New Methods of Syntheses of Ammonium, Sodium & Potassium Triacetatodioxouranates (VI) & Diacetatodioxouranium (VI) Dihydrate

1048-104

Synthesis, characterisation, and some properties of molecular mixed-ligand peroxo complexes of uranium(VI) containing amines or aminocarboxylic acids as coligands

Molecular peroxo complexes of [UO2]2+, viz. [UO2(O2)(phen)](phen = 1,10-phenanthroline), [UO2(O2)(bipy)](bipy = 2,2'-bipyridyl), [UO2(O2)(en)](en = ethylenediamine), [UO2(O2)(H4edta)](H4edta = ethylenediamine-NNN'N'-tetra-acetic acid), and [UO2(O2)(gly)](gly = glycine), have been synthesised at different pH values of the reaction medium. They are diamagnetic. On the basis of spectroscopic evidence, both peroxide and each of the coligands, except gly, are co-ordinated to the metal in a bidentate manner, while gly occurs in its zwitterionic form and acts as a monodentate ligand. The complex [UO2(O2)(gly)] oxidises triphenylphosphine, cyclohexene, styrene, and SO2(g) to triphenylphosphine oxide, 1,2-cyclohexanediol, 1-phenylethylene glycol, and sulphate respectively

Complex peroxyuranates. Synthesis and structural assessment of alkali dioxoxperoxy(sulfato)aquouranates(VI), A<SUB>2</SUB>[UO<SUB>2</SUB>(O<SUB>2</SUB>)SO<SUB>4</SUB>(H<SUB>2</SUB>O)] (A = NH<SUB>4</SUB>, Na), and alkali dioxoperoxy(oxalato)uranate(VI) hydrates, A<SUB>2</SUB>[UO<SUB>2</SUB>(O<SUB>2</SUB>)C<SUB>2</SUB>O<SUB>4</SUB>].H<SUB>2</SUB>O

Yellow microcrystalline alkali-metal and ammonium dioxoperoxy(sulfato)aquouranates(VI), A2(UO2(O2)SO 4(H2O)) (A = NH4, Na), and alkali-metal and ammonium dioxoperoxy(oxalato)uranate(VI) hydrates, A2UO 2(O2)C2O).H2O (A = NH4, Na, K), have been synthesized from the reaction of the product obtained by treating an aqueous solution of UO2(NO3)2.6H2O with alkali-metal or ammonium hydroxide, AOH, with 30% H2O2 and aqueous sulfuric acid and oxalic acid solution, respectively, in the mole ratio UO2(NO3)2.6H2O:H2O2:SO42 - or C2O42- of 1:111:5 or 1, at pH 6 maintained by the addition of the corresponding alkali-metal or ammonium hydroxide. Precipitation was completed by the addition of ethanol. IR and laser Raman spectra suggest that the O22 - and SO42 - ions in (UO2(O2)SO4(H2O))2- are bonded to the UO22 + center in a bridging and in a monodentate manner, respectively, while both the O22 - and C2O42 - ions in (UO2(O2)C2O) 2 - bind the uranyl center in bidentate chelated fashion. The complex peroxyuranates are diamagnetic and insoluble. The A2(UO2(O2)SO4(H2O)) compounds, unlike A2(UO2(O2)C2O4).H2O, are stable up to 110&#176;C. Whereas H2O in A2(UO(O2SO4(H2O)) is coordinated to the UO22+ center, it occurs as a water of crystallization in the corresponding peroxy oxalato compounds

Synthesis and structural assessment of ammonium and caesium difluorodioxoperoxouranates(VI), A<SUB>2</SUB>[UO<SUB>2</SUB>(O<SUB>2</SUB>)F<SUB>2</SUB>](A = NH<SUB>4</SUB> or Cs), and alkali-metal difluorodioxoperoxouranate(VI) monohydrates,A<SUB>2</SUB>[UO<SUB>2</SUB>(O<SUB>2</SUB>)F<SUB>2</SUB>].H<SUB>2</SUB>O (A = K or Rb)

The product obtained by treating an aqueous solution of UO2(NO3)2.6H2O with NH4OH or KOH reacts with AF (A = NH4, Rb, or Cs) or KF, 30% H2O2, and a very small amount of 40% HF, in the mol ratio UO2(NO3)2.6H2O:AF:H2O2 of 1:4:110.8, at pH 6.5-7 to afford ammonium and caesium difluorodioxoperoxouranates(VI), A2[UO2(O2) F2](A = NH4 or Cs), and potassium and rubidium difluorodioxoperoxouranate(VI) monohydrates, A2[UO2(O2)F2].H2O (A = K or Rb). The i.r. spectra suggest that the peroxo-ligand is bonded to the UO22+ centre in a triangular bidentate (C2v,) manner

First synthesis and structural assessment of alkali-metal carbonatodioxoperoxouranate(VI) monohydrates, A<SUB>2</SUB>[UO<SUB>2</SUB>(O<SUB>2</SUB>)(CO<SUB>3</SUB>)].H<SUB>2</SUB>O, and carbonato-oxodiperoxovanadate(V) trihydrates, A<SUB>3</SUB>[VO(O<SUB>2</SUB>)<SUB>2</SUB>(CO3)].3H<SUB>2</SUB>O

The complexes A2[UO2(O2)(CO3)].H2O (A = Na or K) have been synthesised from the reaction of the product obtained by treating UO2(NO3)2.6H2O with AOH and AHCO3(ratio U : CO32-= 1:4) with an excess of 30% H2O2 at pH 7-8, and A3[VO(O2)2(CO3)].3H2O (A = Na or K) have been synthesised by treating V2O5 with A2CO3(ratio V: CO32-= 1 :1.5) and an excess of 30% H2O2 at pH ca. 7. They were precipitated with ethanol. The occurrence of trans OUO and terminal VO in the [UO2(O2)(CO3)]2- and [VO(O2)2(CO3)]3- ions, respectively, and the presence of triangular bidentate O22- and chelated bidentate CO32- groups, have been ascertained from i.r. and laser Raman spectra. The complexes A2[UO2(O2)(CO3)].H2O can be dehydrated at Ca. 100 &#176;C, a temperature at which A3[VO(O2)2(CO3)].3H2O starts to decompose