Formation Of Sodium Research Articles

Synthesis of (Indenylidene)phosphoranes − A Novel Class of Ligand Precursors for Main‐Group and Transition Metal Organometallics

AbstractIndPPh2 (1) reacts with RCH2Br to form the phosphonium salts [RCH2P(Ph)2Ind]+Br− (2: R = Ph; 3: R = C6F5) in high yields. Oxidation of 1 with H2O2 in THF proceeds smoothly to give the phosphane oxide IndP(O)Ph2 (4). Dehydrobromination of 2 and 3 with NaH in THF yields the corresponding indenylidenephosphoranes C9H6=P(Ph)2CH2R (5: R = Ph; 6: R = C6F5). Further deprotonation of 6 with excess NaH results in formation of sodium 1‐{[(pentafluorophenyl)methylidene]diphenylphosphoranyl}indenide (7), isolated as a solvate with three THF molecules. A detailed NMR study of new ligand precursors and X‐ray structure studies of 5 and 7 have been accomplished. A short F→Na coordination contact in the molecular structure of 7 has been detected. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Synthesis of the monosubstituted arylcyanoxime and its Na, Tl(I) and Ag(I) compounds

Nitrosation of 2-chlorophenyl acetonitrile with t-butylnitrite under basic conditions (Meyer reaction) resulted in a high-yield preparation of the first substituted arylcyanoxime, 2-chlorophenyl(oximino)acetonitrile, H(2Cl–PhCO) (HL). The obtained cyanoxime is readily deprotonated in solution by metal hydroxides or carbonates with the formation of yellow sodium, tetrabutylammonium, thallium(I) and silver(I) derivatives. The crystal structure of the Tl(I) complex was determined. Thallium(I) salt (TlL) crystallizes in the monoclinic space group P21 n with a = 3.8382(7), b = 11.0065(18), c = 20.901(4) Å, and β = 92.447(3)°, V = 882.2(3) Å3, Z = 4; T = 193 K (Mo Kα radiation). The structure was solved by direct methods to a final R of 0.0689 (wR2 = 0.1650) for I > 2σ(I). The crystal structure of the complex is a one-dimensional coordination polymer that consists of centrosymmetric [TlL]2 dimers in which Tl2O2 rhombohedra are connected to each other at 90.72°. The crystal structure of TlL is an interesting example of the ruffled metal-organic network composed of Tl–O–Tl–O zigzag chains with close (3.838 Å) intermetallic distances comparable to those in metallic thallium (3.42 Å). The cyanoxime anion bridges metal centers and acts as a tridentate ligand where oxygen atoms of the oxime group bond to three different Tl(I) cations with three different bond lengths.

Rheological properties of sodium caprate‐induced β‐lactoglobulin gel and changes in secondary structure during gelation

AbstractIn this study, we found that transparent gels of β‐lactoglobulin (β‐LG) were formed by adding different concentrations of sodium caprate to protein solutions at ambient temperature. We investigated changes in the dynamic viscoelasticity of the mixture with time at 25°C and found that more than 12% β‐LG induced the formation of a viscoelastic gel with a suitable amount of sodium caprate (for example, 12% β‐LG and 3.6% sodium caprate). Furthermore, we analyzed the changes in the secondary structure of proteins during the gelation step by FHR spectroscopy. Dissociation of the β‐LG dimer was first observed just after mixing with sodium caprate. Furthermore, in the β‐LG protein in which the original contents were predominantly β‐sheets, intermolecular β‐sheets attributable to aggregation increased with a decrease in the content of intramolecular β‐sheets. Sodium caprate‐induced gel was heated at 80°C for 30 min after the gel was formed, and a large increase in the intermolecular β‐sheet bands was observed by heat treatment. These results suggest that the formation of sodium caprate‐induced gels of β‐LG was accompanied by less marked changes in the protein conformation than those in heat‐induced gels.

