Synergic extraction of cobalt(II) by thenoyltrifluoroacetone and some amine extractants in chloroform

Synergic extraction of Co²⁺ with thenoyltrifluoroacetone and eight different amines in chloroform was investigated. It is found that the extracted adducts have the general formula Co(TTA)₂·B, where B stands for the amine. The stability sequence of the adducts obtained as related to the different classes of benzylamines is; dibenzylamine > benzylamine ⩽ tribenzylamine. A linear decrease in log β with the increase of Taft inductive constant was obtained on using tertiary long chain alkylamines as synergic ligand. UV and IR spectroscopic investigations support the direct bonding of the amine to the metal.     

Mixed complexes of ruthenium(III) and ruthenium(II) with triphenylphosphine or triphenylarsine and other ligands

The reactions of [RuCl₃(AsPh₃)₃] with ligands containing nitrogen (ammonia, hydrazines, amine and thiocyanate) and oxygen (carboxylates) and the reactions of β-diketones (acetylacetone, dibenzoylmethane and benzoylacetone) with [RuCl₂(PPh₃)₂]_n and [RuCl₂(AsPh₃)₂]₂ have been studied. Apart from this, a new Ru(III) complex, [RuBr₃(AsPh₃)₃] has also been synthesized. The compounds obtained have been characterised by analyses, conductivity and magnetic measurements, molecular weight and spectral studies (IR and visible). An equilibrium between hexacoordinated and pentacoordinated species is suggested on the basis of electronic spectral studies.     

Ruthenium(II) complexes with triphenylphosphine or triphenylarsine and other monodentate ligands

Synthesis and studies on some five-coordinate ruthenium(II) complexes, viz. [Ru(MPh₃)(C₆H₅CHO)₂Cl₂] and [Ru(MPh₃)₂(CO)Cl₂] (where M = P or As) have been described. Reactions of [Ru(MPh3)(C₆H₅CHO)₂Cl₂] with N,N-dimethylformamide, dimethylsulphoxide and pyridine and of [Ru(MPh₃)₂(CO)Cl₂] with pyridine are described.     

Ruthenium(II) complexes containing bidentate Schiff bases and triphenylphosphine or triphenylarsine

Reactions of ruthenium(II) complexes [RuHX(CO)(EPh₃)₂(B)] (X = H or Cl; B = EPh₃, pyridine (py) or piperidine (pip); E = P or As) with bidentate Schiff base ligands derived by condensingo- hydroxyacetophenone with aniline,o- orp-methylaniline have been carried out. The products were characterized by analytical, IR, electronic and¹H-NMR spectral studies and are formulated as [Ru(X)(CO) (L)(EPh₃)(B)] (L = Schiff base anion; X = H or Cl; B = EPh₃, py or pip; E = P or As). An octahedral structure has been tentatively proposed for the new complexes. The new complexes were tested for their catalytic activities in the oxidation of benzyl alcohol to benzaldehyde.     

Benchmark compounds. Structures of cobalt(II) complexes of triphenylphosphine- and triphenylarsine oxides

The structures of the Co(OPPh₃)₂Cl₂, Co(OPPh₃)₂Br₂, Co(OPPh₃)₂I₂, Co(OAsPh₃)₂Br₂ and Co(OAsPh₃)₂(NO₃)₂ complexes have been determined by X-ray diffraction methods; all have pseudo-tetrahedral co-ordination for cobalt.     

Thermodynamics of the extraction of Eu3+ with thenoyltrifluoroacetone,triphenylarsine oxide and other phosphine oxides

Extraction of Eu³⁺ from 0.1M aqueous perchlorate medium by thenoyltrifluoroacetone (HTTA) and by mixtures of HTTA and tributylphosphate (TBP), HTTA and triphenylphosphine oxide (TPPO), HTTA and trioctylphosphine oxide (TOPO) and HTTA and triphenylarsine oxide (TPAsO) has been studied at various temperatures allowing for the elucidation of the mechanism of extraction in each case and a comparison between the various bases.     

Complexes formed in the chloroform extraction of cobalt(II) with oxine

Absorption spectra of cobalt-oxine complexes-extractedinto chloroform indicate that two cobalt(II) and one cobalt(III) complexes can be extracted depending on pH and the initial concentrations of oxine in the organic phase or cobalt(II) ion in the aqueous phase. The oxidation state of cobalt in the complexes was determined by treatment of organic extracts with an 0.001 M EDTA solution at pH 4–5; cobalt(II) complexes were back-extracted, and the cobalt(III) complex was not. The equilibrium distribution ratios of cobalt(II) between aqueous perchlorate solutions and oxine solutions in chloroform were determined at 20°. A plot of logD_co-log[HO_x]_o vs. pOx gave a single curve for different concentrations of oxine; it was concluded that cobalt(II) is extracted as C_oOx₂HOx.     

