Phosphorus Oxyacids Research Articles

Kinetics and mechanism of the oxidation of phosphinic, phenylphosphinic and phosphorous acids by benzyltrimethylammonium dichloroiodate

Oxidation of lower phosphorus oxyacids by benzyltrimethylammonium dichloroiodate (BTACI), in the presence of zinc chloride, resulted in the formation of the corresponding oxyacids with phosphorus in a higher oxidation state. The reaction is first order with respect to the concentration of BTACI, oxyacid and zinc chloride. The reaction exhibited the presence of a substantial kinetic isotope effect. Addition of benzyltrimethylammonium chloride enhances the reaction rate. It is proposed that the reactive oxidizing species is [PhCH2Me3N]+ [Zn2Cl6]−2I+. It has been shown that the pentacoordinated tautomer of the phosphorus oxyacid is the reactive reductant. A mechanism involving a hydride-ion transfer from the P-H bond to the oxidant in the rate-determining step has been postulated.

Drying from Phosphate-Buffered Solutions Can Result in the Phosphorylation of Primary and Secondary Alcohol Groups of Saccharides, Hydroxylated Amino Acids, Proteins, and Glycoproteins

Drying (e.g., freeze-drying) aqueous phosphate-buffered solutions of organic compounds containing primary and/or secondary alcohol groups promotes esterification, producing orthophosphate esters. The reaction is accelerated by heat and by pH values < 7 and is affected by residual moisture content. The same preparations as solutions, similarly treated, produced little or no phosphorylated materials. The promotion of esterification in the dry state can, in part, be rationalized in terms of a mass-action effect because of the resulting low-water activity in dried preparations. When metaphosphates are used, esterification proceeds at a greatly increased rate and to a greater extent. Because of the relatively facile interconversion of phosphorus oxyacid salts, it is possible that a "metaphosphate species" may be responsible for the esterification reaction in all cases. We conclude that care should be exercised when hydroxylated organic compounds are dried from phosphate buffers so as to avoid the formation of phosphorylated artifacts.

The Mechanism of Phosphorus Incorporation during the Electrodeposition of Nickel‐Phosphorus Alloys

Phosphine was detected and quantified during the electrodeposition of nickel‐phosphorus alloys. The presence of supports the indirect mechanism of phosphorus incorporation: the phosphorus oxyacid in the bath is reduced to phosphine, which then undergoes a redox reaction with Ni2+ to produce both phosphorus and nickel in the elemental form. Phosphine is produced more readily from hypophosphorus acid than from phosphorus acid. Phosphine production from hypophosphorus acid is favored by low pH, and facilitated by the presence of nickelous ion. The latter effect may result from the release of hydrogen ions in the redox reaction involving and Ni2+.

Kinetics and mechanism of oxidation of phosphorus oxyacids by pyridinium hydrobromide perbromide

Oxidation of three lower oxyacids of phosphorus, viz. phosphinic, phenylphosphinic and phosphorous acids by pyridinium hydrobromide perbromide (PHPB), is first-order with respect to both oxyacid and PHPB. There is no effect on addition of acylonitrile and pyridinium bromide. On oxidation, deuterated phosphinic and phosphorous acids exhibit substantial kinetic isotope effects. The effect of solvent composition on reaction rate indicates that the transition state is more polar than the reactants. Reaction rates were determined at different temperatures and the activation parameters calculated. Alternative mechanisms, involving the two tautomeric forms of the oxyacid, have been formulated and it has been concluded that the reaction proceeds through the pentacoordinated tautomer. Transfer of a hydride ion from the oxyacid to PHPB, in the rate-determining step, has been proposed.

Kinetics of the oxidation of phosphinic, phenylphosphinic, and phosphorous acids by N‐bromoacetamide

AbstractThe oxidation of phosphinic, phenylphosphinic, and phosphorous acids by N‐bromoacetamide (NBA) in acid solution, results in the formation of corresponding higher oxyacids of phosphorus. The reaction is first order with respect to NBA, second order in the oxyacid and inverse first in hydrogen ions. The oxidation of deuteriated phosphorus oxyacids showed the presence of a substantial primary kinetic isotope effect. The reaction failed to induce polymerization of acrylonitrile. Added acetamide has no effect on the reaction rate. It has been shown that the ‘inactive’ tautomer of the phosphorus oxyacids, RHP(O)OH, participates in the oxidation process. A rate‐determining step involving transfer of a hydride ion from the PH bond to the oxidant has been proposed.