Spatiotemporal Dynamics of Vapors of Chloride Matrices in a Transversely Heated Graphite Furnace for Atomic Absorption Spectrometry

The dynamic of the formation and dissipation of sodium and nickel chloride vapors in the THGA transversely heated graphite furnace atomizer of a SIMAA 6000 multielement spectrometer was investigated by shadow spectral filming. The spatial distribution for the entire vaporization cycle of vapors is strongly inhomogeneous, due mainly to the transverse non-isothermal conditions of the atomizer. It also depends on the addition of a chemical modifier and the rate of the internal flow of the sheath gas. At the normal brightness of the spectral lamps, the spectrometer's Zeeman-based background corrector reliably compensates for the nonselective light absorption by molecular vapors and condensed particles with an amplitude of up to 1. For the minimum allowable brightness of lamps, this value decreases to as low as 0.6 because of an increase in the noise of the measurement path.

Functional Polymer Colloids with Ordered Interior

Polymer colloids with internal ordering were synthesized using hydrolytic condensation of octadecyl-dimethyl(3-trimethoxysilylpropyl)ammonium chloride (ODMACl) and a mixture of ODMACl and the trisodium salt of the triacetic acid N-(trimethoxysilylpropyl)ethylenediamine (TANED). The structure and morphology of these colloids were studied with small-angle X-ray scattering, transmission electron microscopy, nuclear magnetic resonance, sedimentation in ultracentrifuge; and other methods. When polymer colloids are obtained from a single precursor (ODMACl), their local structure, molecular weight characteristics, and morphology strongly depend on the reaction conditions, while lamellar ordering remains nearly unaffected. Use of a mixture of cationic and anionic silanes (ODMACl and TANED) as precursors in hydrolytic condensation results in novel zwitterionic copolymer colloids with two-dimensional hexagonal packing. Interaction of the ODMACl quaternary ammonium groups with the three carboxy groups of TANED leads to replacement of sodium and chloride ions and formation of gegenions, resulting in a molar ratio ODMACl:TANED = 3:1 (each TANED molecule contains three carboxy groups). Due to their ordered interior, polyODMACl (PODMACl) and PODMACl-TANED colloids can be used as templates for controlled positioning of nanoparticles within these colloids. For example, lamellar ordering controls Pt nanoparticle formation within PODMACl colloids providing Pt nanoparticle alignment within the lamellar structure. Loading of PODMACl-TANED colloids with iron salts followed by pH increase results in the formation of iron oxide nanoparticles located within PODMACl-TANED cylinders.

Sensitive liquid chromatographic/tandem mass spectrometric method for the determination of beclomethasone dipropionate and its metabolites in equine plasma and urine.

Beclomethasone dipropionate (BDP) is a potent pro-drug to beclomethasone (BOH) and is used in the treatment of chronic and acute respiratory disorders in the horse. The therapeutic dose of BDP (325 microg per horse) by inhalation results in very low plasma and urinary concentrations of BDP and its metabolites that pose a challenge to detection and confirmation by equine forensic laboratories. To solve this problem, a method involving the use of a liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) was developed for the detection, confirmation and quantification of the analytes in equine samples. Ammonium formate or acetate buffer added to LC mobile phase favored the formation of [M + H](+) ions from BDP and its metabolites, whereas formic acid led to the formation of sodium and potassium adduct ions ([M + Na](+), [M + K](+)) together with [M + H](+) ions. Acetonitrile, on the other hand, favored the formation of abundant solvent adduct ions [M + H + CH(3)CN](+) with the analytes under electrospray ionization (ESI) and atmospheric pressure chemical ionization conditions. In contrast, methanol formed much less solvent adduct ions than acetonitrile. The solvent adduct ions were thermally stable and could not be completely desolvated under the experimental conditions, but they were very fragile to collision-induced dissociation (CID). Interestingly, these solvent adduct ions were observed on a triple-quadrupole mass spectrometry but not on an ion trap instrument where helium used as a damping gas in the ion trap might cause the solvent adduct ions desolvated by collision. By CID studies on the [M + H](+) ions of BDP and its metabolites, their fragmentation paths were proposed. In equine plasma at ambient temperature over 2 h, BDP and B21P were hydrolyzed in part to B17P and BOH, respectively, but B17P was not hydrolyzed. Sodium fluoride added to equine plasma inhibited the hydrolysis of BDP and B21P. The matrix effect in ESI was evaluated in equine plasma and urine samples. The method involved the extraction of BDP and its metabolites from equine plasma and urine samples by methyl tert-butyl ether, resolution on a C(8) column with a mobile phase gradient consisting of methanol and ammonium formate (2 mmol l(-1), pH 3.4) and multiple reaction monitoring for the analytes on a triple-quadrupole mass spectrometer. The detection limit was 13 pg ml(-1) for BDP and B17P, 25 pg ml(-1) for BOH and 50 pg ml(-1) for B21P in plasma and 25 pg ml(-1) for BOH in urine. The method was successfully applied to the analysis of equine plasma and urine samples for the analytes following administration of BDP to horses by inhalation. B17P, the major and active metabolite of BDP, was detected and quantified in equine plasma up to 4 h post-administration by inhalation of a very low therapeutic dose (325 microg per horse) of BDP.

