bluuebunny/crossref_metadata_2025 huggingface dataset:
Nuclear recoil reactions in polynuclear metal carbonyls
Authors: Narayan S. R. , Wiles D. R.
Published: May 2006

Nuclear recoil reactions have been studied in the compounds Ru3(CO)12, Fe3(CO)12, Fe(CO)5, and W(CO)6, with the objective of testing the hypothesis that the retention would be closely related to the molecular complexity. Retention values were found to be 41, 26, 41, and 52%, respectively, after exhaustive purification, and the hypothesis is concluded to be invalid for these compounds. A recoil yield of 26% is found for Fe3(CO)12 in Fe(CO)5, and 17% for Fe(CO)5 in Fe3(CO)12. Some reactions are suggested which can account qualitatively for the observed results. The critical stage of the reaction is assumed to be the hot-zone formation of a mononuclear radioactive species M(CO)3 or M(CO)4, which reacts further by various stepwise reactions.A retention of 52 or 64% was found for W(CO)6, depending on whether column chromatography or vacuum sublimation was used as the first step in the separation. The lower value is preferred.
Phosphinohydrazines. Part II. Reactions of N,N-dimethylhydrazine and trimethylhydrazine with substituted phosphines
Authors: Peterson L. K. , Wilson G. L. , Thé K. I.
Published: May 2006

Reactions between trimethylhydrazine and (CF3)2PI, and between N,N-dimethylhydrazine and CF3PI2 have been utilized as synthetic routes to phosphinohydrazine compounds. Two new compounds, trimethylhydrazino-bis(trifluoromethyl) phosphine (m.p. −47.00°, b.p. 130.5° extrapolated) and bis-(N,N-dimethylhydrazino)-trifluoromethylphosphine (m.p. 49.20°, b.p. 184° extrapolated), are described.
Nuclear magnetic resonance spectra of ortho-, meta-, and para-difluorobenzenes in a nematic liquid crystal solvent
Authors: Yim C. T. , Gilson D. F. R.
Published: May 2006

The proton and fluorine magnetic resonance spectra of ortho-, meta-, and para-difluorobenzene dissolved in a nematic liquid crystal solvent have been analyzed. Expressions for the anisotropy of the fluorine chemical shift were obtained but an attempt to fit these to the Karplus and Das theory failed. Hydrogen atoms ortho to fluorine show small displacements from their expected positions.
Studies in terpenoids. XII. Optical rotatory dispersion and circular dichroism studies on some cyclobutanones derived from α-pinene
Authors: Subramanian L. R. , Rao G. S. Krishna
Published: May 2006

The optical rotatory dispersion and circular dichroism studies on the cyclobutanones (1–5) are discussed.
Free radicals by mass spectrometry. XL. Primary processes and transient intermediates in the mercury (3P1) photosensitization of hydrazine
Authors: Jones A. , Lossing F. P.
Published: May 2006

The low pressure mercury (3P1) photosensitized decomposition of hydrazine has been studied at 55 °C in a fast flow reactor coupled to a mass spectrometer. Direct evidence was obtained for the participation of N2H2, N2H3, NH2, and NH in the decomposition, and two primary decomposition modes were established[Formula: see text]
Dehydrochlorination of chlorodihydridocarbonylbis(triphenylphosphine)Ir(III) in the presence of strong bases
Authors: Harrod J. F. , Gilson D. F. R. , Charles R.
Published: May 2006

The dehydrochlorination of dihydridochlorocarbonylbis(triphenylphosphine)iridium(III) by organic and inorganic bases is described. The manner in which this reaction provides a formal link between the homolytic activation of hydrogen at a single metal center and the heterolytic activation of hydrogen is discussed.
Structure of the product obtained in the base-catalyzed condensation of acetone and indanedione-1,3
Authors: Kuhn Stephen J.
Published: May 2006

