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Active agents in heterogeneous photocatalysis: Atomic oxygen species vs. OH. radicals: Related quantum yields
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.
Herrmann, Jean-Marie
p. 2731 - 2750
(2001)
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Kinetics of the Base Decomposition of Dodecatungstophosphate(3-) in Weakly Alkaline Solutions
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
Kyle, James H.
p. 2609 - 2612
(1983)
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Sectroscopic study of stability and molecular species of 12-tungstophosphoric acid in aqueous solution
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
Holclajtner-Antunovic, Ivanka,Bajuk-Bogdanovic, Danica,Todorovic, Marija,Mioc, Ubavka B.,Zakrzewska, Joanna,Uskokovic-Markovic, Snezana
p. 996 - 1004
(2008)
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Synthesis, characterization of a ternary Cu(II) Schiff base complex with degradation activity of organophosphorus pesticides
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.
Li, Xin,Zhang, Dandan,Liu, Zihui,Xu, Ying,Wang, Dongfeng
p. 280 - 289
(2018)
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Aqueous speciation studies of europium(III) phosphotungstate
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).
Zhang, Cheng,Howell, Robertha C.,Scotland, Kymora B.,Perez, Frances G.,Todaro, Louis,Francesconi, Lynn C.
p. 7691 - 7701
(2004)
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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
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
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)
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Oxidation Studies with Peroxomonophosphoric Acid. III. A Kinetic and Mechanistic Study of Oxidation of Dialkyl Sulfides
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.
Panigrahi, Ganesh Prasad,Panda, Radhasyam
p. 2366 - 2370
(1980)
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Mechanistic information from pressure acceleration of hydride formation via proton binding to a cobalt(I) macrocycle
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.
Fujita, Etsuko,Wishart, James F.,Van Eldik, Rudi
p. 1579 - 1583
(2002)
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Intrinsic Apyrase-Like Activity of Cerium-Based Metal–Organic Frameworks (MOFs): Dephosphorylation of Adenosine Tri- and Diphosphate
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.
Gu, Jinlou,Li, Chunzhong,Li, Ke,Yang, Jian
supporting information
p. 22952 - 22956
(2020/10/23)

Degradation of tri(2-chloroisopropyl) phosphate by the UV/H2O2 system: Kinetics, mechanisms and toxicity evaluation
A photodegradation technology based on the combination of ultraviolet radiation with H2O2 (UV/H2O2) for degrading tri(chloroisopropyl) phosphate (TCPP) was developed. In ultrapure water, a pseudo-first order reaction was observed, and the degradation rate constant reached 0.0035 min?1 (R2 = 0.9871) for 5 mg L?1 TCPP using 250 W UV light irradiation with 50 mg L?1 H2O2. In detail, the yield rates of Cl? and PO43? reached 0.19 mg L?1 and 0.58 mg L?1, respectively. The total organic carbon (TOC) removal rate was 43.02%. The pH value of the TCPP solution after the reaction was 3.46. The mass spectrometric detection data showed a partial transformation of TCPP into a series of hydroxylated and dechlorinated products. Based on the luminescent bacteria experimental data, the toxicity of TCPP products increased obviously as the reaction proceeded. In conclusion, degradation of high concentration TCPP in UV/H2O2 systems may result in more toxic substances, but its potential application for real wastewater is promising in the future after appropriate optimization, domestication and evaluation.
He, Huan,Ji, Qiuyi,Gao, Zhanqi,Yang, Shaogui,Sun, Cheng,Li, Shiyin,Zhang, Limin
(2019/07/31)

Geochemical Sources and Availability of Amidophosphates on the Early Earth
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.
Gibard, Clémentine,Gorrell, Ian B.,Jiménez, Eddy I.,Kee, Terence P.,Pasek, Matthew A.,Krishnamurthy, Ramanarayanan
supporting information
p. 8151 - 8155
(2019/05/16)