Thermodynamics of formation of ammonium, sodium and potassium alums and chromium alums

The Pitzer ion-interaction model has been used for thermodynamic simulation of the binary Cr 2(SO4) 3H2O, KCr(SO4) 2H2O, and ternary (NH 4) 2SO 4Al 2(SO 4) 3H 2O, Na 2SO 4Al 2(SO 4) 3H 2O, K 2SO 4Al 2(SO 4) 3H 2O, (NH 4) 2SO 4Cr 2(SO 4) 3H 2O, Na 2SO 4Cr 2(SO 4) 3H 2O, and K 2SO 4Cr 2(SO 4) 3H 2O systems at T=298.15 K. The optimum values of the binary parameters of ionic interactions for chromium solutions have been calculated using osmotic data for unsaturated binary solutions. The mixing parameters have been chosen on the basis of the compositions of saturated ternary solutions and data on the binary solubility of the alums and chromium alums in water. Good agreement between experimentally determined and calculated solubilities has been found. Important thermodynamic characteristics (thermodynamic solubility product, standard molar Gibbs energy of formation) of the solid phases (simple and double salts) crystallizing in the systems under consideration are determined.

The gas-phase sodium basicities of common matrix-assisted laser desorption/ionization matrices

The gas-phase sodium basicities (GNaB) of common matrix-assisted laser desorption/ionization (MALDI) matrices were determined in a Fourier transform ion cyclotron resonance mass spectrometer (FT ICR MS) by monitoring the sodium ion transfer reaction between sodiated matrix molecules and a reference base with known gas-phase sodium basicity. The data was analyzed by two methods: one where the equilibrium constant was determined directly from ion concentrations at equilibrium and the other based on fitting the reaction kinetics over the full reaction time scale. Fitting of the reaction kinetics solved the problem of competing reactions, i.e. formation of sodium bound dimers, which complicates direct determination of the equilibrium constant. The gas-phase sodium ion basicities of twelve MALDI matrices were found to lie between 140–170 kJ mol −1. The activation energy of the rate-limiting step was also determined.

The alkali–silica reaction in alkali-activated granulated slag mortars with reactive aggregate

The expansion of alkali-activated granulated blast furnace slag (AAS) cement mortars with reactive aggregate due to alkali–silica reaction (ASR) was investigated. The alkaline activator used was NaOH solution with 4% Na 2O (by mass of slag). These results were compared to those of ordinary portland cement (OPC) mortars. The ASTM C1260-94 Standard Test Method based on the NBRI Accelerated Test Method was followed. The nature of the ASR products was also studied by SEM/EDX. The results obtained show that the AAS cement mortars experienced expansion due to the ASR, but expansion occurs at slower rate than with OPC mortars under similar conditions. The cause of the expansion in AAS cement mortars is the formation of sodium and calcium silicate hydrate reaction products with rosette-type morphology. Finally, in order to determine potential expansion due to ASR, the Accelerated Test Method is not suitable for AAS mortars because the reaction rate is initially slow and a longer period of testing is required.