It has been found that acetone and indanedione-1,3 gives 1,1-dimethyl-3-oxo-1,2,3,9a-tetrahydro-9-indanedionylene fluorene in the presence of a base, instead of 1,1-dimethyl-3-oxo-1,2,3,4-tetrahydro-9-indanedionylene fluorene or other products claimed in the literature. The nuclear magnetic resonance spectra of the product and some of its derivatives have been recorded.
Synthesis of epimeric 2-acetamido-2-deoxyheptoses from D-mannose, D-galactose, and D-talose
Authors: Gibbs C. F. , Williams D. T. , Perry M. B.
Published: May 2006

D-Mannose, D-galactose, and D-talose were converted via the action of nitromethane to their corresponding 3,4,5,6,7-pentaacetoxy-1-nitro-1-heptene derivatives which on treatment with ammonia afforded theepimeric2-acetamido-1,2-dideoxy-1-nitroheptitol derivatives. The 2-acetamido-1,2-dideoxy-1-nitroheptitols were converted via the Nef reaction to the corresponding 2-acetamido-2-deoxyheptoses. The configuration of the 2-acetamido-2-deoxyheptoses was established by their degradation to known 2-acetamido-2-deoxyhexitol derivatives. The properties of the 2-acetamido-2-deoxyheptoses are described.
Reactions of hydrazines with phosphate esters
Authors: Vis Jan H. , Meinke Phyllis
Published: May 2006

Phosphate esters with the general formula (RO)2P(O)OR′, with R = methyl or phenyl, and R′ = H, methyl, or phenyl, but with a maximum of two phenyls per molecule, react with hydrazines to form hydrazinium phosphates. Continued substitution of hydrazine protons by methyl groups appears to be a combination of methylation by phosphate esters and proton abstraction by part of the hydrazine present.
Comments and Summary
Authors: Phelps A. V.
Published: May 2006

not available
Neutral reactions involving oxygen and nitrogen
Authors: Schiff H. I.
Published: May 2006

Methods of production and detection of reactive species of oxygen and nitrogen are discussed briefly. Kinetic data for reactions of these species which have aeronomic interest are reviewed. New data, obtained during the past 4 years are critically compared, and recommendations made for "best" values where possible. An attempt is also made to delineate important areas where additional work is needed to meet the demands of atmospheric modelling.
Kinetics and mechanism of the addition of dimethylarsine to hexafluorobutyne-2
Authors: Cullen W. R. , Leeder W. R.
Published: May 2006

The addition of dimethylarsine to hexafluorobutyne-2 follows second order kinetics with activation energy, 6.09 ± 0.20 kcal/mole, and activation entropy, −48 ± 1 e.u. The product distribution of the competitive reaction of dimethylarsenic deuteride and diethylarsine with the acetylene shows that the addition mainly involves an intermolecular proton transfer. The mechanism of the addition is discussed.
An analytical method of calculating thermodynamic data in ternary systems
Authors: Pelton A. D. , Flengas S. N.
Published: May 2006

Relationships between the coefficients of series expansions in the composition variables for isothermal partial molar properties of all components, and for the corresponding integral property in a ternary system, have been developed. These relationships allow the calculation of the isothermal partial properties of mixing of all components, from experimental values of this property for one component, or from experimental measurements of the corresponding integral property of mixing. The form of the series expansions is such as to permit the easy fitting of the experimental data by standard least-squares techniques. Experimental data in a binary sub-system or experimentally determined phase boundary positions may easily be used to give end-points for the calculation. The method is faster and more accurate than the older graphical integration techniques. The simplicity of the method depends upon the proper choice of composition variables. Sample calculations have been done for the Cd–Bi–Sn system, using computer programs designed for the purpose.
Infrared spectra of adducts of tetrasulfur tetranitride with metal halides
Authors: Ashley P. J. , Torrible E. G.
Published: May 2006