ChemInform Abstract: Computationally Studies of Open‐Shell Phosphorus Oxyacids. Part 3. Theoretical Rotation, Pseudorotation, and Pseudoinversion Barriers for the Hydroxyphosphoranyl Radical.

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ChemInform Abstract: Kinetics and Mechanism of the Oxidation of Phosphinic, Phenylphosphinic, and Phosphorous Acids by Pyridinium Fluorotrioxochromate(VI)

Oxidation of the lower phosphorus oxyacids by [C5H5NH][CrO3F] results in the formation of corresponding oxyacids in the higher valence states. The reaction is first order with respect to the oxidant concentration. A Michaelis–Menten type kinetics was observed with respect to the substrate, indicating the formation of a complex in a pre-equilibrium. The formation constants and the rates of disproportionation of the complexes have been evaluated at different temperatures. The reaction exhibits a substantial primary kinetic isotope effect. The rates in 19 different organic solvents have been analysed using Kamlet-Taft and Swain equations. It has been found that the cation-solvating power of the solvents plays an important role. It is proposed that the ‘inactive’ tautomer of the phosphorus oxyacids is the reactive reductant, and that transfer of a hydride ion from the P–H bond to the oxidant in the rate-determining step occurs.

Kinetics and Mechanism of Oxidation of Phosphinic, Phenylphosphinic, and Phosphonic Acids by Pyridinium Chlorochromate

Abstract Oxidation of the lower oxyacids of phosphorus by pyridinium chlorochromate (PCC) results in the formation of the corresponding higher oxyacids of phosphorus. The reaction is of first order with respect to PCC and the oxyacid. The reaction is catalyzed by hydrogen ions, kobs=a+b[H+]. The reaction exhibited a substantial primary kinetic isotope effect. The rates in 19 different organic solvents have been analyzed using Kamlet–Taft’s and Swain’s equations. It has been found that the cation-solvating power of the solvents plays a predominant role. It is proposed that the “inactive” tautomer of the phosphorus oxyacids is the reactive species. Transfer of a hydride ion from the P–H bond to PCC, in the rate-determining step, has been proposed.

Computational studies of open-shell phosphorus oxy acids. Pt. 3. Theoretical rotation, pseudorotation, and pseudoinversion barriers for the hydroxyphosphoranyl radical

Computational studies of open-shell phosphorus oxy acids. Pt. 3. Theoretical rotation, pseudorotation, and pseudoinversion barriers for the hydroxyphosphoranyl radical

Computational studies of open-shell phosphorus oxyacids. Cheletropic reaction of PO 2 with H 2

Correlated, spin-unrestricted, electronic structure calculations have been performed for intermediates in the cheletropic reaction of phosphorus dioxide and hydrogen. The reaction involves a change of electronic state and has the high barrier expected for such a symmetry-forbidden, thermal process. The activation energy required by the ground state reactants is between 63 and 82 kcal/mol. However, the reaction of hydrogen with 2Π u PO 2 is predicted to have no barrier.

Hypophosphite transport in human erythrocytes studied by overdetermined one‐dimensional NMR exchange analysis

The membrane transport kinetics of the disubstituted phosphorus oxyacid, hypophosphite, were studied in human red cells under equilibrium exchange conditions. Hypophosphite is an analogue of both the bicarbonate and phosphate ions and is known to be rapidly transported across the human red cell membrane via the anion transport protein, Band 3. The hypophosphite ion is a particularly useful probe of Band 3-mediated membrane transport as the intracellular and extracellular species occur as distinct resonances in the 31P NMR spectrum; as a result the membrane potential may also be readily inferred. We applied 'overdetermined' one-dimensional exchange analysis to estimate the rates of exchange for influx and efflux. The apparent equilibrium exchange (ee) values Kmee for the hypophosphite efflux and influx were different and while the efflux parameters were not able to be unambiguously defined, the measured apparent influx kinetic transport parameters were Vmaxee = 1600 +/- 190 amol cell-1 s-1, and Kmee = 75 +/- 16 mM.

