Svistunova I.V.,Far Eastern Federal University |
Shapkin N.P.,Far Eastern Federal University |
Nikolaeva O.V.,Pacific State University of Economics |
Apanasenko O.A.,Far Eastern State Technical University
Russian Journal of General Chemistry | Year: 2011
Factors determining the reaction of metal β-diketonates with hydrazine, in particular the nature of central metal ion and structure of β-diketonate ligand, are discussed. The possibility for the preparation of other heterocyclic compounds via reaction of metal acetylacetonates with phenylhydrazine, o-phenylenediamine, urea, and thiourea was studied. © 2011 Pleiades Publishing, Ltd.
Li X.,Changchun University |
Li D.,Changchun University |
Shmidt I.,Pacific State University of Economics |
Grishchenko V.V.,Pacific State University of Economics |
Kalenik T.K.,Pacific State University of Economics
Journal of Medicinal Plants Research | Year: 2011
Rutin and its hydrolyzing enzymes naturally occur in tartary buckwheat grains. However, it is not known whether these enzymes affect the preparations of tartary buckwheat flavonoids. In this study, water followed by ethanol (3:7), or premixed 70% ethanol, was used to extract flavonoids from flours or hulls of tartary buckwheat grains. The flavonoid compositions of hydrated ethanol extracts were analyzed by HPLC, and their antioxidative capacities were evaluated by free radical scavenging test and reducing power assay. The premixed 70% ethanol inhibited the activity of rutin hydrolyzing enzymes to produce the extract of high rutin content, while the addition of water followed by ethanol led to the degradation of rutin to produce the extract of high quercetin content. The antioxidative activities of high quercetin extracts were more than those of high rutin extracts. ©2011 Academic Journals.
Lukyanova O.N.,Pacific Research Fisheries Center |
Ireykina S.A.,Pacific Research Fisheries Center |
Chernyaev A.P.,Pacific Research Fisheries Center |
Vazhova A.S.,Pacific Research Fisheries Center |
Boyarova M.D.,Pacific State University of Economics
Russian Journal of Marine Biology | Year: 2010
A complex ecotoxicological assessment of several estuarine zones of the Razdol'naya, Barabashevka, Ryazanovka, and Gladkaya rivers in Amur Bay, and the Artyomovka and Sukhodol rivers in Ussyry Bay was carried out in 2007 and 2008. Bottom sediments in the estuary of the Kievka river were collected in 2009. The content of petroleum hydrocarbons was determined in the water and bottom sediments of riverine and marine sectors of estuaries and the total toxicity of bottom sediments was tested with the use of mysids. Bottom sediments from a small river on Reineke Island, in which the concentrations of primary pollutants corresponded to the background values for the entire Peter the Great Bay, were used as a control. The content of organochlorine pesticides in the muscles and liver of the Redeye Eastern Redfin (Tribolodon brandtii) was determined and molecular biomarkers of oxidative stress in organs of the Redlip Mullet (Liza haematocheila) analyzed. The amount of wastewater and pollutants flowing into Amur Bay and Ussyry Bay with some of the rivers was estimated. The correlation coefficient between the toxicity of bottom sediments and the petroleum hydrocarbons content in them was found. The higher sediment toxicity in the riverine zone, as compared to the marine zone, proves the concept of the "river-sea" biogeochemical barrier. © 2010 Pleiades Publishing, Ltd.
Ustynyuk Yu.A.,Moscow State University |
Babin Y.V.,Pacific State University of Economics |
Savchenko V.G.,Pacific State University of Economics |
Myshakin E.M.,Pacific State University of Economics |
Gavrikov A.V.,Moscow State University
Russian Chemical Bulletin | Year: 2010
The mechanism of ethylene hydroformylation on model organoplatinum hydrides [(R2PO)2H]Pt(PR3)(H)] (R = H, Me, CF 3) was studied within the framework of the density functional theory with the PBE gradient-corrected functional and the TZ2p basis set. The presence of a free coordination site in these square-planar 16-electron platinum complexes provides the possibility of alkene coordination in the first step without energetically unfavorable dissociation of one of the metal-ligand bonds. High strength of the -PR2O-H....O-R2 hydrogen bond results in the formation of a bidentate ligand in the coordination sphere of the metal atom. This ligand makes the geometry of the catalytic center rigid, thus enhancing the regioselectivity of the process. The proton can reversibly migrate with ease within the -PR2O-H... O-R2 hydrogen bond, thus providing fine adjustment of the electron density in the catalytic center in each reaction step and acting as a molecular switch. The rate-limiting step in the hydroformylation is the CO insertion into the Pt-Et σ-bond. Electron-donating Me groups at the phosphorous atoms hamper, while electron-withdrawing CF3 groups facilitate, the process. © 2010 Springer Science+Business Media, Inc.