14265-44-2Relevant academic research and scientific papers
Active agents in heterogeneous photocatalysis: Atomic oxygen species vs. OH. radicals: Related quantum yields
Herrmann, Jean-Marie
, p. 2731 - 2750 (2001)
After a general survey of the fundamental characteristics of heterogeneous photocatalysis, the present article classifies the ensemble of reactions into three major categories: i) mild oxidations, ii) total oxidations, and iii) reactions involving hydrogen. Depending on the presence or absence of H2O, the active oxidizing species will be either a dissociated neutral oxygen species, denoted as O*, which is present in anhydrous systems and responsible for selective mild oxidation reactions, or an OH. radical, formed in the presence of H2O and responsible for totally degradative oxidation reactions. The existence of O* species is substantiated by photoconductivity measurements, oxygen-isotope exchange, and reactions in which oxygen-free NO is the oxidizing agent. The influence of the five main parameters that govern kinetics experiments i) the mass of the catalysts, ii) the wavelength, iii) the concentrations or partial pressures of reactants, iv) the temperature, and v) the radiant flux is examined to determine the best conditions for obtaining the optimum photocatalytic quantum yield (PQY), the definition of which is based on the quantum yield given in [1] for photochemistry.
Kinetics of the Base Decomposition of Dodecatungstophosphate(3-) in Weakly Alkaline Solutions
Kyle, James H.
, p. 2609 - 2612 (1983)
The kinetics of the decomposition of 3- (1.5 x 10-5 mol dm-3) to 2- and 3- has been studied in the range pH 7-9 at an ionic strength of 0.1 mol dm-3.The reaction proceeds
Sectroscopic study of stability and molecular species of 12-tungstophosphoric acid in aqueous solution
Holclajtner-Antunovic, Ivanka,Bajuk-Bogdanovic, Danica,Todorovic, Marija,Mioc, Ubavka B.,Zakrzewska, Joanna,Uskokovic-Markovic, Snezana
, p. 996 - 1004 (2008)
The various molecular species of 12-tungstophosporic acid (WPA) in aqueous solutions of different pH values (from 1 to 11.5) were investigated by UV, IR, and NMR spectroscopy. The dependence of the attained equilibrium composition in solution on time, con
Synthesis, characterization of a ternary Cu(II) Schiff base complex with degradation activity of organophosphorus pesticides
Li, Xin,Zhang, Dandan,Liu, Zihui,Xu, Ying,Wang, Dongfeng
, p. 280 - 289 (2018)
Organophosphorus pesticides are a class of the most important groups of insecticides and are widely applied to pest and plant diseases control in agriculture. The extensive application of organophosphorus pesticides can subsequently release organophosphorus pesticides into environment which may pose a seriously adverse impact to non-target organisms and humans. However, we could not ban organophosphorus pesticides at present as they are very efficient. Therefore, the new technique of degradation of organophosphorus pesticides must be studied. In this paper, a ternary copper Schiff base complex 2Cu(C14H8NO3Cl)(C12H8N2)·3CH3OH was synthesized and characterised by physico-chemical and spectroscopic methods. The degraded effects of 4 pesticides by the complex were investigated. The results showed that the degraded rates of every organophosphorus pesticide were increased. However, the effects of degradation were varied because of the different molecule structures of organophosphorus pesticides. Gas chromatography-mass spectrometry (GC–MS) and ion chromatography were used to analyze the degradation products by the complex, and then the catalytic mechanism of degradation was proposed. The study results suggest that the Schiff base copper complex, as a potent catalyzer, may find its applications in catalytic degradation area.
Aqueous speciation studies of europium(III) phosphotungstate
Zhang, Cheng,Howell, Robertha C.,Scotland, Kymora B.,Perez, Frances G.,Todaro, Louis,Francesconi, Lynn C.
