Sammanfattning

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.

Publicerad i

Journal of Physics: Conference Series
2013, Volym: 430

Konferens

15th International Conference on X-ray Absorption Fine Structure (XAFS15)

UKÄ forskningsämne

Fysikalisk kemi


Publikationens identifierare

DOI: https://doi.org/10.1088/1742-6596/430/1/012115

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/95523