New complexes of S4N4 with TiBr4, ZrCl4, NbCl5, and TaCl5 have been prepared. The infrared spectra of these complexes together with the spectra of previously reported complexes have been determined. Possible structures for the complexes are discussed.
Organic compounds of gallium. III. Reactions of gallium alkoxides with acetylacetone, ethyl acetoacetate, methyl acetoacetate, and methyl salicylate
Authors: Mehrotra R. C. , Bindal S. R.
Published: May 2006

Derivatives of gallium of the type: Ga(i-C3H7O)3−xligx (x = 1, 2, or 3; and H lig = acetylacetone, methyl and ethyl acetoacetate, or methyl salicylate) have been synthesized by reacting gallium alkoxides with ligands in various molar ratios. The compounds are soluble in organic solvents and could be volatilized under reduced pressure. Their molecular weights have been determined ebullioscopically. The infrared spectra of some of the compounds have been studied.
Oxidation of formaldehyde by copper(II) in aqueous solution
Authors: Byerley J. J. , Teo W. K.
Published: May 2006

Copper(II) was found to oxidize formaldehyde in aqueous solutions according to the following reaction[Formula: see text]Rates were determined at temperatures between 130 and 166.5 °C. The rate law was found to be of the form[Formula: see text]where k1 = 1.9 × 10−4 M−1 s−1 and k2 = 2.05 × 10−8 s−1 in 0.125 M acetate solutions at 160 °C. The apparent activation energy is 33 600 cal/mole. The reaction mechanism suggested includes the formation of two bridged intermediates[Formula: see text]which account for the acid-dependent and acid-independent reaction paths.
Sur quelques réactions acide-base dans les solvants fortement basiques anhydres. II. Les amino-2 éthylamidures de sodium et de potassium
Authors: Heumann W. R. , Bouchard A. , Šafařík L.
Published: May 2006

Solutions of sodium 2-aminoethylamide in anhydrous ethylenediamine were prepared by dissolving ammoniacal sodium amide NaNH2 in ethylenediamine and removing the ammonia formed in vacuum. When these solutions were prepared and kept under nitrogen containing not more than about 5 p.p.m. of oxygen and 1 p.p.m. of moisture, they remained colorless and stable. Upon addition of benzene to these solutions, the pure amide precipitated as fine greyish–white crystals, which were also stable under pure nitrogen. The potassium 2-aminoethylamide was prepared in a similar way from ethylenediamine and potassium hydride. Its solid product resembles that of the corresponding sodium amide, but its solutions in ethylenediamine are less stable, rapidly turning dark brown because of polymerization. The basic strengths of these two 2-aminoethylamides were compared with the corresponding lithium amide by following potentiometrically the neutralization of ethylenediamine solutions of hydrochloric acid, p-methoxyphenol, water, and ethanolamine respectively. According to the heights of the potential jumps at the equivalence points the basic strength of the amides was found to increase in the order Na < Li < K.
Structure of sibiricine, an alkaloid of Corydalissibirica
Authors: Manske R. H. F. , Rodrigo R. , MacLean D. B. , Gracey D. E. F. , Saunders J. K.
Published: May 2006

Structure 1 is proposed for sibiricine, a minor alkaloid of C. sibirica. The structural assignment rests on an interpretation of its mass spectrum and its proton magnetic resonance (p.m.r.) spectrum.
Reactions of organotin compounds. X. Reactions of tin hydrides with CF2=CFRe(CO)5, CF3CF=CFRe(CO)5, and some fluorinated alkenes
Authors: Akhtar M. , Clark H. C.
Published: May 2006

