Preparation of cyclopentadienes and diazocyclopentadienesvia cyclopentenolones and cyclopentenones

The structure and stereochemistry of the cyclopentenolones obtained by condensation of dialkyl ketones with benzil have been studied by NMR spectroscopy. These enolones were converted into cyclopentenones and cyclopentadienes. Alkyl-substituted cyclopentadienes required phenyllithium to effect their conversion by toluenesulphonyl azide into diazo-cyclopentadienes; otherwise piperidine sufficed as base catalyst.2,3,4-Triphenyldiazocyclopentadiene was simply procured by reaction of the condensation product of benzil and phenylacetone with toluenesulphonylhydrazone followed by alkali. Cyclohexyl- and methoxy-triphenylcyclopentadienes were prepared by photolytic decomposition of diazotriphenylcyclopentadiene in cyclohexane or methanol respectively.     

Synthesis and spatial structure of the geometrical isomers of 4-substituted 1-tert-butyl-3-methyl-piperidin-4-ols and 4-acyloxy-1-tert-butyl-3-methylpiperidines

In order to study the interrelationship between the structure, reactivity, and spectroscopic characteristics of the stereoisomeric piperidines, starting from 1-tert-butyl-3-methylpiperidin-4-one the synthesis has been performed of the geometric isomers of some 4-substituted 1-tert-butyl-3-methylpiperidin-4-ols and 4-acyloxy-1-tert-butyl-3-methylpiperidines. The spatial structures of the compounds obtained have been determined by IR and PMR spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1056–1061, August, 1973.     

Metastable anions of CO2

Long-lived metastable negative ions of CO₂ have been observed in the gas phase as direct products of electron and cesium collisions with organic molecules which contain “bent” CO₂ as a basic unit. The long autodetachment life-times are attributed to two related factors - first, the potential energy curve of CO⁻₂(²A₁) lies below that of CO₂(¹A₁) at 134°, and, second, an unfavorable Franck-Condon overlap exists between the bent ion (134°) and the linear neutral parent.     

Coordination compounds of indium : XIV. The insertion of indium(I) iodide into carbon-iodide bonds

Alkylindium(III) diiodides can be conveniently prepared in high yield by the insertion of indium(I) iodide into the CI bond of alkyl iodides. The products are halogen-bridged neutral dimers, except for the methyl compound, which is believed to be [(CH₃)₂In][InI₄ in the solid state. One of the intermediates isolated from the reaction mixture is (CH₃)₂InI₂INI(CH₃); the vibrational spectrum of this compound, and of (CH₃IInI₂INI₂, have been investigated. The mechanism of the initial reaction, and the subsequent rearrangement processes, are discussed.     

Conductance studies in amide-water mixtures. II. Sodium salts inN,N-dimethylformamide-water mixtures at 35°C

Conductance data for sodium nitrite, chloride, and acetate in water andN,N-dimethylformamide (DMF)-water mixtures (74.82D42.48) for the concentration range 0.001–0.04N, as well as the densities, viscosities, and dielectric constants of the solvent mixtures at 35°C, are reported. The data have been analyzed by the Fuoss (1975) equation. The existence of a maximum in the viscosity at a 13 mole ratio of DMF and water is indicated. The Walden products for all the three salts pass through a maximum while the equivalent conductances show a minimum with increasing DMF content. The maxima in the Walden product are attributed to the dehydration of ions by the cosolvent (DMF).Part I:Indian J. Chem. 14A, 1015 (1976).Deceased.     

Dynamic model for vibronic excitation in low energy atom-molecule collisions

Product state distributions from low energy He⁺N₂ and N⁺₂He collisions are presented. These data, obtained from collision-produced emission spectra, show severe deviations from Franck-Condon behavior which cannot be solely the result of molecular distortion arising from electrodynamic effects. A model based on consideration of the short-range interaction between the collision partners is proposed.     

The magnetic susceptibilities of cobaltocene and chromocene

The magnetic susceptibilities of cobaltocene and chromocene have been measured between 83 and 293 K; for cobaltocene the results suggest an appreciable orthorhombic splitting of the ²∏(σ²πδ⁴ ground state, whilst for chromocene the data provide further support for the ³Δ(σδ³) ground state previously deduced.     

Me2ESiMe3 (E = As,N, P) Compounds—Efficient Reagents for Replacement of the Fluorine Atom by Me2E Group in the Complex [(η6-1-F-3,5-Me2C6H3)(η5-C5EtMe4)Rh](CF3SO3)2 >

Russian Journal of Organic Chemistry -     

Application of infrared spectroscopy to monitoring gas insulated high-voltage equipment: electrode material-dependent SF(6) decomposition

Sulfur hexafluoride is a chemically inert gas which is used in gas insulated substations (GIS) and other high-voltage equipment, leading to a significant enhancement of apparatus lifetime and reductions in installation size and maintenance requirements compared to conventional air insulated substations. However, component failures due to aging of the gas through electrical discharges may occur, and on-site monitoring for risk assessment is needed. Infrared spectroscopy was used for the analysis of gaseous by-products generated from electrical discharges in sulfur hexafluoride gas. An infrared monitoring system was developed using a micro-cell coupled to an FTIR spectrometer by silver halide fibers. Partial least-squares calibration was applied by using a limited number of optimally selected spectral variables. Emphasis was placed on the determination of main decomposition products, such as SOF(2), SOF(4), and SO(2)F(2). Besides the different electrical conditions, the material of the plane counter electrode of the discharge chamber was also varied between silver, aluminum, copper, tungsten, or tungsten/copper alloy. For the spark experiments the point electrode was the same material as chosen for the plane electrode, whereas for partial discharges a stainless steel needle was employed. Complementary investigations on the chemical composition within the solid counter electrode material by secondary neutral mass spectrometry (SNMS) were also carried out. Under sparking conditions, the electrode material plays an important role in the decomposition rates of the gas-phase, but no relevant material dependence could be observed under partial discharge conditions.     

Application of neural network calibrations to an halide ISE array

The Neural Network (NN) technique was applied to the calibration of an ion selective electrode (ISE) array comprising a bromide selective electrode, two chloride ISEs and one thiocyanate ISE. The measured samples were synthetic mixture solutions of chlorides and bromides in concentration ranges such that interference occurs. The NN method allowed to perform the calibration without estimating the coefficients of the Nikolskii-Eisenman theoretical relation. Only the determination of bromide was detailed. The results obtained using this method were better than those obtained using linear multivariate calibration methods.