The structures of CyMe₄-BTBP complexes of americium(iii) and europium(iii) in solvents used in solvent extraction, explaining their separation properties

Abstract

Graphical abstractThe structure around the absorbing atom in the dicomplexes of 6,6'-bis (5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-benzo[1,2,4]triazin-3-yl) [2,2]bipyridine, CyMe4-BTBP, with americium(III) and europium(III) have been determined by means of Am and Eu L3 edge EXAFS spectroscopy in a series of solvents used to separate these metal ions using solvent extraction. The obtained structural information has been correlated with previously reported solubility and selectivity data as well as ionic radii in general terms.-3 -Abstract Separation of trivalent actinoid (An(III)) and lanthanoid (Ln(III)) ions is extremely challenging due to their similar ionic radii and chemical properties. Poly-aromatic nitrogen compounds acting as tetradentate chelating ligands to the metal ions in the extraction, have the ability to sufficiently separate An(III) from Ln(III). One of these compounds, 6,6'-bis (5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-benzol[1,2,4]

Separation of the Minor Actinides Americium(III) and Curium(III) by Hydrophobic and Hydrophilic BTPhen ligands: Exploiting Differences in their Rates of Extraction and Effective Separations at Equilibrium

“…30 In addition, CyMe4-BTPhen 3 and CyMe4-BTBP 2 both form identical 1:2 complexes with Cm(III) as shown by TRLFS studies, 31 while CyMe4-BTBP 2 forms a 1:2 complex with Am(III) as shown by EXAFS studies. 32 A single bidentate nitrate ion completes the inner coordination sphere in the Am(III) and Cm(III) 1:2 complexes of both ligands 2 and 3, which is in agreement with the solution and solid state structures of the corresponding lanthanide(III) complexes of 2 and 3. 33 It thus seems likely that in the present study, CyMe4-BTPhen 3 forms structurally identical 1:2 complexes with both Am(III) and…”

The coordination chemistry of CmIII, AmIII, and AcIIIin nitrate solutions: an actinide L3-edge EXAFS study

“…There is a report from Den Auwer on the Am(NO 3 ) 3 (TEMA) 2 complex, 72 another by Girnt on Am(NO 3 ) x (dmpbipy) x , 73 one by Bremer involving Am(NO 3 ) x (C5-BPP) x , 74 and finally Ekberg investigated [Am(NO 3 )(CyMe 4 -BTBP) 2 ] 2+ . 75 These studies showed an average Am–O NO 3 distance of 2.49 ± 0.01 Å. For Cm, numerous measurements have been made on NO 3 – species.…”

An overview of eight- and nine-coordinate N-donor solvated lanthanoid(III) and actinoid(III) ions

“…In solution, the europium(III) ion coordinates two BTBP ligands for a coordination number of eight, whereas a crystal structure precipitating from one of these solutions also includes a bidentately bound nitrate ion, making it effectively ten-coordinate [ 22 ]. Furthermore, when americium(III) was treated in the same way, it was found that the americium(III) ion thanks to its larger size coordinates a nitrate even in solution, and was determined to be at least nine-coordinate [ 23 ].…”