Solvothermal preparation of Ag nanoparticle and graphene co-loaded TiO2 for the photocatalytic degradation of paraoxon pesticide under visible light irradiation
The growing use of organophosphorus compounds such as paraoxon as agriculture pesticides results in their accumulation in soils and groundwater. Therefore there is a high demand for developing efficient methods for removing these materials from contaminated environmental resources. In this study, Ag nanoparticle and graphene co-loaded TiO2 with various contents of Ag and graphene was prepared via a facile surfactant free solvothermal method in a mixture of water and ethanol solvents and was applied, for the first time, for the photocatalytic degradation of paraoxon (as a model organophosphorus compound) under visible light irradiation. In this ternary nanocomposite, the presence of Ag nanoparticles is for narrowing the band gap to the visible region due to its surface plasmon resonance (SPR) effect and the presence of graphene is for diminishing the recombination rate of the photogenerated electron and holes due to its high electrical conductivity. The results of photocatalytic activity tests demonstrate that the nanocomposite with 6% wt Ag and 1% wt graphene content has the best photocatalytic activity among the products. Investigation of the chemical state of the nanocomposites showed that the covering of Ag nanoparticle loaded TiO2 with a high weight ratio of graphene resulted in the formation of Ag-O bonds through bonding of Ag to the oxygen functional groups of graphene which causes a decrease of the SPR effect of Ag and by this way decreases the photocatalytic activity. Gas Chromatography-Mass Spectrometry (GC-MS) was used as analytical tool for determination of the photocatalytic reaction intermediates. GC-MS analysis results show that photodegradation of paraoxon produces 4-nitrophenol, di-ethylphosphate, mono-ethylphosphate, hydroquinone and hydroxyhydroquinone as major intermediates and subsequent photodegradation of these results in complete mineralization of paraoxon.
Keihan, Amir Homayoun,Hosseinzadeh, Reza,Farhadian, Mousa,Kooshki, Hamid,Hosseinzadeh, Ghader
p. 83673 - 83687
(2016/11/05)

PROCESS FOR OXIDATION OF N-(PHOSPHONOMETHYL)IMINODIACETIC ACID
An oxidation catalyst is prepared by pyrolyzing a source of iron and a source of nitrogen on a carbon support. Preferably, a noble metal is deposited over the modified support which comprises iron and nitrogen bound to the carbon support. The catalyst is effective for oxidation reactions such as the oxidative cleavage of tertiary amines to produce secondary amines, especially the oxidation of N-(phosphonomethyl)iminodiacetic acid to N-(phosphonomethyl)-glycine.
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(2015/11/10)

Titrage infrarouge de l'acide phosphorique
The titration of phosphoric acid by sodium hydroxide was performed by infrared (IR) spectroscopy with the objective of obtaining the infrared spectra of the pure ionic species and determining their abundance as a function of pH. In the series of spectra, taken in the pH range of 0.18-13.4, the subtraction of neutral water, acidic water, and basic water was made. Factor analysis (FA) was then applied to the series of spectra to obtain the objective. First, we found the four most abundant species: H3PO4 (pH 0-4), H2PO4- (pH 0-9), HPO4-2 (pH 4-14), and PO4-3 (pH 9-14). Secondly, we found three complexes in small quantities: H3PO4-H2PO4- (pH 0-4), H2PO4--HPO4-2 (pH 4-9), and HPO4-2-PO4-3 (pH 9-14). The equilibrium constants of these species with the parent molecules are 0.65, 0.63, and 0.4 L/mol, respectively. Thirdly, we found residual water that was closely bound to the ionic species which formed hydrates. The pKa values obtained from the IR titration were used to obtain the theoretical concentration of the four principal species as a function of pH. The resulting distribution curve was found to be coincident with the distribution curve obtained by IR.
Baril, Jocelyn,Max, Jean-Joseph,Chapados, Camille
p. 490 - 507
(2007/10/03)

Chemometrics on thermochromatography of inorganic salts: Decomposition of thermochromatograms to chromatograms and thermograms using EFA and peak shape constraints
A low volume thermal furnace, interfaced to a capillary gas chromatograph (GC) via a computer controlled, pneumatic sample inlet device, permits temperature resolved high speed GC analysis of the evolved components. The method is called thermochromatography (ThGC). The results of such an evolved gas analysis (EGA) can be conveniently represented as a thermochromatogram: a two-way detector response surface in the axes of sample temperature and chromatographic retention time. It is demonstrated that such thermochromatograms, if subjected to the specific chemometrics analysis - evolving factor analysis (EFA) - provide information about independent thermal processes that happened during the sample heating. The data is decomposed to matrixes of chromatograms and thermal evolution curves, thermograms, in a manner which connects each thermal decomposition step to the products evolved at that temperature region. Chromatographic peak shapes of the evolved gases are used as additional constraints in the analysis. The EFA performance is evaluated by ThGC of several inorganic salts and apatites. As a reference to EFA the direct deconvolution of thermochromatograms to the gas chromatograms and temperature dependent thermograms was performed. This comparison demonstrated that EFA gives confident results if essential constraints of non-negativity to chromatograms and thermograms have been applied.
Elomaa,Kaljurand,Koel,Kudrjashova
p. 73 - 83
(2008/10/09)