Trimethyltin hydride reacts with CF2=CFRe(CO)5 under ultraviolet irradiation to give new fluorovinyl derivatives of —Re(CO)5. Similar products were obtained using dimethyltin dihydride, but no reaction occurred between trimethyltin hydride and CF3CF=CFRe(CO)5. The reactions of trifluoroethylene, 1,1-difluoroethylene, and vinyl fluoride with trimethyltin hydride have been studied, thus completing the sequence of such reactions with fluorinated ethylenes. While both possible addition products were obtained with trifluoroethylene, and also from the corresponding reaction with perfluoropropene, 1,1-difluoroethylene gave only (CH3)3SnCH2CF2H, and with vinyl fluoride only trimethyltin fluoride and ethylene were isolated. Possible explanations are proposed and spectroscopic data for the new compounds are presented.
Oxidation with lead tetraacetate. IV. Cyclization of phenylhydrazones of levulinic acid, levulinanilide, 5-ketohexanoic acid, 4-keto-1-pentanol, and of levulinic acid oxime
Authors: Gubelt Gertfried B. , Warkentin John
Published: May 2006

The phenylhydrazones of levulinic acid (3a) and 5-ketohexanoic acid (4) are cyclized by lead tetraacetate (LTA) to γ-phenylazo-γ-valerolactone (9a) and δ-phenylazo-δ-caprolactone (11), respectively. Oxidation of levulinanilide phenylhydrazone (3b) leads, by analogous oxygen-to-carbon ring closure, to γ-phenylazo-α-phenylimino-γ-valerolactone (15) which is hydrolyzed to 9a. Similarly, the phenylhydrazone of 4-keto-1-pentanol (5) is cyclized to 2-phenylazo-2-methyl tetrahydrofuran (12) and the oxime of levulinic acid (7) is converted to γ-nitroso-γ-valerolactone which is isolated as the dimer, trans-bis[γ-nitroso-γ-valerolactone] (14).
Ionization of liquid argon by X-rays: -value
Authors: Klassen N. V. , Schmidt Werner F.
Published: May 2006

Liquid argon at 87 °K was irradiated with 1.5 MeV X-rays. Saturation currents were achieved at low dose rates. The energy required to produce an ion pair [Formula: see text] was found to be 22.5 ± 3 eV, which is similar to the gas phase value.
Synthèse et propriétés de la tert-butyl-5 diméthyl-3,3 cycloheptanone
Authors: Richer Jean-Claude , Bisson Robert
Published: May 2006

not available
Concerning the problems involved with use of external references for variable temperature chemical shift measurements
Authors: Blackburn B. J. , Hruska Frank E. , Smith Ian C. P.
Published: May 2006

The importance of making bulk susceptibility corrections to nuclear magnetic resonance chemical shifts measured versus an external reference is emphasized. The special significance of this correction for variable temperature studies is demonstrated by comparing data obtained with external and internal references for uridine-5′-phosphate. Opposite trends in chemical shift and inaccurate activation energies can result.
Aromatic nucleophilic substitutions. Reactions of chloro- and nitro-substituted benzenes
Authors: Radhakrishnamurti P. S. , Sahu Janardan
Published: May 2006

The kinetics of the reaction of 2,4-dinitro-1-chlorobenzene with various aromatic bases to give 2,4-dinitrodiphenylamines have been studied in alcohol, alcohol–acetonitrile, alcohol–dimethylformamide, and alcohol – dimethyl sulfoxide mixtures. No base catalysis has been observed under these conditions. ρ Values have been computed. In the reaction of o-chloro- and p-chloronitrobenzene with hydroxide in 50% dimethyl sulfoxide, the reactivity of both the isomers has been found to be identical, in contradiction to the previously reported observations.
Spectra of Co(II) in molten nitrates and dimethyl sulfone
Authors: Fung K. W. , Johnson K. E.
Published: May 2006

The electronic spectrum of Co(II) in LiNO3–KNO3, AgNO3–KNO3, and dimethyl sulfone containing excess LiNO3–KNO3 resembles that of the dodecahedral [Co(NO3)4]2− ion and parameters for this symmetry and the approximation Td are calculated. Co(ClO4)2 yields an octahedral species in dimethyl sulfone.
Chemistry of metal hydrides. VII. An iridium(III) carbonyl cation and the formation of iridium(III) hydridocarbonyls
Authors: Clark H. C. , Mittal R. K.
Published: May 2006

