1,2-Dibenzoyl- and 1-benzoyl-2-acetylhydrazines as reagents for recovering Cu(II) ions from alkaline solutions

The conditions of complexation of 1,2-diacylhydrazines (H₂L) C₆H₅C(O)NHNHC(O)R, where R = C₆H₅ or CH₃, with Cu(II) ions in alkaline solutions were studied. The composition of the complexes formed by precipitation of Cu(II) from alkaline solutions, (CuOH)₂L and CuL, was determined. The possibility of afterpurification of solutions with a low Cu(II) content by pneumatic flotation using H₂L was examined.     

Isomerization and conformational transformations of theN-allyl-N-methylcarbamoyl bridging ligand in the (μ-H)Os3{μ-OCN(Me)CH2CH=CH2}(CO)10 complex

The (μ-H)Os₃{μ-OCN(Me)CH₂CH=CH₂}(CO)₁₀ complex containing an allylic fragment in theN,N-dialkylsubstituted carbamoyl briding ligand was synthesized. The stereo-chemical behavior of this complex in solution was investigated. As follows from the NMR spectral data, the complex undergoes reversible conformational (about the amide C−N bond) and irreversible allylic isomerization. Both conformers were isolated in the solid state by chromatography at a reduced temperature. The allylic isomerization occurs stereospecifically to produce the (μ-H)Os₃{μ-OCN(Me)CH=CHMe}(CO)₁₀ complex with thetrans-oriented olefinic hydrogen atoms. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 158–162, January, 1998.     

Sorption–Optical Determination of Nitrite Ions in Sea Water with Chromotrope 2B

The Chromotrope 2B reagent was used as an analytical reagent for the direct determination of nitrite ions by sorption chromaticity measurements, diffuse reflectance spectrometry, and solid-phase spectrophotometry. The silochrom C-120 silica gel and the AV-17 anion exchanger were used as supports. Optimum conditions were found for the formation and sorption of Chromotrope 2B. The dependence of the chromaticity characteristics (chromaticity coordinates, lightness, color saturation, yellowness, and whiteness) on the concentration of nitrite ions was examined. The advantages of the use of chromaticity characteristics over the diffuse reflection coefficient were demonstrated. A procedure was developed for the test and sorption–optical determination of nitrite ions in sea water.     

Optical and chromaticity characteristics of cobalt 1-nitroso-2-naphthol-3,6-disulfonates

The optimum conditions of the complexation of cobalt with nitroso-R salt in the presence of and without ascorbic acid were found. Molar coefficients of chromaticity functions of the complexes were calculated, and it was demonstrated that cobalt(II) and cobalt(III) complexes can be distinguished only with the use of chromaticity functions, whereas their optical characteristics are nearly the same. For practical purposes, it is better to introduce ascorbic acid and to obtain the kinetically inert complex of cobalt(III) with nitroso-R salt.     

Hydroperoxide Oxidation of Difficult-to-Oxidize Substrates: An Unprecedented C–C Bond Cleavage in Alkanes and the Oxidation of Molecular Nitrogen

In the V^(V)H₂O₂/AcOH system, C₅–C₂₀ n-alkanes, isooctane, and neohexane undergo oxidation to ketones and alcohols; the oxidation products of branched alkanes are indicative of a C–C bond cleavage in these substrates. A concept is developed, according to which the peroxo complexes of vanadium(V) are responsible for alkane oxidation. These complexes can transfer the oxygen atom or the O^+· radical cation to a substrate. The formation of nitrous oxide was found in the oxidation of molecular nitrogen in the H₂O₂/V^(V)/CF₃COOH system.