Dissociative electron capture by 1,3-dithiolanes and 1,3-dioxalanes

A study was carried out on dissociative electron capture by 1,3-dithiolanes and 1,3-dioxalanes. The mechanisms for the fragmentation pathways of the negative ions differ significantly between the oxygen- and sulfur-containing compounds. The (M-H)^– ions are formed with excess internal excitation energy.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 208–210, January, 1990.     

Mass spectra of negative ions of aliphatic ω-oxocarboxylic acid derivatives

Conclusions Fragmentation of the molecules of methyl esters of aliphatic -oxocarboxylic acids upon dissociative capture of electrons includes processes of fragmentation that are characteristic for each functional group individually. It has been established that terminal functional groups separated by a saturated chain of four carbon atoms will interact, thus demonstrating that this molecule can exist in the folded conformation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2238–2246, October, 1984.     

Resonance electron capture mass spectra of some diterpenoid alkaloids

Formation of negative ions from molecules of some diterpenoid alkaloids under conditions of resonance electron capture was studied. Ions formed by capturing low-energy electrons in the lowest unoccupied molecular orbital similar to the *-C=O or *-Ph—CO₂ orbitals contribute predominantly to the mass spectra.     

Oxidation of diazo compounds by triphenyl phosphite ozonide. Quenching of singlet oxygen by diazo compounds

The reaction of triphenyl phosphite ozonide with various types of diazo compounds results in their oxidation, which is accomplished by singlet oxygen (¹O₂) evolved during thermal decomposition of the ozonide. A decrease in the ionization potential of the substrate results in an increase in the overall rate constant of quenching of¹O₂. In the case of 9-diazofluorene, the main channel of¹O₂ quenching is physical quenching.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1567–1571, September, 1994.The work was carried out with the financial support of the Russian Foundation for Basic Research (Project No. 93-03-5231).     

Mass spectra of the negative ions of some dioxanes

It was established by mass spectrometry of negative ions that fragmentation of some 1,3- and 1,4-dioxanes proceeds through intermediate [M-H]⁻ ions. The fragmentation pathway depends on the site of negative charge localization in these ions. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2199–2201, November, 1999.     

Dissociative electron capture by sulfide,sulfoxide, and sulfone molecules

Conclusions The low energy resonance in the negative ion mass spectra of alkyl vinyl, 2,3-epoxypropyl alkyl, and 2, 3-epithiopropyl alkyl sulfies and their sulfoxide and sulfone analogs is related to electron capture in the ^* orbital of the S-C bond. The oxidation state of the sulfur atom has no qualitative effect on the major processes involved in the formation of the negative ions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, 1653–1657, July, 1984.