Temperature-Dependent Anioinic Composition of the H3PO4-CO(NH2)2-H2O System: Effect of Inorganic Salts
The effect of temperature and additives (zinc(II) and tin(II) salts, Na4P2O7, Na5P3O10) on the anionic composition of the H3PO4-CO(NH2)2-H2O system was studied by paper chromatography. The anionic composition is found to be governed by the kinetic competition between hydrolysis and condensation. The addition of Na4P2O7 or Na5P3O10 ensures high di- and triphosphate contents of the solutions. Tin(II) and zinc(II) catalyze the hydrolysis of polyphosphates and increase the fraction of short-chain species.
Samuskevich,Petrovskaya,Luneva
p. 293 - 296
(2008/10/08)

Evolved gas analysis of apatite materials using thermochromatography
Evolved gas analyses of model inorganic compounds and apatites are described. The measurements are performed on the system - a 'thermochromatograph' (ThGC) - with a low-volume, thermal furnace, interfaced to a capillary gas chromatograph (GC) via a computer-controlled, pneumatic sample inlet device in the 70-600°C region. The 'information content' performance of this inherently simpler system is comparable to that of TG/GC/MS and TG/GC/IR systems when similar materials are analyzed.
Koel, Mihkel,Kudrjasova, Marina,Tonsuaadu, Kaia,Peld, Merike,Veiderma, Mihkel
p. 25 - 32
(2008/10/09)

Synthesis of hexaphosphate by hydrolysis of cyclo-hexaphosphate
Sodium and ammonium hexaphosphates were prepared by hydrolyzing cyclo-hexaphosphate in a 10M sodium hydroxide solution at -7°C for 20h. Sodium hexaphosphate was amorphous and unstable at room temperature. Ammonium hexaphosphate was crystalline and stable at room temperature.
Watanabe, Makoto,Asai, Naoki,Sakurai, Makoto
p. 387 - 394
(2007/10/03)

A thermoanalytical study of synthetic carbonate-containing apatites
Two series of carbonate-apatites, Ca10(PO4)6-x(CO3)x(F,OH)2, were synthesized by precipitating them from aqueous solutions followed by ripening at the precipitation temperature (20 or 80°C). Initial solutions contained Ca(2+), Mg(2+), NH4(1+), PO4(3-), F(1-), CO3(2-) and NO3(1-) ions; in the second series Na(1+) was added. The samples had low crystallinity but, nevertheless, showed the apatite structure as judged from XRDand IR. Thermal degradation was followed by simultaneous TG/DTA and TG/ EGA (evolved gas analysis) methods and by ex situ studies. The NH4(1+) containing samples (A, 20°C and B, 80°C) and two Na(1+)-containing samples (C and D, both at 80°C) were subjected to a detailed study. On the basis of EGA studies of sample A by FTIR, the first two exothermic peaks at 250-300°C could be assigned to the release of H2O and H2O + NH3, respectively: the remaining three at 350-710°C were due to CO2 evolution and changes in the apatite structure. For samples synthesized at 80°C, the DTA peaks were smaller than for sample A. The EGA peak due to NH3 was missing for Na(1+)-containing samples (C and D). For all samples, the residue at 1000°C had the hydroxy-fluorapatite structure. The TA and XRD data indicate that the crystal structure of the precipitated apatites is relatively labile. After the release of volatiles, however, thermally induced rearrangements take place leading to a more stable and crystalline phase.
Tonsuaadu, K.,Peld, M.,Leskelae, T.,Mannonen, R.,Niinistoe, L.,Veiderma, M.
p. 55 - 66
(2008/10/09)

