Spectral-luminescent properties of water-alcohol solutions of coumarin derivatives with additions of lithium chloride

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 54, No. 6, pp. 965–969, June, 1991.     

Voltammetric determination of selenosulfate ions at a mercury-film electrode

A procedure is proposed for the voltammetric determination of selenium as selenosulfate (SO₃Se^2?) ions at a mercury-film electrode (MFE). Selenosulfate ions are determined in the range from 2 × 10^?4 to 1.0 × 10^?3 M without analyte accumulation, using peak current at ?0.92 ± 0.02 V and in the range from 1 × 10^?7 to 2 × 10^?4 M after analyte accumulation with the open circuit, using peak current at ?1.18 ± 0.03 V as the analytical signal. The mechanisms of SO₃Se^2? reduction at an MFE under the conditions of direct voltammetry and stripping voltammetry with accumulation are proposed and discussed.     

Interaction in the ternary system HgBr<Subscript>2</Subscript>-PbBr<Subscript>2</Subscript>-CsBr

Several vertical sections are investigated in the HgBr₂-PbBr₂-CsBr system by the methods of physicochemical analysis. Six compounds, namely, CsHg₂Br₅, CsHgBr₃, Cs₂HgBr₄, CsPb₂Br₅, CsPbBr₃, and Cs₄PbBr₆, are formed in the bordering binaries of the ternary system. By the results of investigation, the projection of the liquidus surface of the HgBr₂-PbBr₂-CsBr system on the composition triangle is constructed, and the fields of primary crystallization of nine phases are plotted, namely, HgBr₂, PbBr₂, CsBr, CsHg₂Br₅, CsHgBr₃, Cs₂HgBr₄, CsPb₂Br₅, CsPbBr₃, and Cs₄PbBr₆. An immiscibility region is found in the system. This region occupies a considerable part of the primary crystallization field of PbBr₂. The coordinates of invariant points are determined, and isotherms are plotted.     

Interactions of aliphatic β-amino-β-trifluoromethylvinyl ketones with ethylenediamine

The reactions of aliphatic β-amino-β-trifluoromethylvinyl ketones with an excess of ethylenediamine at room temperature afforded the corresponding 2,3-dihydro-1H-1,4-diazepines or substituted 2-acetonyl-2-trifluoromethylimidazolidines (the latter were obtained when the approach to the carbonyl group was sterically hindered). Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2305–2308, November, 1998.     

Structure and Catalytic Properties of a Cu2+-Containing Hydrogel of Zirconium Dioxide

The distribution of Cu²⁺ ions in ZrO₂ and sulfated ZrO₂ hydrogel phases was studied by EPR spectroscopy and voltammetry. The formation of the following three types of copper structures was observed: mononuclear Cu²⁺ complexes (A), magnetic associates (B), and Cu²⁺ compounds (C) that gave no EPR signals under the conditions used in the spectroscopic measurements. The specific catalytic activity of various Cu²⁺ compounds in the liquid-phase reaction of 2,3,5-trimethyl-1,4-hydroquinone oxidation was determined. The copper complexes C were found to exhibit the highest catalytic activity.     

Partially Hydrolyzed Alkylaluminums as the Active Heterogenized Components of Metallocene Catalysts

The heterogenized reaction products of the partial hydrolysis of the organoaluminum compounds AlMe₃ and Al(i-Bu)₃ with water as a constituent of highly hydrated supports, zeolite (ZSM-5-H₂O) and montmorillonite (MMT-H₂O), have been synthesized. The thermal degradation of the resulting heterogenized methylalumoxane compound and methylalumoxane (MAO) in a solid state is studied by temperature-programmed desorption with the mass-spectrometric analysis of liberated gaseous products, and the structural identity of the above compounds is found. Alkylalumoxanes prepared immediately on the surface of a support form heterogenized complexes with the metallocenes Cp₂ZrCl₂ and Et(Ind)₂ZrCl₂. These heterogenized complexes exhibit high activity in the reactions of ethylene and propylene polymerization. For this reason, MAO can be replaced by AlMe₃ or Al(i-Bu)₃ and the additional introduction of MAO or another alkylaluminum for zirconocene activation is unnecessary. It has been found that, upon the immobilization of commercial MAO on dehydrated SiO₂, the MAO molecule loses a portion of its most reactive methyl groups and, as a result of this, becomes incapable of activating metallocenes.     

Electrochemical properties and state of paramagnetic centers in copper-modified complex vanadium and titanium oxides

Complex vanadium and titanium oxides modified by copper ions are studied by the electrochemical and ESR methods. Oxides Cu _x V_2?y Ti _y O_5?δ·nH₂O (0<y<1.33) have a layered structure and oxides Cu _x Ti_1?y V _y O_5+δ·nH₂O (0<y<0.25), an anatase structure. The intercalation of cations Cu²⁺ into the hydrates leads to oxidation of V⁴⁺. According to ESR data, V⁴⁺ exists in the oxides in the form of VO²⁺ and an octahedral surround of oxygen (V⁴⁺?O₆), respectively. The electroreduction of ions of d-elements and chemisorbed oxygen in the oxides is analyzed. The intercalation of cations Cu²⁺ alters the content of V⁴⁺ and the chemisorption ability of the oxides. Possible reasons for this phenomenon are discussed.     

Hydroxylamine derivatives

Conclusions Various O-substituted hydroxylamines were synthesized by the method proposed by us.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1820–1823, August, 1967.