Ruthenium tetroxide oxidation of N-methyl-isoxazolidine: Computational mechanistic study

In this paper, we report a mechanistic study of RuO₄-catalyzed oxidation on the 2-methylisoxazolidine through computational methods. The investigation was performed taken into consideration that the oxidation could take place on different sites of the substrate. This reaction occurs in two steps, involving a double H-transfer. In particular, the rate-determining one implies a [3 + 2] one-step, but asynchronous mechanism. In the first step, when methyl propanoate is used as solvent, the formation of an ion pair, which affords to the product, is involved. Furthermore, the study highlights that all carbon atoms of the isoxazolidine system, near to the heteroatoms, can undergo the oxidation process. The detected selectivity is correlated to the stability of the corresponding carbocations, leading to the N-methylisoxazolidin-3-one as preferred product.     

EPR study of the dinitrogen tetroxide dissociation in organic solvents

The dinitrogen tetroxide homolytical dissociation constants K _DIS are determined in organic solvents. The values are the highest in non-donor and the lowest in n-donor solvents. The variations of K _DIS with solvent are interpreted in terms of electron donor-acceptor interactions between dinitrogen tetroxide and electron donor molecules.     

Spectroscopic study of Mentha oils

The visible fluorescence and excitation spectra of Mentha oils (Japanese mint oil, peppermint oil and spearmint oil) have been recorded. Different physical constants which are characteristic of the fluorescent molecules have been calculated for all three oils. Results reveal that the same group of organic compounds dominate in the oils of peppermint and spearmint, whereas some different compound is present in Japanese mint oil. It is also found that the fluorescence intensity of these oils is comparable to that of Rhodamine 6G dye in methanol solution. Our studies suggest that Mentha oils may be a useful lasing material in the 450–600 nm wavelength range.     

Spectroscopic study of germanium-containing compounds

Conclusions The values of C=0 in the IR spectra and the position of the band from the n ^* electronic transition in the UV spectra of the amides R¹CONR²R³ vary linearly with the inductive effect of the R¹ substituent (for R²=R³=H, Alk). This may indicate the absence of the intramolecular coordination Ge 0, where or. The substituent R¹=Ge(C₂H₅)₂ exhibits electron-acceptor properties besides a +I-effect.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 349–352, February, 1984.     

An MS Xα study of the electronic structure of osmium tetroxide

Multiple scattering Xα calculations of the electronic structure of OsO₄ are performed using various sets of atomic spheres radii. It is shown that the use of overlapping atomic spheres leads to a good agreement with photoelectron and electronic absorption spectra.     

Spectroscopic study of calcium sulfite thermolysis

The thermal conversion of calcium sulfite into calcium sulfate in air was studied by thermogravimetric analysis and ESR and IR spectroscopy. The water of crystallization of CaSO₃ · 0.5H₂O was found to be involved in the formation of the heat-generated radical ion SO ₂ ^? . A thermolysis mechanism is suggested.     

Spectroscopic study of bituminous oxidative stress

Bitumen, as each organic substance, is a product which alters over time. Indeed, roads deteriorate under the effect of several phenomena. A number of studies have been undertaken to increase the quality of road's coating, mostly by adding polymer to bitumen. This work was based on the study, by electron paramagnetic resonance (EPR), FTIR and Synchronous UV fluorescence, of different base and modified bitumens after different treatments used to simulate the ageing (gamma irradiation, thermal treatment). Our purpose was to compare and correlate the results obtained by different techniques to improve the knowledge of bitumen's reactivity and evolution submitted to ageing phenomena.     

A Spectroscopic study of phenylboron halides

Phenylfluoroboranes have been prepared by the fluorination ofthe corresponding bromides with titanium tetrafluoride. The infrared spectra of the phenylhaloboranes, R_3−nBXn (RC₆H₅, XF, Cl, Br, I), have been recorded in the 4000–4250 cm⁻¹ region; an assignment of the fundamentals is suggested and characteristic frequency trends are discussed. An evaluation of the spectral data suggests that the structure of phenylfluoroboranes is distinctly different from that of the other halides in the series.     

