Electrodeposition of a cobalt-molybdenum alloy from an ammonia-citrate electrolyte

Kinetics of processes of electrochemical production of a cobalt-molybdenum alloy out of an ammonia-citrate electrolyte is studied. The electrolyte’s composition is similar to that used for depositing a nickel-molybdenum alloy. It is established that the cobalt-molybdenum alloy undergoes deposition at smaller values of pH (5.0–6.0) than the nickel-molybdenum alloy (7.0–9.0). The current efficiency for the cobalt-molybdenum alloy is substantially dependent on the electrolyte pH, whereas the chemical composition of the obtained deposits is practically independent of the electrolyte pH in the pH interval 5.0–8.0 at current densities of 0.025 to 0.100 A cm^?2. On the other hand, a change in the electrolyte pH produces a considerable effect on the morphology of the obtained deposits. At large values of pH (pH 8.0), one can obtain a powder-like deposit of the cobalt-molybdenum alloy with a small value of the current efficiency. The deposits that are obtained in the pH region 5.0–6.0 have some cracks, with the number of cracks increasing with the electrolyte pH.     

On the mechanism of vanillin formation in the catalytic oxidation of lignin with oxygen

The influence of catalyst (CuSO₄ solution), pH and temperature on the vanillin formation and oxygen consumption in oxidation of lignin in alkaline media have been studied. It was shown that the main role of catalyst in the lignin oxidation is to change the selectivity of hydroperoxide fragmentation rather than to accelerate oxidation.     

Bioaccumulation study of acrylates in algae (<Emphasis Type="Italic">Chlorella kessleri</Emphasis>) by Py-GC and Py-GC/MS

Acrylate monomers methylmethacrylate (MMA) and cyclohexylmethacrylate (CHMA) bioaccumulation has been determined in aquatic organism, algae (Chlorella kessleri). Algae were collected in amount of 0.4 mg and directly injected to the pyrolytical cell. In algae bodies accumulated monomers were analysed by pyrolysis gas chromatography (Py-GC) and pyrolysis gas chromatography coupled with mass spectrometry (Py-GC/MS). Traces of the accumulated monomers in algae body can be determined after 1-, 2-, 3-weeks of incubation. Maximum content of MMA was determined after 3-week of experiment, contrariwise in the case of CHMA after 2-week exposition. Relationship with pyrolysis temperature has also been studied.     

Energetic aspects in description of metal—hydrogen—boron bonds in (B<Subscript>10</Subscript>H<Subscript>14</Subscript>)<Subscript>2</Subscript>Pt and (B<Subscript>8</Subscript>C<Subscript>12</Subscript>H<Subscript>14</Subscript>)<Subscript>2</Subscript>Pt complexes

The energies of formation of platinum complexes with borohydrides B₁₀H₁₄ and B₁₀H ₁₄ ^2- or carboranes B₈C₂H₁₄ and B₈C₂H ₁₄ ^2- were considered in terms of the structure—thermodynamics model. The thermodynamic stability of these complexes was substantiated.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 2, 2005, pp. 149–152. Original Russian Text Copyright © 2005 by Ionov, Kuznetsov.     

Synthesis of new macrocyclic aminomethylphosphines based on 4,4"-diaminodiphenylmethane and its derivatives

The reaction of bis(hydroxymethyl)phenylphosphine with 4,4"-diaminodiphenylmethane in DMF afforded 1,1",5,5"-bis[methylenedi(p-phenylene)]di(3,7-diphenyl-1,5-diaza-3,7-diphosphacyclooctane) (1) whose structure was established by X-ray diffraction analysis. Sulfurization and oxidation of macrocyclic tetraphosphine 1 gave rise to products 2 and 3, respectively, compound 3 being obtained as a stable hexahydrate. The reaction of bis(hydroxymethyl)phenylphosphine with bis(4-N-methylaminophenyl)methane in DMF followed by sulfurization yielded monocyclic bis{methylenedi[p-phenylene(N-methyl)aminomethyl]}di(P-phenyl)phosphine sulfide (4).     

Temperature dependence of nqr spectra in MSbBrF3 (M=Na,Cs, NH4) and Cs3Sb2Br9

Conclusions We have studied the temperature dependence of the NQR parameters of¹²³Sb and⁸¹Br in the range 77–360 K for the complexes of MSbBrF₃ (M=Na, Cs, NH₄) and Cs₃Sb₂Br₉. We have established the temperature regions for which piezoelectric properties appear in the crystal hydrate NaSbBrF₃.H₂O, and in the compounds MSbBrF₃ (M=Na, NH₄) and Cs₃Sb₂Br₉ anomalous changes appear in the dependences of the quadrupole coupling constant, the asymmetry parameter of the electric field gradient for the antimony atoms and the resonance frequency of the bromine atoms.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1501–1504, July, 1987.     

Heterocycles from amino acids. A novel synthetic approach for imidazo[1,5-a]pyridines and imidazo[1,5-a]quinolines

From the corresponding heterocyclic amino acids 2 and 9a the heterocyclic systems imidazo[1,5-a]pyridine ( 3 ) and imidazo[1,5-a]quinoline ( 10 ) are easily accessible. From compound 7 the tricyclic system 11 was prepared and from compound 17a a pyridyl-1,2,4-triazinone ( 18 ) could be obtained.     

Dissociative ionization of substituted piperideines

The fragmentation of different alkyl(aryl) substituted piperideines [tetrahydro-pyridines] was studied by analyzing high-resolution mass spectra and DADI [Direct Analysis of Daughter Ions] spectra. It was shown that the retrodiene decomposition of the ring is suppressed by competing processes of elimination of ring substitutents. The nature of the substituents and their mutual disposition on the ring have a substantial influence on the extent of their cleavage from the ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 795–800, June, 1988.     

Ab initio crystal orbital studies on linear chains of H atoms

Anab initio crystal orbital method is used to calculate the energies of an infinite chain of H atoms and of linear arrangements of H₂ molecules with different interatomic distances. The H₂ arrangements are not stable in respect to isolated molecules. The cohesive energy of an optimized arrangement of H atoms chain is 0.0354 a.u.     

Reactions of quaternized imidazo-quinazoline and-pyridopyrimidine with active methylene compounds

Summary Syntheses of 1-methylimidazo[1,2-c]quinazolinium iodide (3) and 1-methylimidazo[2,1-f]pyrido[3,2-d]pyrimidinium iodide (4) are described. These tricyclic compounds react with nucleophiles derived from active methylene compounds to give the corresponding open-chain enamines.

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Reaktionen von quaternisierten Imidazo-Chinazolinen und -Pyridopyrimidinen mit Verbindungen mit reaktiven Methylengruppen

Zusammenfassung Synthesen von 1-Methylimidazo[1,2-c]chinazoliniumjodid (3) und 1-Methylimidazo[2,1-f]pyrido[3,2-d]pyrimidiniumjodid (4) werden beschrieben. Diese tricyclischen Verbindungen reagieren mit einigen Carbanionen aus Verbindungen mit reaktiven Methylengruppen, wobei die offenkettigen Enamine entstehen.