IrCl3(PEt3)3 is readily converted to IrHCl2(CO)(PEt3)2 by treatment with carbon monoxide in hot acetone, ethanol, or 2-methoxyethanol. Perchlorate, tetrafluoroborate, and tetraphenylborate salts containing the [IrCl2(CO)(PEt3)3]+ cation have been prepared, but attempts to obtain salts containing the [IrHCl(CO)(PEt3)3]+ cation give only the neutral hydride, IrHCl2(CO)(PEt3)2. The reactions of [IrCl2(CO)(PEt3)3]+ with ethanol, water, lithium aluminum hydride, aqueous potassium chloride solution, and sodium alkoxides are described.
Mechanism of silicon hydride addition to hydridocarbonyltris(triphenylphosphine) iridim(I)
Authors: Harrod J. F. , Smith C. A.
Published: May 2006

not available
Polyatomic cations of selenium. III. Compounds of the Se82+ cation
Authors: Gillespie R. J. , Ummat P. K.
Published: May 2006

The preparation and characterization of the compounds Se8(Sb2F11)2 and Se8(AsF6)2 are described. Both compounds are shown to contain the Se82+ cation.
Synthesis of an analog of ochrobirine
Authors: Manske R. H. F. , Ahmed Quazi A.
Published: May 2006

An analog of ochrobirine in which one of the methylenedioxy groups is absent has been synthesized.
Synthesis and characterization of cyclam complexes of rhodium(III)
Authors: Bounsall E. J. , Koprich S. R.
Published: May 2006

A series of complexes of the type Rh(cyclam)X2+ and Rh(cyclam)XYn+ have been prepared and characterized, where cyclam represents 1,4,8,11-tetraazacyclotetradecane and X and Y represent OH−, H2O, Cl−, Br−, I−, N3−, NCS−, and NO2−. The infrared and electronic spectra are discussed with respect to assignment of the cis and trans isomers, the linkage isomers, and the Rh–ligand stretching frequencies above 250 cm−1. The thermodynamic trans effect is related to shifts in the Rh–ligand stretching frequencies. The intensities of the d–d transitions are related to distortion of the octahedral field to support the cis and trans assignments, and compared to show the decrease in bond constraint for propylene linkages in place of ethylene. Steric constraint accounts for the single case of stereoisomerization by cis-Rh(cyclam)I2+.
Radiolysis of air and nitrogen–oxygen mixtures with intense electron pulses: determination of a mechanism by comparison of measured and computed yields
Authors: Willis C. , Boyd A. W. , Young M. J.
Published: May 2006

Air and other mixtures of nitrogen and oxygen containing from 0.1 to 100% oxygen have been irradiated with single, 0.12 Mrad electron pulses at a dose rate of 2 × 1026 eV g−1s−1. The major product formed in these irradiations is ozone. For air from 400–1500 Torr, G(O3) = 10.3 ± 0.5, the addition of SF6 reduces this by 5.8 ± 0.5 G units. The yield of ozone from other nitrogen–oxygen mixtures varies with the concentration of oxygen. At both 700 and 1500 Torr total pressure for 1 Torr of O2, G(O3) ≈ 4. This increases with oxygen concentration to a maximum of G(O3) = 12.8 for pure oxygen. For all the above conditions the yield of nitrogen dioxide is below the limits of detection.A mechanism is proposed based on known possible ionic and neutral reactions and their rate constants. Detailed computer calculations using this mechanism give results which compare well with the experimental yields. These results are consistent with an assumed yield of G(N) = 6 from processes involving neutral species in the radiolysis of pure nitrogen.
Pulse radiolysis of nitric oxide in aqueous solution
Authors: Seddon W. A. , Young M. J.
Published: May 2006

not available
On the occurrence of ononin in Thermopsisrhombifolia (Nutt.) Richards
Authors: Benn M. H. , Watanatada Churai
Published: May 2006

