Metal complexes in solvent extraction studies—III Preparation and investigation of binary and ternary complexes

Abstract

Some ternary complexes of the type M(chelate) 2S x [M = UO 2 2+, Cu 2+, Zn 2+, Ni 2+, Co 2+, chelate = TTA (thenoyltrifluoroacetone anion), S = TBP (tri-n-butyl phosphate), TBEP (tri-n-butoxyethyl phosphate, TOPO (tri-n-octyl phosphine oxide), 4-me-py (4-methyl pyridine), TPPO (tri-phenyl-phosphine oxide)] have been prepared and investigated. Preliminary work has also been carried out with HFacac (hexafluoroacetylacetone anion), TFacac (trifluoroacetylacetone anion) and acac (acetylacetone anion) as chelates. The compounds Zn(HFacac) 2· xH 2O ( x = 1 and 2), Zn-(HFacac) 2(TOPO) 2, Cu(HFacac) 2TOPO, Co(acac) 2(4-me-py) 2, UO 2(acac) 2·4-me-py and UO 2(acac) 2 (TPPO) 3 have also been isolated. Solvent extraction studies show that the synergistic extraction of 65Zn depends upon the nature of the chelate and of S. It is suggested that the phenomenon of synergism involves both the stability of M(chelate) 2· xH 2O and M(chelate) 2S x and further, that the bonding of S, which is directly to the metal, is weak and comparable to solvation or adduct formation.