The extraction of mercury(II), silver(I), cobalt(II) and cadmium(II) by dioctylarsinic acid in chloroform

Dioctylarsinic acid (HDOAA) in chloroform solution has been investigated as a reagent for the extraction of Hg(II), Ag(I), Co(II), and Cd(II). Silver, cobalt and cadmium are not extracted below pH 7. An extraction coefficient of 1.1, constant over the pH range 1–6.5, was observed for Hg(II). With HCl concentrations of 1–8 M the extractability of mercury decreased slowly, reaching E_a⁰ = 0.05 at 8 M HCl. Silver formed a silver dioctylarsinate precipitate which collected at the interface. The extraction coefficients for Hg(II), Co(II) and Cd(II) increased above pH 7 to values of 20 (pH 9.1), 30 (pH 8.0), and 23 (pH 10), respectively. Reagent- and pH-dependence studies indicated that Co(II) and Cd(II) are extracted as M(DOAA)₂ or M(DOAA)Cl through interaction of HDOAA with M(OH)₂ or M(OH)⁺. Mercury was extracted from solutions of pH 1–6.5 as HgCl₂ (HDOAA)_2.5.     

Ruthenium(III) complexes with tetradentate Schiff bases containing triphenylphosphine or triphenylarsine

Ruthenium(III) complexes of Schiff bases derived from the condensation of salicylaldehyde or o-vanillin with diamines have been prepared and characterised. The complexes are of the type [RuX(EPh₃)(L)] [X=Cl or Br; E=P or As; L=bis(salicylaldehyde)tetramethylenediimine, bis(salicylaldehyde)o-phenylenediimine, bis(o-vanillin)ethylenediimine, bis(o-vanillin)propylenediimine, bis(o-vanillin)tetramethylenediimine or bis(o-vanillin)o-phenylenediimine]. The Schiff bases behave as dibasic tetradentate ligands.     

Synergistic extraction of cobalt(II) with oxine/decanoic acid solution mixtures in benzene and chloroform

Synergistic extraction of Co(II) with 8-hydroxyquinoline (Hq)/decanoic acid [(HR)₂] solution mixtures in benzene and chloroform was carried out at 25°C. The aqueous ionic strength and the total concentration of cobalt(II) were 0.1 (NaCl) and 1·10^–5–1·10^–3M, respectively. The synergistic effect is interpreted by the formation of the mixed ligand ion-pair complexes: [(Coq(Hq)₂(HR))⁺, R^–] and [(Coq(Hq)₂(HR)₃)⁺, R^–] in benzene and chloroform, respectively.     

Effects of axial ligand on the oxidation of triphenylphosphine catalyzed by nitro(tetraphenylporphyrinato)cobalt complexes

Nitro(tetrahenylporphyrinato)cobalt complexes catalyze the oxidation of triphenylphosphine to triphenylphosphine oxide by molecular oxygen. The effects of axial ligands in the nitro cobalt complexes on this oxidation reaction were studied. 4-Cyanopyridine gave the best yield. This result suggests that the more unstable is nitro(tetraphenylporphyrinato)cobalt complex the better the yield obtained.     

Synthesis, spectroscopic characterization, redox properties and catalytic activity of some ruthenium(II) complexes containing aromatic aldehyde and triphenylphosphine or triphenylarsine

A series of new mixed ligand penta-coordinated square pyramidal ruthenium(II) complexes containing benzaldehyde or its substituents and triphenylphosphine or triphenylarsine have been synthesized and characterized. In the electronic spectra, three well-defined peaks in the visible region were observed and assigned to d-d transitions in D(4h) and low spin axially distortion from O(h) symmetry. The spectrochemical parameters of the complexes were calculated and placed the ligands in the middle of the spectrochemical series. The redox properties and stability of the complexes toward oxidation were related to the electron-withdrawing or releasing ability of the substituent in the phenyl ring of the benzaldehyde. The electron-withdrawing substituents stabilized Ru(2+) complexes, while electron-donating groups favored oxidation to Ru(3+). The mechanism and kinetics of the catalytic oxidation of benzyl alcohol by the complex [RuCl(2)(Pph(3))(C(6)H(5)CHO)(2)] in the presence of N-methylmorpholine-N-oxide have also been studied.     