An XPS study of the valence levels of alpha plutonium

The X-ray photoelectron spectum of the valence levels (0–25eV binding energy) of α-Pu has been obtained. The 5f bandwidth (1.8eV) results from significant 5f-5f overlap in the monoclinic phase.     

Alkane oxidation by osmium tetroxide

Aqueous alkaline OsO4 at 85 degrees C oxidizes saturated alkanes, including primary, secondary, and tertiary C-H bonds. Isobutane affords tert-butanol in quantitative yield based on consumed OsO4. Cyclohexane is oxidized to a mixture of adipate and succinate. Ethane and propane are oxidized to acetate, which itself is further oxidized under the reaction conditions. A few turnovers of isobutane oxidation have been accomplished using NaIO4 as the terminal oxidant. The alkane oxidation is an example of ligand accelerated catalysis, as hydroxide binding to OsO4 is required for reaction. A concerted mechanism involving [3+2] addition of a C-H bond to two oxo groups of OsO4(OH)- is suggested, analogous to the pathways for dihydroxylation of alkenes by OsO4(L) and for addition of H2 to OsO4(L).     

Spectroscopic study of organosilicon derivatives of thiophene

Substituents in disubstituted thiophenes have an additive effect on the chemical shifts of the ring hydrogen atoms. The electronic effects of organosilicon substituents are transmitted via inductive and conjugation (d-p interaction) mechanisms. The effect of d-p interaction in the Si-ring bond is absent for Si(OC₂H₅) and SiF₃ substituents.See [1] for communication III.Translated from Khimiya Geterotsiklicheskikh Soedinenli, No. 11, pp. 1483–1488, November, 1972.     

Spectroscopic study of organosilicon derivatives of thiophene

The IR spectra of organosilicon derivatives of thiophene were investigated. A comparison of the results with the literature data made it possible to isolate the characteristic absorption bands of the substituted thiophene ring and to reveal some regularities in the IR spectra of thienylsilanes. The inductive constants of substituted thienyl groups were calculated from the experimental(Si-Cl) values. An analysis of the values shows that electron-donor substituents X lower the acceptor capacity of the thienyl substituent as a whole, while electron-acceptor substituents increase it.See [1] for communication IV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 477–481, April, 1974.     

Spectroscopic study of organosilicon derivatives of thiophene

It is shown that the chemical shifts of hydrogen atoms in the 3 position of the thiophene ring in the PMR spectra of 2-substituted thiophenes are linearly associated with the Hammett _n substituent constants. On the basis of this, it was concluded that silyl substituents in 2-silylthiophenes have electron-acceptor character. It was established that the degree of d–p conjugation between the d orbitals of the silicon atom and the p electrons of the thiophene ring depends on the nature of the other three substituents attached to the silicon atom. The data from the IR spectra of organosilylthiophenes that contain a Si-H bond also attest to the presence of d–p conjugation in these compounds.See [1] for communication I.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 911–915, July, 1972.     

Reaction of thebaine with dinitrogen tetroxide

Treatment of thebaine with dinitrogen tetroxide gave a mixture of 14β-nitrocodeinone (23%) and 8-nitrothebaine (7%).     

Microencapsulation of osmium tetroxide in polyurea

[reaction: see text] Osmium tetroxide has been microencapsulated in a polyurea matrix using an in situ interfacial polymerization approach. These microcapsules have been effectively used as recoverable and reusable catalysts in the dihydroxylation of olefins     

Spectroscopic study of mixed metal halide-acetonitrile complexes

Mixed metal halide-acetonitrile complexes of nickel(II) and cobalt(II) with zinc(II) in which the nickel:zinc ratio is 1 : 1 and the cobalt:zinc ratio is either 1 : 1 or 1 : 2 have been studied. The structural components of these solid complexes are inspected on the basis of their electronic absorption and far i.r. spectra.