ELECTRONIC STRUCTURE AND CHEMICAL BOND IN 9,9,10,10-TETRAETHYNYL-9,10- DIHYDRODISILAANTHRACENE

Journal of Structural Chemistry - Atomic and electronic structures of cyclic organosilicon compound 9,9,10,10-tetraethynyl-9,10-dihydrodisilaanthracene are studied by the density functional theory....     

Cobalt(II) and nickel(II) complexes with 1-amino-8-hydroxynaphthalene-2,4-disulfonic acid in condensation reactions with aromatic carbonyl derivatives

The condensation reaction of cobalt(II) and nickel(II) complexes with 1-amino-8-hydroxynaphthalene-2,4-disulfonic acid and aromatic carbonyl compounds (benzoin and 2-hydroxy-1-naphthaldehyde) was carried out. Four new complexes (I–IV) were synthesized. The compounds were identified by elemental analysis, powder X-ray diffraction, thermogravimetry, magnetic susceptibility, IR and diffuse reflection spectroscopy, and EXAFS. The spatial arrangement of the donor centers of the ligands in the coordination units (tetrahedral for I, octahedral for II and III, and square planar for IV) was determined.     

Copper(II) and nickel(II) complexes with bis(azomethine)—a condensation product of 1-phenyl-3-methyl-4-formyl-5-mercaptopyrazole with 1,3-diaminopropan-2-ol

The copper(II) and nickel(II) complexes based on bis(azomethine), which is the condensation product of 1-phenyl-3-methyl-4-formyl-5-mercaptopyrazole with 1,3-diaminopropan-2-ol, are synthesized. Bis-azomethines can form both binuclear and mononuclear complexes in which the hydroxy group is not involved in coordination. The binuclear copper(II) complexes with the acetate and pyrazolate bridges exhibit an antiferromagnetic exchange, which strength is determined by the nature of the bridge (2J = ?154 and ?424 cm^?1, respectively). The structure parameters of the coordination spheres of the complexes are determined by X-ray absorption spectroscopy. The structure of the CHCl₃ solvate of the binuclear copper(II) complex with the pyrazolate bridge is solved by X-ray diffraction analysis (CIF file CCDC 964655).     

Reactions of nitrogen oxides (NO,N2O) with the surface of a copper-chromium oxide catalyst

Weight-space and IR spectroscopic methods have been used to investigate the reaction of NO and N₂O with the surface of a copper-chromium oxide catalyst in the form of copper chromite with a 20% excess of Cr₂O₃. Comparisons have been made between the relative reactivities of the different oxides (NO, N₂O, O₂) in oxidation of the Cu⁺ and Cu^o surface centers. The role of these centers in oxidation of CO by oxygen and by nitrogen oxides is discussed.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 21, No. 3, pp. 338–343, May–June, 1985.     

Intramolecular thermal transformations of N-phthalimidoaziridines: 1,3-dipolar cyclo-addition and rearrangements*

The intramolecular thermal cycloaddition of N-phthalimidoaziridines at multiple bonds of substituents with the intermediate formation of azomethine ylides leads to condensed pyrrole derivatives, in which the five-membered ring is adjacent to a five-, six-, or seven-membered ring. Rearrangements, which sometimes become the predominant reactions, compete with cycloaddition. Thus, aziridines with aryl substituents readily isomerize to give imines with a 1,2-shift of the phthalimide group to one of the carbon atoms. Aziridines with one electron-withdrawing substituent probably do not open to give 1,3-dipoles but rather undergo a Cope-type rearrangement involving the three-membered ring and C = O bond of the second substituent. Even in intramolecular reactions, very low activity is found for the cyano group triple bond and aromatic ring bonds as dipolarophiles.     

Chemical and Electrochemical Synthesis,Structure, and Properties of Metal Chelates of Tridentate N,S-Containing Azomethinazo Ligands

Novel Cu(II), Co(II), Ni(II), and Zn(II) complexes of 5-methyl-2-phenyl-4-[(4-phenylazo)anilinemethylylidene]- 2,4-dihydro-3H-pyrazole-3-thione and 5-methyl-4-[4-methyl-2-(4-methylphenylazo)anilinemethylylidene]- 2-phenyl-2,4-dihydro-3H-pyrazole-3-thione, i.e. ligands containing the phenylazo group in the ortho and para positions of the aniline fragment, were synthesized by the chemical and electrochemical methods. The complexes and ligands were characterized by IR, ¹H NMR, X-ray absorption spectroscopy and magnetochemistry. The azo group of the ligands is not involved in coordination to the metal.     

Local atomic environments and magnetic properties of copper binuclear azomethine complexes

Local atom environment in binuclear chelate Cu(II) complexes on the basis of azomethine ligands was investigated by extended X-ray absorption fine structure spectroscopy. The temperature magnetic measurements indicated ferro- or antiferromagnetic exchange in these complexes. A direct correlation between the character of the exchange magnetic interaction and the type of the ligand coordination in these complexes was established.     

Action of the transferase activity of phospholipase D on rat liver mitochondria

The action of phospholipase D on rat liver mitochondria in the presence of methanol, glycerol, and ethanolamine has been studied. The phospholipid compositions of the modified and native mitochondria have been determined. Incubation of the mitochondria with phospholipase D led to a considerable decrease in the activities of cytochrome c oxidase and NADH-cytochrome reductase.Institute of Marine Biology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Far Eastern State University, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 364–369, May–June, 1982.     

The electronic structure of iron carbonyl complexes as probed by X-ray emission spectroscopy and quantum-chemical calculations

The electronic structure of the polynuclear iron carbonyl complexes [Et₂N][Fe₄N(CO)₁₂], [Et₄N]₂[Fe₅C(CO)₁₄], and [Et₄N]₂[Fe₆C(CO)₁₆] has been studied by X-ray emission spectroscopy and quantum-chemical calculations. The fine structure of the FeKβ₅ X-ray emission spectra characterizes the distribution of iron valence p electrons over the molecular orbitals of the compounds. Comparison of the fine structure of the FeKβ₅ X-ray emission spectra with the densities of states of all atoms in the molecules has made it possible to determine in detail the character and specific features of chemical bonding in the complexes.