- Production of potentially prebiotic condensed phosphates by phosphorus redox chemistry
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Bringing phosphorus to life: The prebiotic origin of key biomolecules such as RNA and ATP is contingent on a source of condensed phosphates, such as pyrophosphate and triphosphate. Condensed phosphates can be produced at high yields from the oxidation of H-phosphonate or H-phosphinate. Reactive phosphates were likely abundant on the early earth's surface, setting the stage for prebiotic chemistry that led to the evolution of life. (Figure Presented).
- Pasek, Matthew A.,Kee, Terence P.,Bryant, David E.,Pavlov, Alexander A.,Lunine, Jonathan I.
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p. 7918 - 7920
(2009/04/12)
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- Temperature-Dependent Anioinic Composition of the H3PO4-CO(NH2)2-H2O System: Effect of Inorganic Salts
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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
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p. 293 - 296
(2008/10/08)
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- Synthesis of hexaphosphate by hydrolysis of cyclo-hexaphosphate
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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
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p. 387 - 394
(2007/10/03)
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- Outer-sphere redox reactions of [CoIII(NH3)5(HxPyO z)](m-3)- complexes. A temperature- and pressure-dependence kinetic study on the influence of the phosphorus oxoanions
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Outer-sphere redox reactions between [CoIII(NH3)5(HxPyO z)](m-3)- (HxPyOzm- = H2PO2-, H2PO3-, HPO32-, HP2O73-, P2O74-, γ-H2P3O103-, -HP3O104-, -P3O105-, β-H3P3O102-, -H2P3O103-, -HP3O104- or -P3O105-) and [Fe(CN)6]4- have been studied as a function of pH, HxPyOzm- oxoanion, temperature and pressure. The effect of the oxidation state, size, geometry and extent of protonation of the HxPyOzm- oxoanions on the precursor-complex formation constant, electron-transfer rate constant, and thermal and pressure activation parameters has been investigated. The values obtained indicate that all the precursor-complex formation equilibrium constants, KOS, are the same except for the non-linear β-H3P3O102-, -H2P3O103-, -HP3O104- and -P3O105- oxoanions, where the values are consistently larger, indicating that hydrogen bonding plays a very important role. The electron-transfer rate constant for a series of [Co(NH3)5(HxPyOz)] (m-3)-, with linear oxoanions, increases on decreasing the negative charge on the complex {k308 = 0.73 × 10-3 and (8.5-11) × 10-3 s-1 for the γ-[Co(NH3)5(P3O10)] 2- and γ-[Co(NH3)5(H2P3O 10)], respectively}. For the non-linear β-P3O105- oxoanions a threshold is observed when the external oxo groups are protonated {k308 = 20 × 10-3 for β-[Co(NH3)5(H3P3O 10)]+ species and 0.84 × 10-3 s-1 for β-[Co(NH3)5(H2P3O 10)], -[Co(NH3)5(HP3O10)]- or -[Co(NH3)5(P3O10)]2-}. The ΔH? values are within the range expected, while those of ΔS? and ΔV? vary considerably with the extent of protonation of the phosphorus oxoanionic ligands, being 13 J K-1 mol-1 and +36 cm3 mol-1 and 69 J K-1 mol-1 and +13 cm3 mol-1, respectively for the [Co(NH3)5(HP2O7)]-[Co(NH 3)5(P2O7)]- couple. The ΔV? values depend strongly on the oxo group distribution of the oxophosphorus ligand {+ 13 and + 32 cm3 mol-1 for β- and γ-[Co(NH3)5(P3O10)] 2-, respectively}. Hydrogen bonding and solvent reorganization play a key role in the interpretation of the activation parameters.
- Martinez, Manuel,Pitarque, Mari-Angel,Van Eldik, Rudi
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p. 2665 - 2671
(2007/10/03)
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- Ueber die Reaktion von Harnstoff mit Ammoniumhydrogenamidophosphat unter dem Atmosphaerendruck
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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
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p. 3613 - 3616
(2007/10/02)
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- NUCLEAR MAGNETIC RESONANCE, CRYSTALLOGRAPHIC, AND HYDROLYTIC STUDIES OF THE beta - AND gamma -COORDINATION ISOMERS OF PENTAAMMINE(DIHYDROGEN TRIPHOSPHATO)COBALT(III) MONOHYDRATE.
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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
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p. 2812 - 2818
(2007/10/02)
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- The preparation and properties of the twelve-membered ring hexametaphosphate anion
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A true hexametaphosphate anion was prepared and some of its physical properties were measured. The hydrolysis rates for the ring opening to sodium hexapolyphosphate were determined at 30 and 60° at pH values of 4, 7, and 11. X-Ray powder patterns were obtained for the following salts: Na6P6O18, Na6P6O18·6H2O, Li6P6O18, and Li6P6O18·6H2O.
- Griffith,Buxton
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p. 549 - 551
(2008/10/08)
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