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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.

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The reaction of the cobalt bis(dicarbollide)(1-)() ion in the presence of t-butylbromide, acting as a potent Lewis acid activator, leads to the clean substitution of by the N-atom of acetonitrile (or benzonitrile), thus resulting in the smooth formation of [(8-RCN)-1,2-C(2)B(9)H(10))(1',2'-C(2)B(9)H(11))-3,3'-Co(iii)](0) (R = CH(3) or C(6)H(5)) ( and ). These compounds can serve as versatile precursors for the generation of a variety of other synthetically useful functional groups. The nitrogen atom of the nitrile C[triple bond, length as m-dash]N- bond in and is prone to the facile addition of nucleophiles. Thus, alkaline hydrolysis of and in aqueous alcohols furnishes high yields of the corresponding B(8)-N-alkylamides [(8-RC(O)=NH)-1,2-C(2)B(9)H(10))(1',2'-C(2)B(9)H(11))-3,3'-Co(iii)](-), where R = CH(3) or C(6)H(5) ( and ). The reactions with butyl and diethyl amine result in the high-yield formation of 8-alkylamidine derivatives [(8-(3)R(2)RNH-(1)RC[double bond, length as m-dash]N)-1,2-C(2)B(9)H(10))(1',2'-C(2)B(9)H(11))-3,3'-Co(iii)](0), where (1)R = CH(3), (2)R = H, (3)R = C(4)H(9), (), (1)R = C(6)H(5), (2)R = (3)R = C(2)H(5) () or (1)R = C(6)H(5), (2)R = (3)R = C(2)H(5) (). Hydrazinolysis of provides a high yield of the zwitterionic [(8-H(3)N)-1,2-C(2)B(9)H(10))(1',2'-C(2)B(9)H(11))-3,3'-Co(iii)](0) (), whereas reduction of the nitrile group in and using BH(3).SMe(2) affords the respective alkylammonium derivatives [(8-RH(2)N)-1,2-C(2)B(9)H(10))(1',2'-C(2)B(9)H(11))-3,3'-Co(iii)](0), where R = -C(2)H(5) () or -CH(2)C(6)H(5) () in moderate yields. Compound can also be prepared by alkylation of along with dibenzylderivative (). A further example of alkylation is the ring cleavage of the 3-hydroxypropanesulfonic acid gamma-sultone producing a compound with alkyl ammonium sulfonic acid substitution [(8-O(3)SC(3)H(6)NH(2))-1,2-C(2)B(9)H(10))(1',2'-C(2)B(9)H(11))-3,3'-Co(iii)](-) () All new compounds were characterized by multinuclear NMR spectroscopy and mass spectrometry and the structures of compounds , , and were established by X-ray crystallography.