Tungsten oxide bronzes with alkali metals

Single-phase samples of tungsten bronzes M _x WO₃ (M = K⁺, Rb⁺, Cs⁺) are prepared by solid-state synthesis. The reversibility of the M_0.33WO₃/M⁺-solid electrolyte interface is studied subject to the alkali metal nature and humidity over a wide temperature interval. The exchange current density at 24°C and 58%-relative humidity is 3.6 × 10^?4 A/cm² for the Rb_0.33WO₃/Rb⁺-solid electrolyte interface; 2.2 × 10^?4 A/cm² for the Cs_0.33WO₃/Cs⁺-solid electrolyte interface; and 1.3 × 10^?4 A/cm² for the K_0.33WO₃/K⁺-solid electrolyte interface. A correlation between the reversibility of the bronze|solid electrolyte interface, which is characterized by the exchange current density, and the rate of potential equilibration in sensor systems, where the bronze is a reference electrode, is revealed. Ionic component of the conductivity of the synthesized tungsten oxide bronzes is measured at a background of the predominant electronic conductivity. The ionic conductivity is three orders of magnitude lower than the electronic conductivity; it decreases in the series Rb_0.33WO₃ > Cs_0.33WO₃ > K_0.33WO₃, amounting to 2.3 × 10^?2, 2.1 × 10^?3, and 2 × 10^?4 S cm^?1, respectively. The working capacity of the M_0.3WO₃ bronzes as reference electrodes in sensor systems for carbon dioxide detection is evaluated. The plots of the cell potential vs. the CO₂ concentration in the electrochemical cells are linear, their slopes (59 ± 1 mV/decade) are characteristic for one-electron process. The fastest response to changes in the CO₂ concentration was obtained with the sensor system that used Rb_0.33WO₃ as reference electrode.     

Coordination compounds of hydrazine derivatives with transition metals. Part 22. Reaction of aroylhydrazones with copper(II) salts

Summary Two different crystalline forms namely the greenanti and the brownsyn were isolated from the reaction of copper(II) acetate with some aldehydic aroylhydrazones, while others gave only the brown form. With copper(II) chloride, however, reduction of copper(II) ions occurred and copper(I) chelates of general formula Cu(HL)Cl were obtained. Tridentate ligands such as salicylaldehyde and pyridine-2-carbaldehyde aroylhydrazones gave copper(II) chelates Cu(L)Cl₂. A tentative reduction mechanism involving intramolecular electron transfer was proposed. In such a mechanism the steric requirements of the aroylhydrazone molecule and the presence of a third coordination site would stabilize the dipositive oxidation state of copper.     

Coordination compounds of hydrazine derivatives with transition metals. Part 24. Coordination chemistry of hydrazine-S-methyl carbodithioate schiff bases derived from β-dicarbonyl compounds

Summary The reactions of -diketones and -ketoaldehydes with hydrazine-S-methyl carbodithioate, hydth, have been studied in the absence and presence of metal(II) ions. A series of dimeric monoligand chelates [Ni(-dikhydth-2H)]₂ have been isolated. The reaction of these chelates with monodentate Lewis bases yields square planar [Ni(-dikhydth2H)B] chelates. Bisligand chelates of benzoylacetone monohydrazones [M(Bzachydth-H)₂] (M=Cu or Zn) have been also synthesized, as have a series of Ni^II and Zn^II chelates of -diketone bishydrazones of the type [M(-dik(hydth)₂-2H)].     

Coordination compounds of hydrazine derivatives with transition metals. Part 21. Reaction of 1,5-thiocarbodihydrazones with nickel(II) and copper(II) salts

Summary A series of 1,5-thiocarhodihydrazones (HL) were reacted with nickel(II) acetate to give neutral bisligand nickel(II) chelates, Ni(L)₂. Reaction of nickel(H) chloride, however. results in partial hydrolysis of the dihydrazones to give Ni(RCH=NNHCSNHNH₂)₂Cl₂ chelate complexes. Deprotonation of these chelates with pyridine gave the neutral chelates Ni(RCH=NN=CSNHNH₂)₂. Copper(H) salts are readily reduced by the dihydrazone ligands to copper(I) chelates of the type CuL, Cu(HL)₂CI and Cu₂(HL)₃CI₂.     

Coordination compounds of 3d metals malonates and glutarates with thiosemicarbazide

Complexes of copper(II), nickel(II), and cobalt(III) malonates and glutarates with thiosemicarbazide have been prepared and studied by means of elemental analysis, IR spectroscopy, diffuse reflection spectroscopy, and thermogravimetry.     

Microdetermination of carbon in compounds containing alkali metals

Zusammenfassung Wenn organische Verbindungen außer Alkalimetallen auch noch eine zumindest äquivalente Menge Schwefel enthalten, so besteht der Verbrennungsrückstand aus Alkalisulfat. Auf Grund dieser Beobachtung wird darauf hingewiesen, daß sich außer Kaliumdichromat und Vanadiumpentoxyd auch Kaliumpersulfat als oxydierender Zusatz zur organischen Substanz für die Verdrängung des Kohlendioxyds aus der Asche eignet.

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Résumé Quand des composés organiques, outre les métaux alcalins contiennent encore une quantité au moins équivalente de soufre, le résidu de la combustion apparaît sous la forme de sulfate alcalin. Sur la base de cette observation, on a montré, qu'à côté du bichromate de potassium et de l'anhydride vanadique, le persulfate de potassium convenait comme oxydant de la substance organique et pour débarrasser les cendres de l'anhydride carbonique.