, p. 7691 - 7701 (2004)
The incorporation of lanthanide ions into polyoxometalates may be a unique approach to generate new luminescent, magnetic, and catalytic functional materials. To realize these new applications of lanthanide polyoxometalates, it is imperative to understand the solution speciation chemistry and its impact on solid-state materials. In this study we find that the aqueous speciation of europium(III) and the trivacant polyoxometalate, PW9O 349-, is a function of pH, countercation, and stoichiometry. For example, at low pH, the lacunary (PW11O 39)7- predominates and the 1:1 Eu(PW11O 39)4-, 2, forms. As the pH is increased, the 1:2 complex, Eu(PW11O39)211- species, 3, and (NH4)22{(Eu2PW10O38) 4(W3O8(H2O)2(OH) 4}·44H2O, a Eu8 hydroxo/oxo cluster, 1, form. Countercations modulate this effect; large countercations, such as K + and Cs+, promote the formation of species 3 and 1. Addition of Al(III) as a counterion results in low pH and formation of {Eu(H2O)3(α-2-P2W17O 61)}2, 4, with Al(III) counterions bound to terminal W-O bonds. The four species observed in these speciation studies have been isolated, crystallized, and characterized by X-ray crystallography, solution multinuclear NMR spectroscopy, and other appropriate techniques. These species are 1, (NH4)22{(Eu2PW10O38) 4(W3O8(H2O)2(OH) 4}·44H2O (P1; a = 20.2000(0), b = 22.6951-(6), c = 25.3200(7) A; α = 65.6760(10), β = 88.5240(10), γ = 86.0369(10)°; V = 10550.0(5) A3; Z = 2), 2, Al(H 3O){Eu(H2O)2PW11O 34}·20H2O (P1, a = 11.4280(23), b = 11.5930(23), c = 19.754(4) A; α = 103.66(3), β = 95.29(3), γ = 102.31(3)°; V = 2456.4(9) A3; Z = 2), 3, Cs 11Eu(PW11O34)2·28H 2O (P1; a = 12.8663(14), b = 19.8235(22), c = 21.7060(23) A; α = 114.57(0), β = 91.86(0), γ = 102.91(0)°; V = 4858.3(9) A3; Z = 2), 4, Al2(H3O) 8{Eu(H2O)3(α-2-P2W 17O61)}2·29H2O (P1; a = 12.649(6), b = 16.230(8), c = 21.518(9) A; α = 11.1.223(16), β = 94.182(18), γ = 107.581(17)°; V = 3842(3) A;3; Z = 1).
Studies on polyoxo and polyperoxo-metalates: Part 7. Lanthano- and thoriopolyoxotungstates as catalytic oxidants with H2O2 and the X-ray crystal structure of Na8[ThW10O36]·28H2O
Griffith, William P.,Morley-Smith, Neil,Nogueira, Helena I.S.,Shoair, Abdel G.F.,Suriaatmaja, Maria,White, Andrew J.P.,Williams, David J.
, p. 146 - 155 (2000)
The effectiveness of salts of [LnIIIW10O36]9- (Ln = Y, La, Ce, Pr, Sm, Eu, Gd, Dy, Er, Lu) and [MIVW10O36]8- (M = Ce, Th) as catalysts with H2O2
Oxidation Studies with Peroxomonophosphoric Acid. III. A Kinetic and Mechanistic Study of Oxidation of Dialkyl Sulfides
Panigrahi, Ganesh Prasad,Panda, Radhasyam
, p. 2366 - 2370 (1980)
The kinetics of oxidation of dialkyl sulfides by peroxomonophosphate in aqueous medium at 308 K and μ= 0.4 mol dm-3 follow the rate expressions (i) -d/dt= 1(H2PO51-)+k2(HPO52-)> in the pH region 6.8-8.7 where k1 and k2 values are 336.5 and 0.95, 69.7 and 0.254, and 27.5 and 0.126 dm3 mol-1 s-1 for dimethyl, diethyl and dipropyl sulfides, respectively, (ii) -d/dt= k2(HPO52-)* in the pH region 8.5-12.5, where the average k2 values are 0.86, 0.247, and 0.128 dm3 mol-1 s-1 for dimethyl, diethyl, and dipropyl sulfides, respectively, and (iii) -d(peroxomonophosphate)/dt= 2(HPO52-)+k3*(PO53-)> in the pH region 12.5-13.7, the k2 and k3 values being 0.947 and 0.107, and 0.233 and 0.018 dm3 mol-1 s-1 for dimethyl, and diethyl sulfides, respectively.The mechanism of the reaction is in line with a nucleophilic attack of the sulfide-sulfur on the peroxo oxygen, giving rise to SN2-type transition states which undergo oxygen-oxygen bond fission to give the corresponding sulfoxide and phosphate.
