Heterometallic nickel(II) samarium(III) diethylenetriaminepentaacetate, a starting material for the preparation of samarium nickelate films

A reaction of samarium oxide, nickel oxocarbonate, and diethylenetriaminepentaacetic acid (H₅DTPA) taken in stoichiometric proportions in water gave SmNiDTPA · 10H₂O as a glassy solid. The formation of this heterometallic complex was confirmed by data from elemental analysis, IR spectroscopy, thermal analysis, and X-ray fluorescence analysis. An aqueous solution of the complex was used to deposit SmNiO₃ films onto a single-crystal SrTiO₃(001) substrate. The SmNiO₃ phase in films obtained upon 3-h annealing at 500°C was identified by powder X-ray diffraction. Films deposited from a solution of an equimolar mixture of monometallic samarium and nickel diethylenetriaminepentaacetates contained no samarium nickelate.     

N,N′-bis(2-Vinyloxyethyl)carbodiimide

Previously unreported N,N-bis(2-vlnyloxyethyl)carbodiimide was synthesized by the reaction of N,N -bis(2-vinyloxyethyl)thiourea with yellow mercuric oxide in CH₂Cl₂ at room temperature.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1897–1898, August, 1990.     

Air-gap sulfide sensor with super-nernstian response in the low concentration range

An air-gap sulfide sensor is presented which operates on the basis of selective extraction of H₂S from an acidified sample into a small alkaline electrolyte film containing the dicyanoargentate (I) complex. This complex is partly decomposed during the measurement by the absorbed sulfide, and the potential of a silver sulfide-based indicator electrode which is in direct contact only with the electrolyte, then depends on the sulfide concentration of the sample. Because of the extraction and dissociation equilibria, the sensor responds in the low sulfide concentration range with a slope four times larger than that of a normal sulfide electrode. The lower limit of linearity is 10^?8 mol l^?1, because sulfide accumulates in the electrolyte film.     

Polymerisation cationique de l'indene amorcee par le tetrachlorure de titane-I Influence des impuretes du solvant,le chlorure de methylene,et effets cocatalytiques de l'eau et de l'acide chlorhydrique

The polymerization of the system indene-titanium tetrachloride-methylene chloride gave irreproducible kinetics which have been attributed to variable concentrations of impurities in the solvent. Incomplete yields sometimes observed at ?70° are also caused by impurities, but introduction of water and hydrochloric acid then gives complete yields. A new method of solvent purification has been used giving reproducible yields and rates. In such cases, monomer consumption at ?70° follows the rate law log [M]_o/[M] = kt.     

The influence of solute-solvent interactions on the kinetics and stereospecificity of polymerization-the relevance of aromatic solvent shifts observed on the nmr spectrum of methyl methacrylate

The effect of certain aromatic compounds on the PMR spectrum of methyl methacrylate (MMA) was investigated. The magnitude of observed aromatic-induced shifts decreased in the order benzene ? styrene > chlorobenzene ≈ bromobenzene.Assuming that the interaction arises from a stoichiometric 1:1 complex, equilibrium parameters for the MMA-benzene interaction have been estimated. ΔH ± S.E. (ΔH) = ?(8 ± 4) kJ mol^?1. These effects are likely to have a small influence on the kinetics of copolymerization with aromatic monomers and polymerization in aromatic solvent. The stereochemistry of the solute-solvent interactions suggests that MMA takes a cis-conformation in solution, which is relevant to the mechanism of stereoregular polymerizations of this monomer.     

Floating spherical gaussian orbital (FSGO) studies with a model potential: some open-shell systems

A gaussian based model potential is used within the FSGO formalism to study a series of open-shell systems (e.g. LiH⁺, NaH⁺, Li⁺₂ and LiNa⁺). Results for calculated equilibrium geometries and dissociation energies are compared to the corresponding quantities from available all-electron ab initio studies and other more elaborate theoretical estimates. The overall agreement is quite satisfactory.     

Kinetic Salt Effect in the 18O-Exchange Reaction between Bromate and Water

The kinetic salt effect in the ¹⁸O-exchange reaction between bromate ion and water has been investigated at 60° in a range of ionic strength from 0.02M < I < 1.9M using NaNO₃ or NaClO₄ as inert salts. From the experimental data the following relation was deduced for the uncatalysed reaction path In the H⁺-catalysed reaction path the Brønsted-Davies equation was obeyed up to I ? 0.1M At I > 0.8M the sign of Δ logk₂/Δ I^1/2 was positive. The theoretical interpretation of these results is consistent with the mechanistic evidence obtained previously from the rate law and the solvent isotope effects.     

The gas chromatography, thermal analysis and mass spectrometry of fluorinated lead β-diketonates Determination of traces of lead by the integrated ion-current technique

Preparative details for perfluoroalkanoylpivalylmethanes and their lead chelates are given. Thermal analysis, gas chromatography and mass spectral studies all indicate high thermal stability, but strong column interaction makes successful quantitative gas chromatography difficult. The integrated ion-current technique is applied to determine lead heptafluorobutanoylpivalylmethanate in the range 10^-9–10^-7 g of lead, but a lower detection limit of ca. 10^-14 g is indicated.