Reaction of SeOCF3 and SeO2CF3 groups with π-electron systems in ground and excited states

The dipole moments and ultraviolet spectra were measured for selenium compounds containing SeOCF₃ and SeO₂CF₃ groups. It is shown that in the ground state the SeO₂CF₃ group has a greater tendency toward conjugation with the -electron system of the benzene ring thandoes the SeOCF₃ group. In the ground state, selenium compounds containing SeOCF₃ and SeO₂CF₃ groups have a smaller conjugation effect than corresponding sulfur compounds. Oxidation of SeCF₃ to SeOCF₃ decreases the degree to which the uncollectivized electrons of selenium take part in conjugation with electron-accepting groups. In the unexcited state the free electrons of selenium in SeCH₃ and SeCF₃ groups are more mobile than those of sulfur in SCH₃ and SCF₃ groups, and the * level of the Se=O groups is lower than that of the S=O group.     

Structural Properties and State of a Zirconium Dioxide Surface Layer Modified with Mе3+ Cations

Russian Journal of Physical Chemistry A - The effect Ме3+ (Al, Y, Sc, Fe, and Mn) cations on the structural properties and state of a zirconium dioxide surface layer is investigated....     

Solvatofluorochromic properties of sulfonyl fluoride derivatives of 5-aryl(heteroaryl)-2-phenyl-1,3,4-oxadiazole, promising fluorescent probes

The spectral characteristics of seven 5-aryl(heteroaryl)-2-phenyl-1,3,4-oxadiazole derivatives, containing an expressed electron-accepting grouping such as sulfonyl fluoride or sulfonyldifluoromethane in the para position of the phenyl substituent, have been investigated in solvents of various polarity. The insignificant effect of the n^* levels of the SO₂X grouping on the fluorescence properties of the compounds studied was established, as a result of which they are highly effective organic luminophors in the near ultraviolet and violet spectral ranges. The presence was shown of a significant solvatochromic effect exerted particularly clearly in derivatives with electron-donating groups in the 5-aryl substituent. As a result of this, the compounds indicated may be recommended for use as fluorescent probes in medicine and biology. Adiabatic flattening in the excited state of the sterically hindered methoxy derivative and the formation of a TICT state are considered, leading to quenching of the fluorescence of dimethylamino derivatives in media of high polarity.Kharkov State University, Kharkov 310077. Institute of Monocrystals, Academy of Sciences of the Ukraine, Kharkov 310001. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 988–994, July, 1997.     

Synthesis and chemical characteristics of 2-substituted thiazoline-4,5-diones. (Review)

Methods for the production of 2-substituted thiazoline-4,5-diones and their thermolysis in the presence of nucleophiles and dienophiles are examined. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1283–1301, September, 2006.     

Effect of substituents in the cumulene and aryl fragments of aroylketenes on the stereoselectivity of diels-alder heteroreaction with mono-, Bi-, and polycyclic terpenoids containing a carbonyl group

Stereoisomeric adducts, substituted (R)-, (S)-spiro[6-aryldioxin-4-ones] have been obtained by thermolysis of 5-arylfuran-2,3-diones in the presence of menthone and allobetulone.     

Chemistry of the intekaction of a peroxy radical with manganese stearate

Conclusions A ketone and a basic salt of trivalent manganese have been identified as the final products of the reaction between a peroxy radical and bivalent manganese. During the reaction the change in the valence of the manganese is accompanied by the conversion of the peroxy radical into an anion.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 1217–1218, December, 1966.     

Heterostructures based on gapless graphene with different Fermi velocities

The properties of a single heterojunction between gapless graphenes with identical work functions but different Fermi velocities have been investigated. Reflection and transmission coefficients are obtained for charge carriers passing through this junction. It is shown that total internal reflection (with a critical angle the same as for light incident at an interface between two media) may occur in it.