Spinor Field in Bianchi type-I Universe: regular solutions

Self-consistent solutions to the nonlinear spinor field equations in General Relativity has been studied for the case of Bianchi type-I (B-I) space-time. It has been shown that, for some special type of nonliearity the model provides regular solution, but this singularity-free solutions are attained at the cost of broken dominant energy condition in Hawking-Penrose theorem. It has also been shown that the introduction of $\Lambda$-term in the Lagrangian generates oscillations of the B-I model, which is not the case in absence of $\Lambda$ term. Moreover, for the linear spinor field, the $\Lambda$ term provides oscillatory solutions, those are regular everywhere, without violating dominant energy condition. Key words: Nonlinear spinor field (NLSF), Bianch type -I model (B-I), $\Lambda$ term PACS 98.80.C CosmologyComment: RevTex, 21 page

Reactions of 5-indolizyl lithium compounds with some bielectrophiles

Indolizyl-5-lithium anions react with succinic and phtalic anhidrides giving 1,4-keto acids, with oxallyl chloride giving 1,2-diketone, and with ethyl pyruvate giving 1,2-hydroxyacid. However, with α-halocarbonyl compounds, they react in different ways, forming the products of selective bromination at C-5 (with α-bromo ketones and esters of α-bromo acids) and 5-chloroacetyl indolizines. © 2017 by the Authors

Crystal structure and properties of [OsO2(NH3) 4]SO4 • H2O

The structure of a single crystal of tetraammindioxoosmium(VI) sulfate [OsO2(NH3)4]SO4 • H 2O, which is synthesized by the reaction of K2[OsO 2(OH)4] with (NH4)2SO4 in an aqueous solution, is investigated using X-ray diffraction analysis. The compound crystallizes in the monoclinic crystal system, space group P2 1/c, a = 13.102(2) Å, b = 6.158(3) Å, c = 11.866(2) Å, β = 98.13(2)°, and Z = 4. The [OsO2(NH 3)4]SO4 • H2O compound has an island structure. Two crystallographically independent osmium atoms are situated at the centers of symmetry, and their octahedral coordination includes two oxygen atoms and four nitrogen atoms of the ammonia molecules. In both octahedra, the osmyl group is linear. The Os-O distances in the octahedra are identical within the standard deviations [Os(1)-O, 1.762(2) Å; Os(2)-O, 1.769(2) Å]. The Os-N bond lengths vary from 2.082(3) to 2.101(3) Å. The cationic complexes, SO4 groups, and water molecules are linked via the system of hydrogen bonds. The assignment of the absorption bands in the IR spectrum of the compound synthesized is performed, and its thermal behavior in air is studied. © Nauka/Interperiodica 2007

Crystal structure and properties of K2[OsO2(C 2O4)2] • 2H2O

The synthesis and X-ray diffraction study of the compound K 2[OsO2(C2O4)2] • 2H2O are performed. The compound crystallizes in the triclinic crystal system, space group P 1̄, a = 6.545(1) Å, b = 6.835(2) Å, c = 7.595(2) Å, α = 85.76(2)°, β = 65.33(2)°, γ = 71.14(2)°, and Z = 1. The osmium atom is located at the center of symmetry and has a distorted octahedral coordination formed by oxygen atoms: two oxygen atoms of the osmyl group occupy the apical positions [Os-O, 1.730(2) Å], and four oxygen atoms of the oxalate ions lie in the equatorial plane. The K+ cation is surrounded by ten oxygen atoms located at different K-O distances in the range from 2.787(2) to 3.158(2) Å. The assignment of the absorption bands in the IR spectrum of K2[OsO2(C 2O4)2] • 2H2O is performed. The electronic absorption spectra of the compound are recorded in different solvents, and the thermal behavior in air is studied. © 2007 Pleiades Publishing, Inc

