Synergistic Effect of Tris(4-isopropyltropolonato)cobalt(III) on the Extraction of Lanthanoid(III) with 2-Thenoyltrifluoroacetone

Abstract

Synergistic enhancement of the extraction of lanthanoid(III) (Ln) with 2-thenoyltrifluoroacetone (Htta) in benzene has been found by the addition of tris(4-isopropyltropolonato)cobalt(III) (Co(ipt)3). The synergistic effect of Co(ipt)3 was ascribed to the formation of a 1:1 adduct of Ln(tta)3 with Co(ipt)3, i.e., a binuclear complex, in the organic phase. The adduct formation constant (beta s,1) determined by the extraction equilibrium analysis was reasonably consistent with that determined by spectrophotometry. The beta s,1 values decreased with increase in the atomic number of Ln and showed a large difference between light and heavy Ln. Spectroscopic studies were performed to explain the difference in the beta s,1 values. Electronic absorption spectra showed that the change in the structure of Co(ipt)3 complexed with the light Ln chelate is larger than that with the heavy Ln. The IR spectra showed the displacement of the coordinated water molecules of the light Ln chelates with Co(ipt)3. On the other hand, the adduct formation of heavy Ln was caused by the hydrogen bonding between Co(ipt)3 and the coordinated water of the Ln chelate.

Synergistic Effects of Tris(4-isopropyltropolonato)cobalt(III) on the Extraction of Lanthanum(III) and Lutetium(III) with Acetylacetone into Benzene

“…The adduct formation constants obtained were compared with those reported previously [2,3,5]. Table 1 lists the adduct formation constants (log  s,1 ) for the Ln(-diketone) 3 with the Co(III) chelate in benzene.…”

“…Tris(carbonato)cobalate(III) was prepared by the usual method [8]. Purification and identification of Co(ipt) 3 were performed in a same manner as reported previously [5]. The identification by the elemental analysis, 1 H-NMR (JEOL GSX-400), and HPLC (JASCO) showed that the Co(ipt) 3 obtained was a high purity and single geometric meridional isomer.…”

“…Recently, we have found a novel synergistic effect of some metal chelates on the extraction of lanthanide ions (Ln 3+ ) with -diketones. For example, tris(acetylacetonato)cobalt(III) (Co(acac) 3 ) [1][2][3][4], tris(4-isopropyltropolonate)cobalt(III) (Co(ipt) 3 ) [4,5], tris(8-quinolinolate)cobalt(III) (Co(q) 3 ) [6], and tris(acetylacetonato)chromium(III) [7] act as synergists in the extraction of Ln(III) with acetylacetone (Hacac), 2-thenoyltrifluoroacetone (Htta), or hexafluoroacetylacetone. This phenomenon was attributed to adduct formation between the extracted Ln(-diketone) 3 and the cobalt(III) or Solvent Extraction Research and Development, Japan, Vol.…”

Synergistic Extraction of Lanthanides(III) with 2-Thenoyltrifluoroacetone and Pyridine as Ion-Pairs and Adducts

“…Early studies of the synergistic extraction of Ln(III) have been comprehensively reported wherein Htta (2-thenoyltrifluoroacetone) was used as the -diketone together with Lewis bases with O-donor atoms such as tributyl phosphate and trioctylphosphine oxide [1][2][3]. The use of carboxylic acids [3][4][5], tris(-diketonato)metal(III) [6,7], linear polyethers [8,9], and crown ethers [10][11][12][13][14][15] as Lewis bases has also been reported. In general, the extractability of Ln(III) with the -diketone itself increases but the Solvent Extraction Research and Development, Japan, Vol.…”

Co-extraction of Lanthanoid(III) with Various Metal Ions in the Chelate Extraction System with Acetylacetone

“…In our recent studies, it has been found that the extraction of lanthanoid ion (Ln 3+ ) with 2-thenoyltrifluoroacetone (Htta) is highly enhanced by the addition of tris(acetylacetonato)-metals(III) of chromium(III) 2 and cobalt(III), 3,4 tris(8-quinolinolato)cobalt(III) 5 or tris(4-isopropyltropolonato)cobalt(III) 6 in the organic phase. These remarkable phenomena were attributed to the adduct formation between Ln(tta)3 extracted and those inert chromium(III) or cobalt(III) chelates in the organic phase.…”