1977-37-3Relevant articles and documents
EPR study of gamma irradiated DL-methionine sulfone single crystals
Karabulut, Bünyamin,Yildirim, Ilkay
, p. 186 - 189 (2015)
Electron paramagnetic resonance (EPR) study of gamma irradiated dl-2-amino-4-(Methylsulfonyl) butyric acid (dl-methionine sulfone, hereafter dl-ABA) single crystals and powder was performed at room temperature. It has been found that this compound indicates the existence of C.O2- and N.H2 radicals after γ-irradiation. While g and hyperfine splitting values for the N.H2 radical were observed, for the C.O2- radical, only the g factor was measured. The EPR spectra have shown that N.H2 radical has two groups each having two distinct sites and C.O2- radical has one site. The principal g and hyperfine values for all sites were analyzed.
Synthesis and oxidation catalysis of a Ti-substituted phosphotungstate, and identification of the active oxygen species
Takahashi, Eri,Kamata, Keigo,Kikukawa, Yuji,Sato, Sota,Suzuki, Kosuke,Yamaguchi, Kazuya,Mizuno, Noritaka
, p. 4778 - 4789 (2015/10/05)
In this paper, we report the synthesis of a Ti-substituted phosphotungstate, TBA6[(γ-PW10O36)2Ti4(μ-O)2(μ-OH)4] (I, TBA = tetra-n-butylammonium), and its application to H2O2-based oxidation. Firstly, an organic solvent-soluble dilacunary phosphotungstate precursor, TBA3[γ-PW10O34(H2O)2] (PW10), has been synthesized. By the reaction of PW10 and TiO(acac)2 (acac = acetylacetonate) in an organic medium (acetonitrile), I can be obtained. Compound I possesses a tetranuclear Ti core which can effectively activate H2O2 and shows high catalytic performance for several oxidation reactions, such as epoxidation of alkenes, oxygenation of sulfides, oxidative bromination of unsaturated compounds, and hydroxylation of anisole, giving the corresponding oxidation products with high efficiencies and selectivities. The catalytic performance of I is much superior to those of previously reported Ti-substituted polyoxometalates. In addition, I is highly durable during catalysis and can be reused several times while keeping its high catalytic performance. Furthermore, we have successfully isolated the truly catalytically active species for the present I-catalyzed oxidation, TBA6[(γ-PW10O36)2Ti4(μ-η2:η2-O2)4] (II), and its anion structure has been determined by X-ray crystallographic analysis. All of the four Ti2-μ-η2:η2-peroxo species in II are active for stoichiometric oxidation (without H2O2), and II is included in the catalytic cycle for I-catalyzed oxidation.
Niobium peroxo complexes with organic ligands as catalysts of organic sulfide oxidation in two-phase systems
Siukaeva,Fedorova,Aslanov,Tarakanova,Anisimov
, p. 289 - 291 (2007/10/03)
New niobium peroxo complexes with various ligands were prepared, and their activity as catalysts for the selective oxidation of organic sulfides with hydrogen peroxide was evaluated. Copyright