Porous poly(D,L-lactide) and poly(D,L-lactide-co-glycolide) produced by thermal salt elimination from halogenocarboxylatesElectronic supplementary information (ESI) available: detailed results of the combustion calorimetric experiments. See http://www.rsc.org/suppdata/dt/b1/b104979h/

Poly(D,L-lactide) has been obtained by thermal elimination of alkali chloride from alkali 2-chloropropionates. Preparative studies and differential scanning calorimetry (DSC) have shown that while the sodium and potassium compounds undergo a clean polymerisation, the lithium analogues decompose on heating without polymerisation. The energetics of the polymerisation reaction have also been investigated by determining the enthalpies of formation of sodium and lithium (S)-2-chloropropionates (from reaction-solution calorimetry), and the enthalpies of formation of poly(L-lactide) and poly(D,L-lactide) (from micro combustion calorimetry). The results suggest that the polymerisation process is thermodynamically favourable for the sodium compounds but not for the lithium compounds, in good agreement with the experimental observations. Copolyesters of glycolic acid (polyglycolide) and lactic acid (polylactide) have been prepared by thermal reaction of crystal mixtures of sodium or potassium chloroacetates and sodium or potassium 2-chloropropionates, which were obtained by co-precipitation of the precursor compounds from methanol solutions. The crystal mixtures and reaction products have been characterised by a number of techniques, including solid state NMR spectroscopy and X-ray powder diffraction. For high contents of glycolide, the reaction occurred entirely in the solid state, whereas for cases with more than 10 mol% lactide, a melt is formed which solidifies on cooling to room temperature. The products are lactide-terminated block copolymers with typical chain lengths of 40 monomer units. Due to the solvent-free nature of the synthesis, all polymers can be obtained with microporous morphology.

Complexes of heteroscorpionate trispyrazolylborate anionic ligands. Part III. X-ray crystallographic and NMR studies on cobalt(II) complexes with tris(pyrazolyl)borate anionic ligands obtained from 3,5-di-methylpyrazole and 3(5)-methyl,5(3)-phenylpyrazole

Condensation of 2 equiv. of 5(3)-methyl,3(5)-phenylpyrazole and 1 equiv. of 3,5-di-methylpyrazole with NaBH 4 resulted in the formation of sodium [hydrobis(3-phenyl,5-methylpyrazolyl)(3,5-di-methylpyrazolyl)borate]. The ligand was converted into the pentacoordinate [HB(3,5-di-Mepz)(3-Ph,5-Mepz) 2]Co(NCS)(THF)·THF complex for which the molecular structure was determined by the X-ray crystallographic method. The geometry of the ligand in the cobalt(II) complex was compared with that of the homoscorpionate ligand in [HB(3-Ph,5-Mepz) 3]Co(NCS)(THF)·0.5THF on the basis of X-ray structural data. The condition for the thermal conversion of the ligands in the studied Tp′Co(NCS) was established. The heating of the mentioned complexes at 428 K in propylbenzene resulted in a borotropic shift of 3-phenyl,5-methylpyrazolyl moieties resulting in the formation of new heteroscorpionates: the chiral [HB(3,5-di-Mepz)(3-Ph,5-Mepz)(3-Me,5-Phpz)]Co(NCS) and [HB(3-Me,5-Phpz) 2(3-Ph,5-Mepz)]Co(NCS), which were characterized in solution by 1H NMR spectroscopy.

Homo- and heterocomplexes of sodium and lithium amides--structures in solution.

Addition of the chiral amine (S)-methyl(1-phenyl-2-pyrrolidinoethyl)[15N]amine (1) to a large excess of nBuNa resulted in the formation of a mixed sodium amide/nBuNa complex. This is the first observation of such a complex. Addition of nBuLi to the chiral sodium amide dimer 3 gave a new mixed lithium/sodium amide 5. The use of 15N,6Li coupling constants showed that the lithium in 5 occupied the tetracoordinated site. The use of chiral sodium amide 3 in the desymmetrization of cyclohexene oxide gave a modest enantiomeric excess (ee) of 37%. The corresponding lithium amide gave an ee of 70% of the same enantiomer. This is the first example of the comparison of asymmetric induction by sodium as cation with that of lithium.