     

Coordination compounds of hydrazine derivatives with transition metals. Part 26. Coordination properties of α-diketone and α-ketoaldehyde bishydrazones derived from hydrazine-S-methylcarbodithioate

Summary Metal(II) chelates with -diketone and -ketoaldehyde bishydrazones derived from hydrazine-S-methylcarbodithioate with the general formula M[-dik(hydth)₂-2H] (M=Zn^II, Cd^II, Ni^II, Cu and Pd^II) were prepared and characterized by i.r., electronic and mass spectra as well as magnetic properties. The Ni^II, Zn^II and Cd^II chelates are most probably pentacoordinated dimers whereas the Cu^II chelates are polymeric through Cu-S linkages. The Pd^II chelates are square planar monomers.     

Calixarenes functionalized with phosphine oxide and diamide functions as extractants and ionofores for rare-earth metals

Calixarene-based ligands with phosphine oxide and diamide functions at wide and narrow rims are synthesized and studied as extracting agents for liquid extraction and ionophores for polymeric electrochemical ion sensors. Calixarene ligands are compared with corresponding phosphine oxide and diamide ligands which are not attached to the calixarene platform. Extraction and sensor properties of the ligands were studied in different metal ion solution with special attention paid to rare-earth metals. Attachment of phosphine oxide groups to the calixarene platform leads to the sharp increase of both extraction and sensing ability of the corresponding systems comparing to non-bonded phosphine oxide. In case of the diamide derivatives attached to the calixarene performance of corresponding ligands was similar to those of non-bonded diamides.     

Electronic structures and geometrical parameters of simple methyl derivatives of hydroxylamine,phosphine oxide,and phosphine sulfide

Mendeleev Moscow Chemical Engineering Institute and Baikov Metallurgy Institute, Russian Academy of Sciences. Translated from Zhurnal Strukturnoi Khimii, Vol. 33, No. 5, pp. 28–36, September–October, 1992.     

Multinuclear NMR structural study of novel γ-iminophosphonate and phosphine oxide derivatives

Journal of Structural Chemistry - We report for the first time the synthesis of γ-iminophosphonates and phosphine oxides from the acid-catalysed reaction of primary amines with...     

Magnetic properties of quasi-one-dimensional copper oxide compounds

The results from theoretical and experimental studies of the magnetic properties of quasi-one-dimensional compounds consisting of molecular chains with magnetic ions are discussed. Along with traditional systems with antiferromagnetic exchange interaction of the nearest magnetic ions in a chain, a class of recently synthesized cuprates with frustrating (competing) ferro- and antiferromagnetic interactions is considered. Attention is focused on the properties of the ground state and low-temperature thermodynamics of these cuprates, depending on the frustration parameter.     

Magnetic effects in the reaction of benzyl chloride with triethylgermyl derivatives of alkali metals

The reaction of benzyl chloride with triethylgermyllithium and its analogs have been studied by the¹H-CIDNP method. A reaction mechanism is suggested. Benzyl and triethylgermyl free radicals have been found to be the precursors of main products. The magnetic field effects on the ratio of the main reaction products indicate that the radical path of their formation is predominant. The assumption is made that the ethylgermyl radicals take part in the reaction in the associated state.

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¹H . . , . , . , .

     

Synthesis of copper(II) coordination compounds with benzoxazine derivatives

Copper(II) complexes with 1,2-dihydro-4H-3,1-benzoxazine (HL) derivatives, CuLOH, were prepared by anodic electrosynthesis. The use of an amalgamated copper anode resulted in an increase in the electrosynthesis rate. It follows from the IR spectra of the products that the benzoxazine ring in the ligand molecule is opened upon complexation, while a six-membered chelate ring involving the oxygen atom of the deprotonated phenol group and the imine nitrogen atom is formed.     

Coordination compounds of copper with 2-formylpyridine 4-(dimethylphenyl)thiosemicarbazones

2-Formylpyridine 4-(2,6-dimethylphenyl)-(HL¹), 4-(2,5-dimethylphenyl)-(HL²), 4-(3,4-dimethylphenyl)-(HL³), and 4-(2,4-dimethylphenyl)thiosemicarbazones (HL⁴) react with copper chloride and nitrate to form coordination compounds CuL^1–4X·nH₂O [X = Cl^?, NO ₃ ^? ; n = 1, 2]. All compounds have a polynuclear structure. Azomethines HL^1–4 act as the bridging monodeprotonated tridentate N,N,S-ligands. The thermolysis of the complexes includes the dehydration (70–90°C) and total thermal decomposition (350–520°C). The complexes synthesized exhibit a selective antimicrobial activity against a series of standard strains of Staphylococcus aureus and Escherichia coli in the concentration range of 0.009–37.5 μg ml^?1.     

Reduction of aromatic nitro compounds with phosphine

The reduction of 1- and 2-nitronaphthalene and of some mono- and dinitro-biphenyls with phosphine was carried out under the conditions described by Buckler.¹ Reduction of 1-nitro-naphthalene did not yield any crystalline product while reduction of 2-nitronaphthalene yielded benzo[f]naphtho[2,1-c]cinnoline-N-oxide together with 2,2′-azoxynaphthalene. The mononitro-biphenyls and 4,4′-dinitrobiphenyl were readily reduced to azoxy compounds, while reduction of 2,2′-dinitrobiphenyl gave benzo[c]cinnoline-N,N′-dioxide.