDTA)(H(2)O)]·2H(2)O.
- Complex 1 features a ten-coordinate thorium ion chelated by HIDA(-) and oxalate ligands.
- Complex 2 exhibits a nine-coordinate thorium ion with both chelating and bridging H(3)NTA-derived ligands, including a novel bridging mode for H(2)NTA(-).
- Complex 3 shows a nine-coordinate thorium ion with EDTA(4-) acting as a chelating and bridging ligand.
- All complexes form two-dimensional assemblies, representing novel thorium-organic coordination polymers.
Conclusions:
- The study provides detailed structural insights into thorium(IV) complexes with H(2)IDA, H(3)NTA, and H(4)EDTA.
- The observed coordination modes, particularly the bridging behavior of H(2)NTA(-), expand the known structural chemistry of thorium(IV) aminopolycarboxylates.
- The formation of 2D coordination polymers highlights the potential for designing novel thorium-based materials.
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