Comparative investigation of N donor ligand-lanthanide complexes from the metal and ligand point of view
International audience N-donor ligands such as n-Pr-BTP (2,6-bis(5,6-dipropyl-1,2,4-triazin-3-yl)pyridine) studied here preferentially bind An(III) over Ln(III) in liquid-liquid separation of trivalent ac-tinides from spent nuclear fuel. The chemical and physical processes responsible for this selec...
Published in: | Journal of Physics: Conference Series |
---|---|
Main Authors: | , , , , , , , , , , , , , , , |
Other Authors: | , , , , , |
Format: | Conference Object |
Language: | English |
Published: |
HAL CCSD
2012
|
Subjects: | |
Online Access: | https://hal.archives-ouvertes.fr/hal-01572871 https://hal.archives-ouvertes.fr/hal-01572871/document https://hal.archives-ouvertes.fr/hal-01572871/file/J_Phys_Conf_Series_430_012115.pdf https://doi.org/10.1088/1742-6596/430/1/012115 |
Summary: | International audience N-donor ligands such as n-Pr-BTP (2,6-bis(5,6-dipropyl-1,2,4-triazin-3-yl)pyridine) studied here preferentially bind An(III) over Ln(III) in liquid-liquid separation of trivalent ac-tinides from spent nuclear fuel. The chemical and physical processes responsible for this selectivity are not yet well understood. We present systematic comparative near-edge X-ray absorption structure (XANES) spectroscopy investigations at the Gd L-3 edge of [GdBTP3](NO3)(3), [Gd(BTP)(3)](OTf)(3), Gd(NO3)(3), Gd(OTf)(3) and N K edge of [Gd(BTP)(3)](NO3)(3), Gd(NO3)(3) complexes. The pre-edge absorption resonance in Gd L3 edge high-energy resolution X-ray absorption near edge structure spectra (HR-XANES) is explained as arising from 2p(3/2) -> 4f/5d electronic transitions by calculations with the FEFF9.5 code. Experimental evidence is found for higher electronic density on Gd in [Gd(BTP)(3)](NO3)(3) and [Gd(BTP)(3)](OTf)(3) compared to Gd in Gd(NO3)(3) and Gd(OTf)(3), and on N in [Gd(BTP)(3)](NO3)(3) compared to n-Pr-BTP. The origin of the pre-edge structure in the N K edge XANES is explained by density functional theory (DFT) with the ORCA code. Results at the N K edge suggest a change in ligand orbital occupancies and mixing upon complexation but further work is necessary to interpret observed spectral variations |
---|