Contributions to the Chemistry of Phosphorus. 237. On the Reaction of Diphosphane(4) with Peroxo Compounds: Formation of Phosphinophosphinic Acid, H2PPH(O)OH, and Bis(phosphino)phosphinic Acid, (H2P)2P(O)OH
Diphosphane(4) reacts with peroxo compounds such as hydrogen peroxide, tetraline hydroperoxide, trifluoroperoxyacetic acid, and cumene hydroperoxide (which is particularly suited for preparative work) at -30°Cto furnish phosphinophosphinic acid, H2PP(O)OH (1), as the primary prod uct. Compound 1 disproportionates to a major extent in statu nascendi togive phosphanes (above all PH3) and monophosphorus acids of various oxi dation states as well as some bis(phosphino)phosphinic acid, (H2P)2P(O)OH (2). The acids 1 and 2 can be trapped and stabilized as their triethylammonium salts. The structures of these salts have been determined by spectroscopic investigations.
Baudler, M.,Heumueller, H.
(2008/10/08)

Polyoxometalate - Diphosphate complexes. 3. Possible intermediates in the molybdate-catalyzed hydrolysis of pyrophosphate. The structure of hexamolybdomethylenediphosphonate, [(O3PCH2PO3)Mo6O18(H 2O)4]4-
Two new polyoxomolybdate-diphosphate complexes with the formula [(O3PXPO3)Mo6O18(H 2O)4]4- (I, X = CH2; II, X = O) have been synthesized and characterized by 31P-, 13C-, 1H-NMR, IR, and elemental analysis. Anions I and II are formed under weakly acidic conditions (pH 3-3.5). An X-ray structure determination was carried out on Cs4[(O3PCH2PO3)Mo6O 18(H2O)4]·7H2O, which crystallizes in the triclinic system, space group P1, with a = 11.301(2) A?, b = 11.499(3) A?, c = 16.024(4) A?, α = 98.43°, β = 107.92°, γ = 106.61°, V = 1834.7(7) A?3, Z = 2, and ρcalcd = 3.152 g/cm3. Structural analysis based on 9312 independent reflections leads to a solution, R = 6.51% (I > 2σ(I)). Anion I consists of a six-membered ring of MoO6 octahedra, which alternate in sharing edges and corners. The [O3PCH2PO3]4- anion is bound with P(2) in the center of the ring and P(1) off-center and bound above the ring to two adjacent MoO6 octahedra. Each of the remaining four molybdenums has a terminal water ligand on the same side of the ring as P(1). Anion II almost certainly has an analogous structure based on spectroscopic evidence. A second polyoxomolybdate-pyrophosphate complex with a [O3POPO3]4-: MoO3 ratio of 1:3 has been synthesized at pH 6. This complex and anion II are possible intermediates in the molybdate-catalyzed hydrolysis of pyrophosphate which is known to be most effective at pH 2 with a secondary maximum at pH 5.5.
Kortz, Uli,Pope, Michael T.
p. 2160 - 2163
(2008/10/08)

Molecular recognition of phosphite and phosphate by the cobalt(II)-OBISDIEN system and oxidation of phosphite to phosphate by coordinated molecular oxygen
Potentiometric equilibrium studies were carried out to determine the degree of binding of phosphite and phosphate ions with various protonated forms of OBISDIEN, 1,4,7,13,16,19-hexaaza-10,22-dioxacyclotetracosane, with its cobalt 1:1 and 2:1 M:L complexes and with the protonated chelates. The dioxygen affinity of the μ-phosphitodicobalt(II)-OBISDIEN complex was determined. Kinetic studies at pH 8 and pH 9 were carried out at 60, 70, and 80°C to measure the rate of degradation of the OBISDIEN-dicobalt-dioxygen-μ-phosphito complex. The phosphate ion produced was identified through 31P NMR and by an 18O-tracer experiment.
Motekaitis, Ramunas J.,Martell, Arthur E.
p. 1032 - 1037
(2008/10/08)

A flash photolysis study of the oxidation of aliphatic amines by phosphate radical
Rate constants for the reaction of the phosphate radical (PO42-) with various aliphatic amines have been measured by flash kinetic spectrophotometry.Phosphate radical can react with aliphatic amines by hydrogen atom abstraction or electron transfer, the general reactivity order being tertiary secondary primary.For tertiary amines, a good correlation has been obtained when the logarithm of rate constants are plotted against the oxidation peak potentials of the amines, providing clear evidence for an electron transfer mechanism.In the case of tertiary amines, electron transfer from the nitrogen takes place.The identification of aminium cation radicals in the case of cyclic tertiary amines like, 1,4-diazabicyclooctane (DABCO) and 1,3,6,8-tetraazatricyclododecane (TATCD) provides additional proof for electron transfer.Primary and secondary amines get oxidized mainly by hydrogen atom abstraction as shown by the poor correlation with Taft substituent constants, but electron transfer cannot be completely ruled out.In the case of t-butylamine, electron transfer takes place and t-butylalcohol has been identified as the end product.
Subramanian, P,Rajaram, J,Ramarkrishnan, V,Kuriacose, J C
p. 913 - 919
(2007/10/02)

