3185-99-7Relevant academic research and scientific papers
Hydrolytic stability and hydrogen peroxide activation of zirconium-based oxoclusters
Faccioli, Francesco,Bauer, Matthias,Pedron, Danilo,Sorarù, Antonio,Carraro, Mauro,Gross, Silvia
, p. 210 - 225 (2015)
The hydrolytic stability of [Zr6(OH)4O4{O(O)CC(CH3)=CH2}12] (Zr6), and [Zr6O4(OH)4{O(O)CCH2CH=CH2}12]2·6[CH2=CHCH2C(O)OH] (Zr12) oxoclusters in different environments was thoroughly investigated by FTIR, Raman, and X-ray photoelectron spectroscopy (XPS). Specific information about the local structures around the Zr centers during the stability tests was achieved by in situ extended X-ray absorption fine structure (EXAFS) measurements, and the exact compositions were determined by inductively coupled plasma MS (ICP-MS) and elemental analysis. By this multidimensional spectroscopic approach, an overview on the structures formed after different treatments could be gained. The stability of the oxoclusters was then investigated in the presence of hydrogen peroxide, and the formation of peroxo-metal complexes was detected. Thus, a kinetic study was performed in acetonitrile to evaluate the performances of the oxoclusters as oxygen transfer catalysts. The oxidation of methyl p-tolyl sulfide to the corresponding sulfoxide and sulfone was chosen as a model reaction; in some cases, an interesting selectivity towards the formation of the sulfone was found over more than 4700 catalytic cycles.
Efficient oxidation of sulfides catalyzed by a temperature-responsive phase transfer catalyst [(C18H37)2(CH 3)2N]7 PW11O39 with hydrogen peroxide
Xue, Xiaoling,Zhao, Wei,Ma, Baochun,Ding, Yong
, p. 73 - 76 (2012)
A temperature-responsive phase transfer catalyst [(C18H 37)2(CH3)2N]7PW 11O39, could act as an efficient catalyst for selective oxidation of sulfides with 30% aqueous H2O2. Various kinds of sulfides were successfully oxidized to their corresponding sulfones with over 96% yields in a relatively short time and mild conditions. During reaction at 333 K, the catalyst dissolved completely and the oxidation was conducted homogeneously. Before and after reaction, the catalyst was insoluble with cooling, so it is easily recovered and reused. The catalyst was characterized by elemental analysis, FT-IR and 31P NMR.
Evidence for cyclodextrin dioxiranes
Deary, Michael E.,Davies, D. Martin
, p. 17 - 29 (1998)
α-Cyclodextrin, β-cyclodextrin, 2,6-di-O-methyl-β-cyclodextrin, methyl-β-cyclodextrin and sucrose have been oxidised by aqueous bromine solution at neutral pH. Both ketone and carboxylic acid containing materials are among the products of the oxidations. For α-cyclodextrin there is clear 13C NMR evidence for the presence of a ketone group and its hydrate form. This together with the continued ability of the product to complex p-nitrophenol indicates that the ketone is present at the secondary rim of an intact cyclodextrin ring. A pH dependence for the reaction of bromine with cyclodextrin shows that the maximum rate of bromine loss roughly coincides with the maximum concentration of hypobromous acid, HOBr, indicating that this is the reactive species in these oxidations. The results are consistent with a mechanism involving attack by one of the secondary hydroxyls of cyclodextrin on HOBr, with Br- leaving to yield an intermediate dehydroxy hydroperoxy cyclodextrin that subsequently decomposes to a keto-cyclodextrin via a Kornblum-De La Mare-type reaction. An alternative pathway prevails when the reaction is carried out under alkaline conditions, where carboxylic acids are the principle products. The keto derivatives produced by bromine oxidation at neutral pH are capable of catalysing the oxidation of p-nitrophenol and aryl-alkyl sulfoxides by peroxomono-sulfate in an analogous way to cyclohexanone, which is known to form a dioxirane upon reaction with peroxomonosulfate. It is likely that dioxirane formation is responsible for the observed catalysis in the present case also.