Kinetics and mechanism of the oxidation of phosphinic, phenylphosphinic, and phosphorous acids by pyridinium fluorotrioxochromate(VI)

Oxidation of the lower phosphorus oxyacids by [C5H5NH][CrO3F] results in the formation of corresponding oxyacids in the higher valence states. The reaction is first order with respect to the oxidant concentration. A Michaelis–Menten type kinetics was observed with respect to the substrate, indicating the formation of a complex in a pre-equilibrium. The formation constants and the rates of disproportionation of the complexes have been evaluated at different temperatures. The reaction exhibits a substantial primary kinetic isotope effect. The rates in 19 different organic solvents have been analysed using Kamlet-Taft and Swain equations. It has been found that the cation-solvating power of the solvents plays an important role. It is proposed that the ‘inactive’ tautomer of the phosphorus oxyacids is the reactive reductant, and that transfer of a hydride ion from the P–H bond to the oxidant in the rate-determining step occurs.

The pH dependence of red cell membrane transport of titratable anions studied by NMR spectroscopy.

The effects of varying extracellular pH on the rates of uptake of titratable anions by human erythrocytes under conditions of constant intracellular pH have been determined for a series of highly related anions, the phosphate "analogs." These compounds are simply substituted phosphorus oxyacids, differing in the number and acidity of titratable protons: phosphate (HPO4(2-), pKa 6.8); phosphite (HPO3(2-), pKa 6.4); hypophosphite (H2PO2-); methylphosphonate ((CH3)PO3(2-), pKa 7.4); dimethylphosphinate ((CH3)2PO2-); fluorophosphate [PO3F2-, pKa 4.7); and thiophosphate (HSPO3(2-), pKa 5.5). Suspensions of intact, Cl(-)-loaded erythrocytes (intracellular pH, 7.2) were incubated at 37 degrees C in isotonic buffers (pH 4-8) containing 60 mM phosphate analog for specified time intervals, whereupon influx was halted by the addition of 1 mM 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS), an inhibitor of anion exchange. The intracellular anion concentrations were determined from 31P or 19F nuclear magnetic resonance spectra from the erythrocyte suspensions. The influx rates for the titratable phosphate analogs exhibited bimodal pH dependence, reaching maximal levels at pH values that increased with increasing anion pK. This pH-dependent behavior is consistent with a transport channel that contains a titratable regulatory site which interacts with the translocated anion. Based upon the Henderson-Hasselbalch equation, the probability that a titratable anion will have an electric charge of equal magnitude to that of the titratable carrier is highest at a pH value exactly midway between the pK of the regulatory site and that of the anion. The pH maxima observed for the phosphate analogs indicate a pK for this site of 5.5 at 37 degrees C. Intracellular pH changes associated with influx indicated that transport of the "fast" anion phosphite is largely in monoionized form. Intracellular pH changes associated with transport of slow anions were predominantly determined by partial ionic equilibrium effects and did not indicate the ionization state of the transported anion.

Separation of Some Herbicides by Two Dimensional Thin Layer Chromatography on Calcium Sulphate

Abstract Two dimensional thin layer chromatography is being used for the last forty years1 and now it has became an important tool for the separations of varying complexity. Various coating materials such as alumina, cellulose, kieselgel G, silica gel, silufol and polyamide have been used and studied for the separation of organics such as alkaloids, amino acids, carbohydrates, fatty acids, glycopeptides, glycolipids, lipids, phospholipids, pigments, protiens, peptides, pesticides, steroids and inorganics such as oxy acids of phosphorus, metal ions. Our previous work2′3′4′5′6 shows that calcium sulphate coated paper and glass plates have a great separation potential for herbicides containing carboxyl group. Therefore now an attempt is made to test the separation potential of calcium sulphate alone and calcium sulphate containing aluminium oxide active neutral, calcium carbonate and p-dimethylaminobenzaldehyde for some nerbicides by two dimensional thin layer chromatography. The results obtained are discxis...

