A TRLFS study on the complexation of Cm(III) and Eu(III) with 4-t-butyl-6,6´-bis-(5,6-diethyl-1,2,4-tiazin-3-yl)-2,2´-bipyridine in a water / 2-propanol mixture

The complexation of Cm(III) and Eu(III) with 4-t-butyl-6,6´-bis-(5,6-diethyl-1,2,4-tiazin-3-yl)-2,2´-bipyridine(t-Bu-C2-BTBP) in water / 2-propanol solution is studies.JRC.E-Institute for Transuranium Elements (Karlsruhe

NMR and TRLFS studies of Ln(III) and An(III) C5-BPP complexes

C5-BPP is a highly efficient N-donor ligand for the separation of trivalent actinides, An(III), from trivalent lanthanides, Ln(III). The molecular origin of the selectivity of C5-BPP and many other N-donor ligands of the BTP-type is still not entirely understood. We present here the first NMR studies on C5-BPP Ln(III) and An(III) complexes. C5-BPP is synthesized with 10% 15N labeling and characterized by NMR and LIFDI-MS methods. 15N NMR spectroscopy gives a detailed insight into the bonding of C5-BPP with lanthanides and Am(III) as a representative for trivalent actinide cations, revealing significant differences in 15N chemical shift for coordinating nitrogen atoms compared to Ln(III) complexes. The temperature dependence of NMR chemical shifts observed for the Am(III) complex indicates a weak paramagnetism. This as well as the observed large chemical shift for coordinating nitrogen atoms show that metal–ligand bonding in Am(C5-BPP)3 has a larger share of covalence than in lanthanide complexes, confirming earlier studies. The Am(C5-BPP)3 NMR sample is furthermore spiked with Cm(III) and characterized by time-resolved laser fluorescence spectroscopy (TRLFS), yielding important information on the speciation of trace amounts of minor complex species

Complexation and thermodynamics of Cm(III) at high temperatures: the formation of [Cm(SO4)n]3-2n (n=1,2,3) complexes at T=25 to 200°C

The formation of [Cm(SO4)n]3-2n (n=1,2,3) complexes in an aquatic solution is studies by time resolved laser fluorescence spectroscopy as a function of the ligand concentration, the ionic strength (NaCIO4) and the temperature (25 to 200 °C).JRC.E-Institute for Transuranium Elements (Karlsruhe

A thermodynamical and structural study on the complexation of trivalent lanthanides with a polycarboxylate based concrete superplasticizer

Thermodynamic data for the complexation of Eu(iii) with a polycarboxylate based concrete superplasticizer are determined by TRLFS. These results are complemented by structural data of the respective Gd(iii) and Tb(iii) complexes which are obtained using EXAFS spectroscopy.</p

TRLFS and EXAFS investigations of lanthanide and actinide complexation by triflate and perchlorate in an ionic liquid

The solvation of the Eu-perchlorate (ClO4–) and triflate (CF3SO3–, OTf–) salts as well as of Cm(ClO4)3 and Am(ClO4)3 in the ionic liquid C4mimTf2N (1-butyl-3-methylimidazolium-bis(trifluoromethylsulfonyl)imide) has been comparatively investigated by application of laser fluorescence spectroscopy and X-ray absorption spectroscopy. Moreover, the ClO4–/OTf– ligand exchange reaction for the two actinide cations has been analyzed by the same spectroscopic techniques. A structural model for the different complexes was determined by the interpretation of the spectroscopic data. The lanthanide and the two actinide cations show the same coordination in C4mimTf2N. Moreover, a sequence for the strength of complexing ligands could be deduced from the spectroscopic data for the lanthanide and the two actinides: ClO4–>OTf–≥Tf2N–>H2O

Time-Resolved Laser Fluorescence Spectroscopy and Extended X-Ray Absorption Spectroscopy Investigations of the N3- Complexation of Eu(III), Cm(III), and Am(III) in an Ionic Liquid: Differences and Similarities

The complexation of the lanthanide Eu(III) and the actinides Cm(III) and Am(III) by N-3(-) was investigated by application of time-resolved laser fluorescence spectroscopy (TRLFS) and X-ray absorption spectroscopy (XAFS) in the ionic liquid solution Of C(4)mimTf(2)N (1-butyl-3-methylimidazolium-bis(trifluoromethylsulfonyl)imide). TRLFS, measurements show that the interaction of azide with Eu(CF3SO3)(3) and Eu(ClO4)(3) results in both dynamic luminescence quenching by collisional encounters of N-3(-) with Eu(III) and static luminescence quenching by inner-sphere complexation of Eu(III) by N-3(-). Hereby, the complexation of Eu-triflate by azide starts at a lower N-3(-) concentration as compared to the perchlorate salt. The authors ascribe this phenomenon to a stronger bonding Of ClO4- toward the metal ion than triflate, as well as to a stronger electrostatic repulsion of N-3(-) by the perchlorate ligand. In both actinide samples (Cm(ClO4)(3), Am(ClO4)(3)), the complexation with azide exhibits a clear kinetic hindrance. Nevertheless, mixed actinide-perchlorate-azide complexes are formed after several days in C(4)mimTf(2)N. The different reaction kinetics for the Ln- and An-complexation by azide may provide the opportunity for an effective separation of lanthanides from actinides in the nuclear fuel cycle by the use of N-based extractants in ionic liquid solutio