Lanthanide and actinide extractions with anionic ligands based on cobalt bis(dicarbollide) ions with covalently bonded CMPO functions

Abstract

Compounds were synthesized with the aim to develop efficient extraction agents for liquid-liquid extraction of polyvalent cations, i.e. lanthanides and actinides from high-level activity nuclear waste. Compounds of general formulation [(8-CMPO-(CH 2 -CH 2 O) 2 -1,2-C 2 B 9 H 10 )(1 ,2 -C 2 B 9 H 11 )-3,3 -Co(III)] − with different phosphorus and nitrogen substitution (CMPO= 2 R, 3 R P(O)-(CH 2 ) n C(O)N 1 R, 1 R = t-octyl, H, Ph, 2 R=Ph, n-octyl, 3 R=Ph, n = 1,2)-(4a to 4e), were prepared and characterized by combination of 11 B NMR, 1 H high field NMR, ESI-M.S., HPLC and other techniques. Molecular structure of the sodium complex of ligand 4a ( 1 R = t-octyl, 2 R = 3 R = Ph, n = 1) was determined by single crystal X-ray diffraction analysis. Effect of several modifications in the structure of 4a-4e on the extraction properties was outlined. The study resulted in the definition of ionic ligand with enhanced extraction efficiency for 4a,b (t-octyl and H on the amidic nitrogen atom) and a better solubility of 4a and 4d ( 1 R = t-octyl, 2 R = n-Oct, 3 R=Ph, n = 1) in less polar solvents. Low polar mixtures of hydrogenated tetrapropylene (TPH) hexyl methyl ketone (HMK) can be applied as an auxiliary solvent for 4a, selected for detailed studies, replacing thus the polar and less environmentally friendly nitro-, fluoro-and chloro-solvents used in the current dicarbollide liquid-liquid extraction process. Results of the fission products separation from the simulated PUREX feed using 4a are presented inclusive procedures for Eu 3+ stripping.

Anionic alkyl diglycoldiamides with covalently bonded cobalt bis(dicarbollide)(1−) ions for lanthanide and actinide extractions

“…In our previous papers we reported on the synthesis of reactive building blocks comprising ammonium groups attached on the ionic cobalt bis(dicarbollide) cage [16,17,21], the methods based on 0022-328X/$ -see front matter Ó 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.jorganchem.2010.02.014 ring opening of the reactive dioxane cobalt bis dicarbollide derivative are also summarized in a recent review article [22].…”

“…These compounds of general formula [{(N,N-(8-CH 2 -CH 2 O) 2 -1,2-C 2 B 9 H 10 )(1 0 ,2 0 -C 2 B 9 H 11 )-3,3 0 -Co)(N 0 ,N 0 -R)NCOCH 2 } 2 O]-Na 2 , therefore contain two hydrophobic cobalt bis(dicarbollide) anions in the molecule along with two alkyl/aryl (R = n-C 4 H 9 , n-C 8 H 17 , n-C 12 H 25 , and 1-C 6 H 4 -4-CH 3 ) (1-4, see Scheme 1 and Table 1) substituents bonded at the amidic nitrogen atoms. The compounds were characterized by combination of 11 B, 1 H and 13 C NMR spectroscopy and ESI-MS and other methods their purity was also assayed by HPLC methods [23,17] being better than 98%.…”

“…Under typical experiments, the zwitterionic ammonium derivatives [(8-RNH 2 -(CH 2 -CH 2 O) 2 -1,2-C 2 B 9 H 10 )(1 0 ,2 0 -C 2 B 9 H 11 )-3,3 0 -Co] 0 (R = n-C 4 H 9 , n-C 8 H 17 , n-C 12 H 25 , -C 6 H 4 -4-CH 3 ) prepared by known general procedure [16,17] [22] (3.6 mmol) were dried in vacuum at 60°C for 12 h, then dissolved in THF (100 ml) and treated with solid NaH (95%, 360 mg, 14.4 mmol). The slurry was stirred at room temperature for 2 h. and then diglycolyl acid dichloride (95%, Aldrich 210 lL, 1.8 mmol) in THF (10 ml) was dropwise added from syringe during 60 min.…”

“…In past years we have focused on covalent combinations of cobalt bis(dicarbollide) ion with functional groups that are able to bond trivalent lanthanides and actinides, particularly these containing CMPO functions, where the markedly high effect of covalent bonding of was observed [16][17][18][19][20]. In this paper we report in preliminary fashion on another new and efficient family of compounds consisting of molecular scaffold resembling organic TODGA molecule, but bearing two ionic cobalt bis(dicarbollide) groups.…”

Syntheses of C-substituted icosahedral dicarbaboranes bearing the 8-dioxane-cobalt bisdicarbollide moiety

“…These reactions represent an important feature of substitution boron chemistry and many examples can be found in the literature of these last years [4][5][6][7][8][9][10]. Moreover, a recent exhaustive review by Semioshkin et al [11] has been published on this field.…”