ChemInform Abstract: Ab initio Study of the Gaseous Oxyacids of Phosphorus, Their Conjugate Bases, and Their Corresponding Neutral Radicals.

ChemInform Abstract: Ab initio Study of the Gaseous Oxyacids of Phosphorus, Their Conjugate Bases, and Their Corresponding Neutral Radicals.

Ab initio study of the gaseous oxyacids of phosphorus, their conjugate bases, and their corresponding neutral radicals

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAb initio study of the gaseous oxyacids of phosphorus, their conjugate bases, and their corresponding neutral radicalsLawrence L. Lohr and Randall C. BoehmCite this: J. Phys. Chem. 1987, 91, 12, 3203–3207Publication Date (Print):June 1, 1987Publication History Published online1 May 2002Published inissue 1 June 1987https://doi.org/10.1021/j100296a020RIGHTS & PERMISSIONSArticle Views78Altmetric-Citations29LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (641 KB) Get e-Alerts

ChemInform Abstract: Reaction of Phosphorus Oxyacid Esters with p‐Toluenesulfonic Acid.

AbstractBeim Erhitzen von p‐Toluolsulfonsäure (I) mit den Phosphorsäurealkylestern (II) tritt eine Umesterung zu den Sulfonsäureestern (III) ein, deren Ausbeute vom verwendeten Lösungsmittel und dem Molverhältnis zwischen (I) und (II) abhängig ist.

Erythrocyte anion transport of phosphate analogs.

The phosphate analogs are a series of chemically related small anions based upon tetrahedrally bonded phosphorus. Each compound is a mono- or disubstituted phosphorus oxyacid. These chemical substitutions lead to differences in the number and acidity of titratable protons, differences in molecular structures and charge distributions, and unique 31P, 19F, or 1H nuclear magnetic resonance spectra for each analog. These compounds include phosphate, phosphite, hypophosphite, fluorophosphate, thiophosphate, methylphosphonate, and dimethylphosphinate. NMR spectra were obtained from human erythrocytes suspended in buffers containing phosphate analogs. Intracellular and extracellular 31P and 19F chemical shifts of these anions were found to be nonequivalent, due to magnetic susceptibility differences between the two compartments, as well as to the transmembrane pH gradient. NMR spectroscopy was used to measure erythrocyte influx rates of the phosphate analogs, as well as the intracellular and extracellular pH changes that accompany influx, in red cell suspensions incubated for selected time intervals. Anion influx rates were found to vary over three orders of magnitude among the phosphate analogs. All analogs showed concentration-dependent influx rate saturation. The major determinant of influx rates was neither the molecular weight of the analog nor the net charge on the anion, but rather the structure of the anion. Phosphite (HPO2-3), the anion most closely resembling bicarbonate (a natural substrate for anion exchange) was found to have the highest influx rate.

Reaction of phosphorus oxyacid esters with p-toluenesulfonic acid.

The reaction of primary alkyl esters of phosphorus oxyacids with p-toluenesulfonic acid (TsOH) in refluxing solvents gave the correspondinf p-toluenesulfonates (TsOR). We found that the secondary alkyl esters reacted with TsOH at lower temperature (r.t.-40°C) to afford TsORs in good yields. It is suggested that sulfonic acids may be useful for the selective dealkylation of mixed esters.

Ammonia chemical ionization mass spectra of esters and amides of oxyacids of phosphorus

AbstractChemical ionization mass spectrometry using ammonia as the reagent gas has been carried out with esters and amides of a variety of oxyacids of phosphorus (phosphates, phosphonates, phosphites and phosphoramidates). In all cases, the protonated molecular ion is a major species in the spectrum and the percentage of the total ion current carried by these protonated molecular ions is always considerably greater than that carried by the molecular ions in the corresponding electron impact mass spectra. In the chemical ionization mass spectra only limited fragmentation of the protonated molecular ion occurs from which useful information on the structure of phosphorus derivatives may be inferred.