Synthesis of pentanuclear linear compounds with chainlets of Os3-Sn-M bonds (M = W,Re, or Fe)

Conclusions By reacting the Na derivatives of metal carbonyls with l-chloro-3-trichlorostannyldodecacarbonyltriosmium ClOs₃(CO)₁₂SnCl₃ we were the first to obtain pentanuclear linear compounds that contain a fragment composed of three osmium atoms in the metal chain.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2790–2792, December, 1981.     

Covalent nature of the metal-halogen bonds in trinuclear osmium carbonyl halides

Comparison of the results of the electrochemical reduction of trinuclear osmium carbonyl halides with linear structure, Os₃(CO)₁₂X₂, and nonlinear structure, Os₃(CO)₁₀(-X)₂ (X=I, Br, and Cl) with mononuclear carbonyl halides of transition metals indicates covalent nature of the metal-halogen bonds in these compounds. Chemical dissociation does not occur upon dissolving the trinuclear osmium carbonyl halides in acetonitrile and the cleavage of the Os-X bonds is a result of the electrochemical reduction. The observed order for ease of reduction of the trinuclear osmium carbonyl halides coincides with the change in the E_1/2 values in the reduction of the mononuclear carbonyl halides of transition metals and alkyl halides.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 459–460, February, 1990.     

Electrochemical Reduction of Palladium-containing Heteronuclear Complexes

Reduction of a series of palladium-containing complexes with MnPd, Fe2Pd, and Fe3Pd skeletons was studied by classical polarography, cyclic voltammetry, and controlled-potential electrolysis in acetonitrile. The electrochemical behavior of these complexes was compared to that of relared platinum complexes.     

Framed aromatic polyurethanes based on an anionic macroinitiator, 4,4'-diphenylmethane diisocyanate,and 4,4'-dihydroxy-2,2-diphenylpropane: Metal-complex modification

Metal complexes are prepared from poly(oxyethylene glycol) and iron(III) chloride and studied as modifiers of framed aromatic polyurethanes. The latter polymers are synthesized on the basis of macroinitiators, 4,4'-dihydroxy-2,2-diphenylpropane, and polyisocyanate, which is a mixture of 4,4'-diphenylmethane diisocyanate and its branched derivatives. The interaction of iron(III) chloride with poly(oxyethylene glycol) is accompanied by redox processes that lead to its degradation and partial reduction of Fe(III) to Fe(II). Aromatic polyurethanes are modified in the concentration range of metal complexes from 0.5 to 20%. At a concentration of metal complexes of 4–7%, the polymer shows high mechanical characteristics and excellent thermal stability. The framed structure of aromatic polyurethanes hampers the effective contacts of coordinately bonded Fe atoms that are present in various oxidation states.     

Transition metal catalyzed Fe–C coupling reactions in synthesis of dicarbonyl(2-thienylethynyl)(η5-cyclopentadienyl)iron complex: Spectroscopic,structure and electrochemical study

Transition Metal Chemistry - The new σ-alkynyl iron(II) complex Cp(CO)2Fe-C≡C-(2-C4H3S) was synthesized with application of several known approaches based on the transition metal...     

System peaks in capillary zone electrophoresis of anions with negative voltage polarity and counter-electroosmotic flow

The system peaks that often appear on electropherograms in anion separation by CE with indirect spectrophotometric detection, negative voltage polarity and cathodic EOF are studied. The system peaks are shown to correspond to the zones with the changed concentration of the BGE constituents; they appear while the zone of each analyte anion passes through the outlet end of the capillary and are transported to the detector by EOF. An equation is suggested for predicting migration times of the system peaks with an error of 1%. The ratios of the system peak area to the analyte peak area are found to amount to 20%. It is shown that it is possible to avoid overlapping of the system peaks and analyte peaks by controlling the EOF velocity owing to hydrodynamic pressure. Using the mathematical simulation of CE shows that the system peaks and baseline shift can result from changing the transference numbers of the BGE ions and analyte ions at the capillary edge. The cases when the system peak may be incorrectly identified as the peak of analyte ion are considered. In order to avoid such errors, some practical recommendations are given.     

Synthesis, IR and NMR characterization and ion extraction properties of tetranonylcalix[4]resorcinol bearing acetylhydrazone groups

A series of new calix[4]resorcinarenes (rccc-isomer) and resorcinols functionalized by acetylhydrazone binding fragments have been synthesized. The IR and NMR data and stereochemical behaviour of hydrazones are reported and compared with the results of earlier investigations. The barriers of rotation of hydrazone fragments for some octahydrazone derivatives of calix[4]resorcinarenes and their resorcinol analogues have been determined by NMR-measurements. The complexing behaviour of bis- and octahydrazones has been studied by liquid-liquid extraction towards the s-metal ions (Li⁺, Na⁺, K⁺, Cs⁺ and Ca²⁺), p-metal ions (Pb²⁺), d-metal ions (Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺ and Hg²⁺) and f-metal ions (La³⁺, Gd³⁺ and Lu³⁺). The stoichiometry of complexes and the extraction constants have been determined. It has been established that octahydrazones do not extract alkali metal cations but show excellent selectivity towards transition and soft heavy metal cations (especially Hg²⁺ or Pb²⁺).