Mechanistic information from pressure acceleration of hydride formation via proton binding to a cobalt(I) macrocycle
Fujita, Etsuko,Wishart, James F.,Van Eldik, Rudi
, p. 1579 - 1583 (2002)
The effect of pressure on proton binding to the racemic isomer of the cobalt(I) macrocycle, CoL+ (L = 5,7,7,12.-14, 14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene), has been studied for a series of proton donors using pulse radiolysis techniques. The second-order rate constants for the reaction of CoL+ with proton donors decrease with increasing pKa of the donor acid, consistent with a reaction occurring via proton transfer. Whereas the corresponding volumes of activation (ΔV?) are rather small and negative for all acids (proton donors) with pKa values below 8.5, significantly larger negative activation volumes are found for weaker acids (pKa> 9.5) containing OH groups as proton donors. In the latter case, the observed ΔV? for these protonation reactions show a correlation with the reaction volumes (ΔV°ion) for the ionization of the weak acids with a slope of 0.44, indicating that bond dissociation of the weak acid molecule bound to the metal center proceeds approximately halfway at the transition state along the reaction coordinate in terms of volume changes.
Intrinsic Apyrase-Like Activity of Cerium-Based Metal–Organic Frameworks (MOFs): Dephosphorylation of Adenosine Tri- and Diphosphate
Gu, Jinlou,Li, Chunzhong,Li, Ke,Yang, Jian
supporting information, p. 22952 - 22956 (2020/10/23)
Apyrase is an important family of extracellular enzymes that catalyse the hydrolysis of high-energy phosphate bonds (HEPBs) in ATP and ADP, thereby modulating many physiological processes and driving life activities. Herein, we report an unexpected discovery that cerium-based metal–organic frameworks (Ce-MOFs) of UiO-66(Ce) have intrinsic apyrase-like activity for ATP/ADP-related physiological processes. The abundant CeIII/CeIV couple sites of Ce-MOFs endow them with the ability to selectively catalyse the hydrolysis of HEPBs of ATP and ADP under physiological conditions. Compared to natural enzymes, they could resist extreme pH and temperature, and present a broad range of working conditions. Based on this finding, a significant inhibitory effect on ADP-induced platelet aggregation was observed upon exposing the platelet-rich plasma (PRP) to the biomimetic UiO-66(Ce) films, prefiguring their wide application potentials in medicine and biotechnology.
Geochemical Sources and Availability of Amidophosphates on the Early Earth
Gibard, Clémentine,Gorrell, Ian B.,Jiménez, Eddy I.,Kee, Terence P.,Pasek, Matthew A.,Krishnamurthy, Ramanarayanan
supporting information, p. 8151 - 8155 (2019/05/16)
Phosphorylation of (pre)biotically relevant molecules in aqueous medium has recently been demonstrated using water-soluble diamidophosphate (DAP). Questions arise relating to the prebiotic availability of DAP and other amidophosphosphorus species on the early earth. Herein, we demonstrate that DAP and other amino-derivatives of phosphates/phosphite are generated when Fe3P (proxy for mineral schreibersite), condensed phosphates, and reduced oxidation state phosphorus compounds, which could have been available on early earth, are exposed to aqueous ammonia solutions. DAP is shown to remain in aqueous solution under conditions where phosphate is precipitated out by divalent metals. These results show that nitrogenated analogues of phosphate and reduced phosphite species can be produced and remain in solution, overcoming the thermodynamic barrier for phosphorylation in water, increasing the possibility that abiotic phosphorylation reactions occurred in aqueous environments on early earth.