Standard Enthalpies of Formation of Li, Na, K and Tl Cyclopentadienyls

The enthalpies of formation of lithium, sodium, potassium and thallium cyclopentadienyls were determined by reaction-solution calorimetry as ΔfH° [LiCp] = −76.5 ± 2.9 kJ/mol, ΔfH° [NaCp] = −39.7 ± 2.5 kJ/mol, ΔfH° [KCp] = −83.2 ± 3.2 kJ/mol, and ΔfH° [TlCp] = +117.7 ± 1.9 kJ/mol. Using a previously developed model, the enthalpies of formation of RbCp and CsCp were estimated.

Standard Enthalpies of Formation of Li, Na, K and Tl Cyclopentadienyls

The enthalpies of formation of lithium, sodium, potassium and thallium cyclopentadienyls were determined by reaction-solution calorimetry as ΔfH° [LiCp] = −76.5 ± 2.9 kJ/mol, ΔfH° [NaCp] = −39.7 ± 2.5 kJ/mol, ΔfH° [KCp] = −83.2 ± 3.2 kJ/mol, and ΔfH° [TlCp] = +117.7 ± 1.9 kJ/mol. Using a previously developed model, the enthalpies of formation of RbCp and CsCp were estimated.

Synthesis and Examination of Electrolytic Sodium–Vanadium Oxide Compounds Intended for Cathodes of Lithium Batteries: The Mechanism of Formation of Electrolytic Bronze β-NaxV2O5

To determine the mechanism responsible for the formation of electrolytic sodium–vanadium oxide bronze e-Na x V2O5, synthesized earlier from acid vanadyl sulfate electrolyte, β-bronze i-Na x V2O5is synthesized by exposing electrolytic oxide e-V2O5in the same sodium-containing electrolyte under open-circuit conditions, with a subsequent annealing of the sample. It is established that the two modifications of β-bronze (e-Na x V2O5and i-Na x V2O5) are identical and that electrolytic precursors of β-bronze Na x V2O5form via an ion-exchange mechanism.

Mécanismes moléculaires du syndrome néphrotique idiopathique

Steroid-sensitive idiopathic nephrotic syndrome is a T-cell disorder associated with a functional renal impairment. The molecular mechanisms leading from the stimulation of the immune system to the clinical expression of the renal disease can be analyzed according to five biological events: 1) a Th2 activation of T-cells by interleukin-13; 2) a yet unidentified glomerular permeability factor from immune origin; 3) a molecular disorientation of slit diaphragms or glomerular basement membrane responsible for proteinuria; 4) a podocyte cytoskeleton rearrangement responsible for foot process effacement; and 5) renal avidity for sodium and edema formation resulting from a primary stimulation of tubular Na,K-ATPase and an increase of endothelial permeability.

No Lurking Inconsistency

Daly (1999) claims there is a deep inconsistency in viewing as a purposeless process while acknowledging that exists in the natural world. He sees this inconsistency as a threat to scientific arguments for conservation biology and as grounds for disqualifying Neo-Darwinist biologists and ecologists from contributing to discussions concerning conservation. We believe these claims to be unfounded. Authors must be precise about the use of words such as purpose. Wh-en scientists say that, prior to the dawn of life, the universe was without purpose, they mean there is no evidence of a plan or intentional force that shaped development of the physical universe. For example, it makes no sense to ask is the of sodium? or What is the of planets? Through these questions we are asking about a prior intent that led to the formation of sodium or planets, and there is no evidence of any such force or plan. All evidence indicates that life arose from this purposeless and lifeless universe by purely mechanical processes; life did not arise for a purpose. Once life arose on Earth and began to exhibit genetic variation, different life forms experienced differential survival and reproductive success within certain environmental (abiotic and biotic) conditions. That is, natural selection began to shape life forms as a consequence of how they matched certain environmental opportunities and constraints. As a result, organisms show what Simpson (1964) called apparent purposefulness. Organisms have structures and functions that seem to serve a purpose-eyes for perceiving objects, hearts for pumping blood, and shells for protection. On another level, animals that have not eaten for some time are stimulated to begin foraging or hunting, and it is not inappropriate to say that they are searching for food; hunting is for a purpose. But hunting is like all adaptations, a feature of an organism that has contributed to its survival and reproduction in specific environments; such features arose as a consequence of purposeless mutations and were selected by a purely mechanistic process unguided by an a priori purpose. The development of human-level neural capacity came about through natural selection but gave humans capabilities that were almost certainly not selected for. At least some of our capacity for inorganic or evolution -the ability to discover and pass on ideas, technologies, and behaviours without a change in our genetic makeup-is one of these abilities. Humans have been able to use their cognitive power to frame purposes -to do things for reasons or to act with free willin ways other animals have not. Thus, a process (evolution) that is completely purposeless and completely mechanistic has led to a life form that is capable of generating purpose cognitively. Referring to cultural as the new evolution, Simpson (1967: 293) explained:

Hydrothermal Synthesis of Sodium and Potassium Bismuth Titanates

A thermodynamic model of electrolyte solutions has been used as a tool for equilibrium calculations in the Na−Bi−Ti−H2O and K−Bi−Ti−H2O systems. To perform the calculations, unknown standard-state properties for Na0.5Bi0.5TiO3 (NBT), K0.5Bi0.5TiO3 (KBT) and other solid compounds that exist in these systems were established. As a result of the calculations, stability and yield diagrams of the investigated systems were computed. Thus, the optimum conditions (i.e., temperature, synthesis precursor concentrations, solution pH) for the hydrothermal synthesis of phase-pure KBT and NBT are presented in a graphical form. They show the concentrations of precursors and pH-adjusting agents required for the formation of phase-pure alkaline bismuth titanates. The computed diagrams show that the formation of phase-pure sodium and potassium bismuth titanates takes place in highly alkaline solutions (e.g., at pH above 11.4 and 12.2, respectively, at 473 K). Results of our experiments validated the newly developed yield diagrams and demonstrated, for the first time, that alkaline bismuth titanates can be hydrothermally synthesized. Experimental synthesis was carried out using both conventional and microwave-heated reactors.

Complexation and ionophoric properties of taxol and colchicine: complex formation and transport of sodium, potassium, magnesium and calcium ions across a liquid membrane

We report the activities of taxol (an anticancer drug) and colchicine, which are inhibitors of microtubule organization, on the complexation and transport of Na+, K+, Mg2+ and Ca2+ ions across a liquid membrane, using a spectrophotometric procedure. Taxol, a diterpenoid compound, that has been demonstrated to possess a potent antitumour activity, is shown to extract Na+, K+, Mg2+ and Ca2+ ions from the aqueous solution to the organic phase with preference for Ca2+ ions. A kinetic study of the transport and complexation of Na+, K+, Mg2+ and Ca2+ ions through a liquid membrane revealed that the K+ ion is more rapidly transported and the Ca2+ ion is more rapidly complexed than other ions. However, colchicine, another alkaloid compound, extracted and transported only the divalent ions tested, Mg2+ and Ca2+. In both complexation and transport, the flux of the ions increases with the concentration of taxol or colchicine. Complexation and ionophoric properties of taxol and colchicine sheds new lights on therapeutic properties of these drugs. The treatment of disease states by the administration of these drugs to alter membrane permeability will prove to be a valuable therapeutic concept.

Complexation and ionophoric properties of taxol and colchicine: complex formation and transport of sodium, potassium, magnesium and calcium ions across a liquid membrane.

We report the activities of taxol (an anticancer drug) and colchicine, which are inhibitors of microtubule organization, on the complexation and transport of Na+, K+, Mg2+ and Ca2+ ions across a liquid membrane, using a spectrophotometric procedure. Taxol, a diterpenoid compound, that has been demonstrated to possess a potent antitumour activity, is shown to extract Na+, K+, Mg2+ and Ca2+ ions from the aqueous solution to the organic phase with preference for Ca2+ ions. A kinetic study of the transport and complexation of Na+, K+, Mg2+ and Ca2+ ions through a liquid membrane revealed that the K+ ion is more rapidly transported and the Ca2+ ion is more rapidly complexed than other ions. However, colchicine, another alkaloid compound, extracted and transported only the divalent ions tested, Mg2+ and Ca2+. In both complexation and transport, the flux of the ions increases with the concentration of taxol or colchicine. Complexation and ionophoric properties of taxol and colchicine sheds new lights on therapeutic properties of these drugs. The treatment of disease states by the administration of these drugs to alter membrane permeability will prove to be a valuable therapeutic concept.