Separation of Uranium(VI) by Extraction with Dibutylditiophosphoric Acid

The extraction of uranium(VI) from aqueous solutions with dibutylditiophosphoric acid in organic solvents was studied. The influence of different factors as pH of the aqueous phase, extractant concentration and nature of solvent was investigated in order to find the optimum conditions for separation of metal from aqueous nitrate solutions. The effect of neutral donor extractants was also searched and the efficiency of the extraction was calculated.     

Separation of uranium(VI) from Fe(II), Ni(II), Co(II) and Cu(II) by electrophoresis using diethyldithiophosphoric acid

Paper electrophoresis has been used for uranium(VI) separation from Fe(II), Co(II), Ni(II) and Cu(II). The background electrolyte (0.1M HNO₃-NaNO₃) at different pH values contains diethyldithiophosphoric acid as complexing agent. A plot of mobility versus pH is used to obtain information on the formation of dithiophosphate complexes and to compute the stability constant of an uranyldiethyldithiophosphate complex.     

Synthesis and characterization of optically active and racemic forms of cyclometalated Rh(III) complexes. An experimental and theoretical emission study

The optically active cyclometalated Rh(III) complexes, delta[Rh(thpy4,5p(R,R)py)(2)TAP]Cl, lambda[Rh(thpy4,5p(S,S)py)(2)TAP]Cl, and delta[Rh(phpy4,5p(R,R)py)(2)TAP]Cl (where TAP = 1,4,5,8-tetraazaphenanthrene, thpy4,5p(R,R)py = (8R,10R)-2-(2'-thienyl)-4,5-pinenopyridine and phpy4,5p(R,R)py = (8R,10R)-2-(2'-phenyl)-4,5-pinenopyridine) have been prepared and characterized. Their photophysics has been examined in parallel with that of rac[Rh(thpy)(2)TAP]Cl and rac[Rh(phpy)(2)TAP]Cl. Their behaviors have been rationalized from results of TD-DFT calculations. The complexes with thienylpyridine (thpy) as cyclometalating ligands exhibit (3)CT (from thpy to TAP) and (3)LC(pi-pi) (centered on thpy) emissions in a solvent matrix at 77 K and one (3)CT luminescence at room temperature. In contrast, with phenylpyridine (phpy), the complexes show only one (3)CT emission (from phpy to TAP) at both temperatures.     

Synthesis and TG/DTA study on two new metallo(VI)-arsenato(V) heteropolyacids containing vanadium(V)

An improved method for the synthesis of two heteropolyacids of the same type: H₅[AsMo₁₀V₂O₄₀]·13H₂O and H₅[AsW₁₀V₂O₄₀]·16H₂O was elaborated. The studied compounds were characterized by elemental analysis, IR spectra and thermal behaviour over 20-800°C temperature range.This revised version was published online in November 2005 with corrections to the Cover Date.     

Spectroscopic,Magnetic and Thermal Investigations on Cu(II), Mn(II), Co(II) and Fe(III) Complexes with Glutamyl Nitroanilide

New complexes CuL₂×2H₂O, CoL₂×3H₂O, MnL₂×2H₂O and FeL₃×2H₂O, L=γ-L -glutamyl-5-(p-nitroanilide), were synthesized and characterized by their spectral, magnetic and thermal properties. The thermal stabilities of the synthesized complexes were examined in the temperature range 20–500°C. In all these complexes γ-L -glutamyl-5-(p -nitroanilide) acts as a bidentate ligand, its coordination involving the carbonyl oxygen and the nitrogen atom of the second amino group. The local structure around the Cu(II) ion is pseudotetrahedral. In the Co(II), Mn(II) and Fe(III) complexes, the metal ions are in the high-spin form, with octahedral stereochemistry. This revised version was published online in August 2006 with corrections to the Cover Date.     

Divalent transition metal complexes

4-(4-ethoxy-phenylhydrazono)-1-phenyl-3-methyl-1H-pyrazolin-5(4H)-one (5a) (H-EMPhP) as ligand and its Cu(II), Co(II) and Ni(II) complexes 4(a-c) were synthesized and characterized by their thermal and spectral properties. The azocoupling product (H-EMPhP), able of azo-hydrazone tautomerism 5(a-d), act as a bidentate ligand involving in coordination the azogroup nitrogen of its common anion (7) and the oxygen atom that is bound to the pyrazole ring of the mentioned anion (7).     

Thermal Behaviour Studies on Some Heterotrinuclearpolyacids

An improved method for the synthesis of four heterotrinuclearpolyacids of the type: H_x[EM′_yM″_zO₄₀⋅nH₂O (E=P, Si; M′=Mo, W; M″=V, W) was elaborated. The studied compounds were characterized by elemental analysis, IR spectra and thermal behaviour over 20–800°C temperature range. This revised version was published online in August 2006 with corrections to the Cover Date.