Effect of aryl substituents on the rate of dark decolorization of photochromic spirochromenes of the indoline series

The introduction of aryl substituents in the 3 and 7 positions of the indoline spirochromene molecule gives rise to a certain amount of slowing down of dark decolorization in toluene and dioxane; similar changes in the 5, 6, and 8 positions do not change the rate appreciably.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 79–81, January, 1977.     

Electron spin echo of CH2OH radicals adsorbed in A-type zeolites

Data on the trapping site of radicals in zeolite α-cages have been obtained by the analysis of modulation effects in the electron spin echo of CH₂OH radicals produced by irradiation in A-type zeolite with adsorbed methyl alcohol.     

Electronic absorption spectra of merocyanine forms of spiropyrans

A simple method is proposed for the measurement of the absorption spectra in the visible and UV regions of photocolored solutions of spiropyrans, formed by the action of constant lowintensity UV irradiation, and for the construction, on the basis of these data, of the absorption spectra of the merocyanine forms of spiropyrans. The absorption spectra of the merocyanine forms of two spiropyrans in various solvents are examined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1534–1538, November, 1972.     

Three-membered rings communication 8. perfluorocyclobutenylethylenimides

Conclusions Perfluorocyclobutene, in contrast to perfluoroisobutylene, forms products of the replacement of the vinyl fluorine atom in the reaction with ethylenimines and ethyleniminomethylamines, similar to the case of the reaction with the usual secondary amines.The article is published on the basis of a resolution of the Conference of Editors-in-Chief of the Journals of the Academy of Sciences of the USSR from July 12, 1962, as the dissertation work of Z. E. Samoilova.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1030–1035, May, 1970.     

Orientation-selected 15N-HYSCORE detection of weakly coupled nitrogens around the archaeal rieske [2Fe-2S] center

The weakly coupled 15N atoms around a reduced Rieske [2Fe-2S] cluster of the uniformly 15N-labeled, hyperthermostable archaeal Rieske protein appear to produce readily observable cross-peaks in the HYSCORE spectra, with the well-resolved couplings of 0.3-0.4 MHz for the Nepsilon and 1.1 MHz for the peptide backbone nitrogens, in addition to the contributions from the coordinated Ndelta atoms. These features can be used for structure-mechanism studies of the biological redox protein system involving the weakly coupled nitrogens in coupled electron-proton transfer reactions.     

Chitin-based magnetic composite for the removal of contaminating substances from aqueous media

A method of obtaining multipurpose magnetic chitin, which combines the magnetic properties of magnetite and the adsorption properties of polysaccharide, was proposed. The possibility of using chitin-(CT) and chitosan (CS)-containing magnetic composites for the adsorption of inorganic ions Co^II and Cr^VI and organic substances (2- and 4-nitrophenols) from aqueous media was analyzed. It was shown that the adsorption capacity of magnetic chitin with respect to Co^II and Cr^VI ions reached 41 mg g^?1 and 15 mg g^?1, respectively. The maximum adsorption capacity for 4-nitrophenol (19 mg g^?1 per CT-containing magnetic composite or 56 mg g^?1 per chitin component) was about three times higher than for 2-nitrophenol. The obtained adsorbent Fe₃O₄/CT is environmentally friendly and reusable.

     

1-octadecyl- and 3,3-diphenyl-substituted photochromic indolinospirochromenes

A number of photochromic indolinospirochromenes that contain an octadecyl substituent in the 1 position were synthesized. The introduction of an octadecyl group in place of a methyl group increases the stability of the merocyanine form in solution but does not change its spectral characteristics. On the other hand, the introduction of phenyl groups in place of methyl groups in the 3 position does not change the stability of the merocyanine but gives rise to a bathochromic shift of the long-wave absorption band.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 51–54, January, 1980.