Reactions of 5-indolizyl lithium compounds with some bielectrophiles

Indolizyl-5-lithium anions react with succinic and phtalic anhidrides giving 1,4-keto acids, with oxallyl chloride giving 1,2-diketone, and with ethyl pyruvate giving 1,2-hydroxyacid. However, with α-halocarbonyl compounds, they react in different ways, forming the products of selective bromination at C-5 (with α-bromo ketones and esters of α-bromo acids) and 5-chloroacetyl indolizines. © 2017 by the Authors

Crystal structure and properties of K2[OsO2(C 2O4)2] • 2H2O

The synthesis and X-ray diffraction study of the compound K 2[OsO2(C2O4)2] • 2H2O are performed. The compound crystallizes in the triclinic crystal system, space group P 1̄, a = 6.545(1) Å, b = 6.835(2) Å, c = 7.595(2) Å, α = 85.76(2)°, β = 65.33(2)°, γ = 71.14(2)°, and Z = 1. The osmium atom is located at the center of symmetry and has a distorted octahedral coordination formed by oxygen atoms: two oxygen atoms of the osmyl group occupy the apical positions [Os-O, 1.730(2) Å], and four oxygen atoms of the oxalate ions lie in the equatorial plane. The K+ cation is surrounded by ten oxygen atoms located at different K-O distances in the range from 2.787(2) to 3.158(2) Å. The assignment of the absorption bands in the IR spectrum of K2[OsO2(C 2O4)2] • 2H2O is performed. The electronic absorption spectra of the compound are recorded in different solvents, and the thermal behavior in air is studied. © 2007 Pleiades Publishing, Inc

Crystal structure and properties of [OsO2(NH3) 4]SO4 • H2O

The structure of a single crystal of tetraammindioxoosmium(VI) sulfate [OsO2(NH3)4]SO4 • H 2O, which is synthesized by the reaction of K2[OsO 2(OH)4] with (NH4)2SO4 in an aqueous solution, is investigated using X-ray diffraction analysis. The compound crystallizes in the monoclinic crystal system, space group P2 1/c, a = 13.102(2) Å, b = 6.158(3) Å, c = 11.866(2) Å, β = 98.13(2)°, and Z = 4. The [OsO2(NH 3)4]SO4 • H2O compound has an island structure. Two crystallographically independent osmium atoms are situated at the centers of symmetry, and their octahedral coordination includes two oxygen atoms and four nitrogen atoms of the ammonia molecules. In both octahedra, the osmyl group is linear. The Os-O distances in the octahedra are identical within the standard deviations [Os(1)-O, 1.762(2) Å; Os(2)-O, 1.769(2) Å]. The Os-N bond lengths vary from 2.082(3) to 2.101(3) Å. The cationic complexes, SO4 groups, and water molecules are linked via the system of hydrogen bonds. The assignment of the absorption bands in the IR spectrum of the compound synthesized is performed, and its thermal behavior in air is studied. © Nauka/Interperiodica 2007

Three-component reactions of 3-arylidene-3h-indolium salts, isocyanides and amines

A multicomponent reaction of isocyanides with aryl(indol-3-yl)methylium salts and amines has been found. A series of aryl(indol-3-yl)acetimidamides was obtained in up to 96% yields. In the case of ethyl isocyanoacetate, the reaction is followed by cyclization to form 3,5-dihydro-4H-imidazol-4-one derivatives. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Donor-Acceptor Cyclopropane Ring Opening with 6-Amino-1,3-dimethyluracil and Its Use in Pyrimido[4,5- b]azepines Synthesis

A scandium trifluoromethanesulfonate-catalyzed reaction of donor-acceptor cyclopropanes with 6-amino-1,3-dimethyluracil was found to proceed as three-membered ring opening via nucleophilic attack of the C(5) atom of an ambident nucleophile serving as an enamine equivalent. It was shown that, under basic conditions, the obtained products underwent cyclization to 6,7-dihydro-1H-pyrimido[4,5-b]azepine-2,4,8-triones, an interesting subclass of nucleobase analogues. © 2021 American Chemical Society