Visible light generation of chromium(V)-oxo salen complexes and mechanistic insights into catalytic sulfide oxidation
Dames, Angeline,Fung Lee, Ngo,Klaine, Seth,Zhang, Rui
, (2020)
Visible light irradiation of the photo-labile salen-chromium(III) chlorate or bromate precursors produced salen-chromium(V)-oxo complexes that were spectroscopically and kinetically indistinguishable from those formed by chemical oxidation of chromium(III) salens with PhI(OAc)2. The photochemistry observed in this work is ascribed to the heterolytic cleavage of the O-X bond in the apical counterion that results in a two-electron oxidation of the metal to form the chromium(V)-oxo species. Second-order rate constants for oxidation reactions of 3 with organic substrates were determined under pseudo-first order condition, and particularly low level of reactivity for sulfide oxidations was observed. In this study, chromium(III) salen complexes effectively catalyzed the oxidation of aryl sulfides into sulfoxides with PhI(OAc)2 in the presence of a small amount of water. The competition product studies with the Hammett correlation plot indicated that the observed chromium(V)-oxo species is not likely to serve as the major oxidant for the sulfide oxidations catalyzed by chromium(III) salens with PhI(OAc)2.
Chemistry of Oxaziridines. 10. Selective Catalytic Oxidation of Sulfides to Sulfoxides Using N-Sulfonyloxaziridines
Davis, Franklin A.,Lal, Sankar G.,Durst, H. Dupont
, p. 5004 - 5007 (1988)
The chemoselective catalytic oxidation of aliphatic and aromatic sulfides to sulfoxides (90-95percent) using a buffered potassium peroxymonosulfate (Oxone) generated N-sulfonyloxaziridine is described.This oxidizing system is rapid and relatively intensitive to the reaction parameters and the structure of the sulfide.
Hybrid catalysts of molybdovanadophosphoric acid and g-C3N4with tunable bandgaps
Cai, Linkun,Hu, Jie,Li, Mu,Yin, Panchao
, p. 10724 - 10728 (2020)
The integration of semiconductors and polyoxometalates provides promising benefits for the rational tuning of hybrid materials' electronic band structures; however, the intrinsic influence of certain hybridization approaches on the resulting bandgaps of their complexes has seldom been noted. Herein, graphitic carbon nitride and a series of phosphovanadomolybdates (H3+xPMo12-xVxO40, x = 0-3) have been complexed through electrostatic charge attraction, and their optical and electronic properties are fully explored to investigate the effect of minor variations of the polyoxometalate structures on the hybrid bandgaps and electronic structures. The conduction band edge of the hybrids increases along with the expansion of the number of vanadium centers in the phosphovanadomolybdate, providing potential guidance for the design of hybrid catalysts. This journal is
Keggin-type polyacid clusters on apatite: Characteristic catalytic activities in solvent-free oxidation
Ichihara, Junko,Yamaguchi, Shunro,Nomoto, Takuya,Nakayama, Hirokazu,Iteya, Katsuma,Naitoh, Nozomu,Sasaki, Yoh
, p. 8231 - 8234 (2002)
We found that Keggin-type phosphometalates are effective catalysts for solvent-free oxidation with urea-H2O2 by dispersing on fluorapatite solid phase. In the solid phase system the phosphomolybdate (NH4)3PMo12O40 was more effective than the phosphotungstate (NH4)3PW12O40, whereas the latter was much superior to the former in the liquid-phase reaction with aqueous H2O2. In situ formation of novel peroxo-type species from (NH4)3PMo12O40/FAp and urea-H2O2, which may lead to the high catalytic activity in the solid phase system, was observed by 31P solid-state NMR.
