Soumitra K. Ghosh

Synthesis of alkali oxydiperoxyfluorovanadates(V)

Abstract The reaction of vanadium pentoxide with hydrogen peroxide in an alkaline medium in the presence of alkali fluorides AF (A = NH 4 , Na, K, Rb or Cs) g

Direct synthesis of bis(acetylacetonato)nickel(II) dihydrate and isolation of α,α,β,β-tetra-acetylethane as the oxidation product of acetylacetone

NiO(OH) undergoes a facile reaction with acetylacetone affording a very high yield of bis(acetylacetonato)nickel(II) dihydrate, [Ni(acac)2]·2H2O, and giving α,α,β,β-tetra-acetylethane as the oxidation product of acetylacetone.

Synthesis of alkali oxytetrafluorovanadates(V)

Abstract I.R. and 19F N.m.r. spectroscopy, molar conductance, magnetic moments and chemical analyses show that alkali oxytetrafluorovanadates(V), AI[VOF 4], are the principal products of the reactions of V2O5 with 40% HF and alkali bifluorides AIHF2 in presence of a small amount of alcohol at steam bath temperature. While the i.r. spectra suggest square pyramidal C4v structures for solid AI[VOF4], the 19F N.m.r. spectrum shows stereochemical non-rigidity owing to rapid fluorine rearrangement between C4v and the trigonal bipyramidal C2v stereochemistry of [VOF4]− in solution.

The first reported syntheses and characterisation of alkali metal trifluoronickelate(II) monohydrates, MNiF3 · H2O (M = NH4, Na or K)

SummaryNi(acac)2 · (H2O)2 (1 mol) and alkali metal fluorides (4 mols), MF (M=NH4, Na or K), react with an excess of 40% HF on a steam-bath. The product upon treatment with water gives light green crystalline alkali metal trifluoronickelate(II) monohydrate, MNiF3 · H2O in a high yield. Chemical analyses, pyrolysis at 120 °C, i.r. spectroscopic, and cryomagnetic (300–80 K) data have been used to characterise, and establish the identity of the compounds. While NH4NiF3 · H2O behaves as a normal octahedral nickel(II) compound, NaNiF3 · H2O is ferromagnetic with Curie point 145 K, KNiF3 · H2O behaves antiferromagnetically; its Neel point is 230 K.

Notes. Novel synthesis of tris(acetylacetonato)iron(III)

The reaction of iron(III) hydroxide with acetylacetone, in the absence of any buffer, readily gives highly crystalline tris(acetylacetonato)iron(III), [Fe(acac)3], in very high yield. Its mass spectrum provides evidence for rearrangement to give Fe–CH3species.

Synthesis of tetrafluoronickelate(II) and tetrafluorozincate(II) complexes from aqueous media: a novel route to fluorometalates

The complexes A2[NiF4](A = NH4+, K+, or Rb+) and A2[ZnF4](A = NH4+, K+, Rb+, or Cs+) have been synthesised, from the corresponding metal acetylacetonates (acac) with 40% HF and AF, in very high yields. The new method also allows the preparation of [VOF5]2–, [MnF5]2–, and [CrF5(H2O)]2– from [VO(acac)2], [Mn(acac)3], and [Cr(acac)3] respectively.

Synthesis of alkali-metal diaquafluoro-oxoperoxovanadate(IV) complexes [VO(O2)F(H2O)2]–

Orange-red alkali metal diaquafluoro-oxoperoxovanadates(IV), A[VO(O2)F(H2O)2](A = NH4, K, Rb, or Cs), have been synthesised by the reaction of A[VOF4] with H2O2 in the molar ratio 1 : 12 followed by precipitation with ethanol. Characterisation of the compounds was made from the results of chemical analyses, chemical determination of oxidation state of vanadium, i.r. and electronic spectroscopic studies, and magnetic susceptibility measurements. I.r. spectra suggest that the peroxo-ligand is bonded to the V4+ centre in a triangular bidentate fashion.