The photolysis of Chlorocarbonylbis(triphenylphosphine)iridium(I) in chloroform

Under 254 or 313 nm irradiation in chloroform, [IrCl(CO)(PPh3)2] is converted cleanly to [IrCl2(CO)H(PPh3)2] through the addition of HCl, produced photochemically. Under 254 nm irradiation, some of the reaction of [IrCl(CO)(PPh3)2] occurs by direct photolysis of chloroform, though a greater contribution arises from a reaction initiated through absorption of light by the metal complex. Under 313 nm irradiation, essentially all of the reaction is metal-initiated. The linear dependence of the reaction rate on light intensity and on the fraction of light absorbed by the Ir(I) complex as well as the lack of a deuterium isotope effect rule out a radical process. Instead it is proposed that an association complex between excited state [IrCl(CO)(PPh3)2] and CHCl3 leads to dissociation of a chlorine atom from CHCl3, yielding HCl after abstraction of a hydrogen from another CHCl3. HCl then adds to a ground state [IrCl(CO)(PPh3)2] complex.     

Isolation of the mixed ligand complex of beryllium(II) with acetylacetone and thenoyltrifluoroacetone by gel permeation chromatography

Summary The mixed ligand, metal complex (acetylacetonato) (thenoryltrifluoroacetonato) beryllium(II) has been isolated from a reaction mixture of bis(acetylacetonato) beryllium(II) and bis(thenoyltrifluoroacetonato)beryllium(II) in ethyl acetate by gel permeation chromatography using Shodex 801 gel column and ethyl acetate as the solvent.     

Synergistic extraction of cobalt(II) by tri-octylamine and neutral donors

This work reports a study on the synergistic extraction of cobalt(II), spiked with⁶⁰Co from hydrochloric acid solutions by mixtures of trioctylamine (TOA) and neutral organophosphorous donors into carbon tetrachloride. Synergistic coefficients and adduct formation constants have been evaluated from distribution measurements and correlated with the basic character of donors.     

Mixed ligand cobalt(II) picolinate complexes: synthesis, characterization, DNA binding and photocleavage

Complexes of the type [Co(pic)(2)(NN)], where pic = picolinate, NN = dipyrido[3,2-d:2',3'-f]quinoxaline (dpq) (4) and 4b,5,7,7a-tetrahydro-4b,7a-epiminomethanoimino-6H-imidazo[4,5-f][1,10]-phenanthroline-6,13-dione (bipyridyl-glycoluril) (bpg) (6) have been synthesized and characterized by elemental analysis, IR, UV-vis, NMR and ESI-MS spectroscopy and thermogravimetic analysis (TGA). Their physicochemical properties are compared with previously synthesized complexes, where NN = (H(2)O)(2) (1), 2,2'-bipyridine (bpy) (2), 1,10-phenanthroline (phen) (3) and dipyrido[3,2-a:2',3'-c]phenazine (dppz) (5). The crystal structures of the complexes 4-6 were solved by single-crystal X-ray diffraction. The complexes 4 and 5 crystallize from a mixture of chloroform and methanol in monoclinic and orthorhombic crystal systems, respectively, whereas complex 6 crystallizes from dimethyl sulfoxide (DMSO) in a tetragonal crystal system. The coordination sphere consists of two oxygen atoms and two nitrogen atoms from the two picolinates and two nitrogen atoms from the dpq, dppz or bpg ligand, respectively. Co(ii)/Co(iii) oxidation potentials have been determined by cyclic voltammetry. The DNA binding of complexes 1-5 has been investigated using thermal melting, fluorescence quenching and viscosity measurements, which indicate the partial intercalation of complex 5 with an apparent binding constant (k(app)) of 8.3 × 10(5) M(-1). DNA cleavage studies of complexes 1-5 have been investigated using gel electrophoresis in the presence of H(2)O(2) as an oxidizing agent and also by photoirradiation at 365 nm. The mechanistic investigations suggest that singlet oxygen ((1)O(2)) is the major species involved in the DNA cleavage by these complexes. The structures of complexes 2-6 were optimized with density functional theory (DFT) method (B3LYP/6-31G(d,p)). The low vertical ionization potential values indicate photoredox pathways for the DNA cleavage activity by complexes 4 and 5, which is corroborated by DNA cleavage experiments.     

Synergistic extraction of manganese(II) with thenoyltrifluoroacetone and neutral unidentate and bidentate ligands

Tritium content in tritiated titanium was measured by the method of fluorescent X-ray detection with an intrinsic Ge detector. The conventional method of setting region-of-interest of overlapped X-ray peaks was developed. The Ti K and K X-ray peak profile of³H/Ti was compared with that of V-49 electron capture standard source. Effect of geometry and sample thickness on peak profile was discussed. Detection limit in this method was 0.187 GBq of tritium.