Oxidative Conversion of Diphosphonate to Diphosphate and Isohypophosphate by Hydrogen Peroxide
Diphosphonate (oxidation number of phosphorus +3) could be oxidized by hydrogen peroxide without P-O-P bond cleavage.The formation of dimeric compounds; diphosphate (oxidation number +5) and isohypophosphate (oxidation numbers +3 and +5), was characterize
Yoza, Norimasa,Tokushige, Noriko,Nakazato, Tetsuya,Takehara, Ko,Ide, Yasushi,Baba, Yoshinobu
p. 1487 - 1490
(2007/10/02)

CONDENSATION AND DECOMPOSITION OF HYDRATED ALKALINE EARTH BIS(HYDROGENPHOSPHORAMIDATES) WITH ACIDS
Alkaline earth bis(hydrogenphosphoramidates) were made by the wet process.The phosphoramidates reacted with hydrogen chloride, acetic acid, and oxalic acid to form ortho- and polyphosphates without producing imidopolyphosphates.For the degradation and polymerization, water was considered to play a very important role and the following reaction seemed to be the first step: where M stands for an alkaline earth cation.Key words: Phosphoramidate, Condensation, Decomposition, Hydrolysis Phosphorus-Nitrogen Compound, Alkaline Earth, Polyphosphate
Sato, Shoji,Watanabe, Makoto
p. 1 - 10
(2007/10/02)

Decomposition of O-Phosphoserine Accelerated by Copper(II) Complexes
The decomposition of O-phosphoserine accelerated by the formation of ternary copper(II) complexes with other bidentate ligands has been kinetically investigated in aqueous solutions.The reaction was assigned to a β-elimination and the observed rate constant was expressed as a linear function of .
Murakami, Tasuku
p. 2065 - 2068
(2007/10/02)

Ueber die Reaktion von Harnstoff mit Ammoniumhydrogenamidophosphat unter dem Atmosphaerendruck
Die Reaktion von Harnstoff mit Ammoniumhydrogenamidophosphat (NH4HPO3NH2) im Schmelzzustand unter dem Atmosphaerendruck ergibt, dass die Bildung des Guanidinumions (GH+) zusammen mit dem Phosphation bei ca. 160
Shimasaki, Choichiro,Hara, Mitsunari
p. 3613 - 3616
(2007/10/02)

NUCLEAR MAGNETIC RESONANCE, CRYSTALLOGRAPHIC, AND HYDROLYTIC STUDIES OF THE beta - AND gamma -COORDINATION ISOMERS OF PENTAAMMINE(DIHYDROGEN TRIPHOSPHATO)COBALT(III) MONOHYDRATE.
The linkage isomers beta -(dihydrogen triphosphato)pentaamminecobalt(III) and gamma -(dihydrogen triphosphato)pentaamminecobalt(III), left bracket Co(NH//3)//5H//2P//3O//1//0 multiplied by (times) H//2O right bracket , have been synthesized and characteri
Haromy,Gilletti,Cornelius,Sundaralingam
p. 2812 - 2818
(2007/10/02)

KINETIC STUDY ON HYDROLYSIS OF SILICON PHOSPHATE IN AQUEOUS ALKALINE SOLUTIONS.
Kinetic study of the hydrolysis of silicon phosphate, Si//3(PO//4)//4 (hexagonal), was carried out in borax buffer solutions (pH 5-12, temperature 20-50 degree C) to investigate how it acts as a hardener for alkali silicate adhesive. The silicon phosphate was found to be hydrolyzed with a resulting release of orthophosphate ion, soluble silicate ions, and colloidal silica under mild conditions; the decomposition rate increased with decreasing the particle size of the phosphate and with increasing the pH and temperature of the buffer solution.
Saeki,Narita,Naito
p. 1591 - 1595
(2007/10/02)