Organophosphonate-Functionalized Lanthanopolyoxomolybdate: Synthesis, Characterization, Magnetism, Luminescence, and Catalysis of H2O2-Based Thioether Oxidation
Wang, Jiawei,Niu, Yanjun,Zhang, Meng,Ma, Pengtao,Zhang, Chao,Niu, Jingyang,Wang, Jingping
, p. 1796 - 1805 (2018)
A novel class of organophosphonate-based polyoxomolybdate derivatives, K4H5[Ln3(H2O)14{(Mo8O24)(O3PCH2COO)3}2]·23H2O (Ln = Gd (1Gd), Tb (2Tb), Dy (3Dy)), have been fully investigated by a few characterization methods such as single-crystal X-ray crystallography, XRPD, elemental analysis, TGA, and IR spectra. The magnetic properties of 1Gd, 2Tb, and 3Dy were investigated, as well as the solid-state luminescence properties of 2Tb and 3Dy. The catalysis properties of 1Gd, 2Tb, and 3Dy for thioether oxidization have been investigated using hydrogen peroxide (H2O2) as an oxidant. The catalysis study demonstrated the efficient and selective conversion of various thioethers to their corresponding sulfones in excellent yields.
Synthesis and characterization of a Sb(v)-containing polyoxomolybdate serving as a catalyst for sulfoxidation
Lu, Jingkun,Wang, Yaping,Ma, Xinyi,Niu, Yanjun,Singh, Vikram,Ma, Pengtao,Zhang, Chao,Niu, Jingyang,Wang, Jingping
, p. 8070 - 8077 (2018)
A Sb-containing Anderson-based polyoxomolybdate cluster, [(CH3)4N]4H8[Na5Sb3(Sb2Mo12O57)]·17H2O [1; (CH3)4N+ = TMA+], has been successfully synthesized by using an aqueous solution method and structurally characterized. In particular, UV-Vis spectroscopy has been employed to elucidate the stability of the polyoxoanions. Under mild conditions, the catalyst demonstrates high activity and selectivity for the sulfoxidation of various sulfides in the presence of hydrogen peroxide. For example, thioanisole undergoes up to 100% conversion and 100% sulfone selectivity at 25 °C in aqueous solution.
Spontaneous stepwise self-assembly of a polyoxometalate-organic hybrid into catalytically active one-dimensional anisotropic structures
Yin, Panchao,Bayaguud, Aruuhan,Cheng, Peng,Haso, Fadi,Hu, Lang,Wang, Joy,Vezenov, Dmitri,Winans, Randall E.,Hao, Jian,Li, Tao,Wei, Yongge,Liu, Tianbo
, p. 9589 - 9595 (2014)
An inorganic-organic hybrid surfactant with a hexavanadate cluster as the polar head group was designed and observed to assemble into micelle structures, which further spontaneously coagulate into a 1D anisotropic structure in aqueous solutions. Such a hierarchical self-assembly process is driven by the cooperation of varied noncovalent interactions, including hydrophobic, electrostatic, and hydrogen-bonding interactions. The hydrophobic interaction drives the quick formation of the micelle structure; electrostatic interactions involving counterions leads to the further coagulation of the micelles into larger assemblies. This process is similar to the crystallization process, but the specific counterions and the directional hydrogen bonding lead to the 1D growth of the final assemblies. Since most of the hexavanadates are exposed to the surface, the 1D assembly with nanoscale thickness is a highly efficient heterogeneous catalyst for the oxidation of organic sulfides with appreciable recyclability. Surfing hybrids: Inorganic-organic hybrid surfactant with hexavanadate as the polar head group was programmed to assemble into a 1D structure with the cooperation of hydrophobic, electrostatic, and hydrogen-bonding interactions (see figure); these last interactions are directional and lead to the anisotropic assemblies. The nanobelts were highly efficient heterogeneous catalysts for oxidation of organic sulfides because most of the hexavanadates are exposed onto the surface.