Ononin, formononetin-O-β-D-glucopyranoside, was isolated from Thermopsisrhombifolia (Nutt.) Richards. It seems very probable that this is the substance A which Marion and Manske isolated from this plant, and that their substance B was formononetin itself.
Organic and biological spectrochemical studies. XXVIII. Electron spin resonance spectra of some polynuclear aromatic hydrocarbon ions
Authors: Cooper J. T. , Forbes W. F. , Robinson J. C.
Published: May 2006

The electron spin resonance spectra are presented for the anions and cations of the polynuclear aromatic hydrocarbons anthanthrene, benz[ghi]perylene, benz[e]pyrene, dibenz[fg,op]naphthacene, and dibenz[a,c]triphenylene. The cation of dibenz[fg,op]naphthacene is shown to form a dimer under certain conditions.The usefulness of a new oxidizing agent for the production of the cations, boron trichloride, has been investigated and was found to afford comparable spectra to boron trifluoride, using sulfur dioxide as solvent.
Solid–liquid equilibrium in the system chlorine dioxide – chlorine
Authors: Kepinski J. , Kalucki K.
Published: May 2006

The method of preparation and analysis of liquid mixtures of chlorine dioxide and chlorine is described. The mixtures of chlorine dioxide and chlorine were found to be completely miscible. The freezing points were determined by using the dynamic method of measurement and the extrapolation procedure. An eutectic point was found to exist at −101.6 ± 0.1 °C. The eutectic solution contains 1.6 mole % of chlorine dioxide.
Cusp constraints for atomic wavefunctions
Authors: Chapman J. A. , Chong D. P.
Published: May 2006

A hierarchy of cusp constraints, from necessary to sufficient, is examined. A flexible approach of cusp-satisfying orbitals is proposed. This is tested on some simple wavefunctions for the ground state of lithium. It is found that cusp-satisfying wavefunctions give good values for the spin as well as electron densities at the nucleus.
Vibrational spectra of some perfluoro-arsenates and antimonates with nitrogen heterocations
Authors: Qureshl A. M. , Aubke F.
Published: May 2006

The infrared spectra from 4000–250 cm−1 and the laser Raman spectra of NOAsF6, NO2AsF6, N2F3AsF6, F2NOAsF6, NOSbF6, NO2SbF6, N2F3Sb2F11, and F2NOSb2F11 are recorded. Eight of the nine fundamentals expected for the N2F3+ cation can be observed and are tentatively assigned. The vibrational spectra of the MF5 adducts are in agreement with an ionic formulation; however, the mutual exclusion rule for infrared and Raman active vibrations appears to be relaxed and one of the fundamentals v5 [F2g] is split into a doublet in almost all cases.
Structure of a diazecine derivative from the condensation of phthaloyl chloride with ethylenediamine
Authors: Wolfe Saul , Hasan S. K.
Published: May 2006

The high dilution condensation of phthaloyl chloride with ethylenediamine has afforded not the benzodiazocine derivative 14, as reported earlier, but a more complex compound (17) which has been found to be a bridged dibenzodiazecine derivative. Treatment of 17 with ethanol causes alcoholysis of two of the four bridgehead lactam linkages. On heating, 17 isomerizes by a double ring → chain rearrangement to 1,2-diphthalimidoethane. The n.m.r. spectrum of 17 is discussed in terms of three possible conformations of the ten-membered ring.
Chlorination of Pyrroles. Part I
Authors: Durham D. G. , Rees A. H.
Published: May 2006

Formylation of 1-phenylpyrrole gave mainly the 2-aldehyde which was converted to the methyl ester. Chlorination produced the 4- and 5-monochloro, the 4,5-dichloro and the 3,4,5-trichloro derivatives and 2-methoxycarbonyl-5-oxo-1-phenyl-2,3,4-trichloro-3-pyrroline which were identified spectroscopically. The mass spectral cracking patterns of the chloropyrrole esters have been interpreted.
Nucleophilic Substitution on S4N4. Reactions with Benzylamines
Authors: Sasaki Yukihiko , Olsen Fredric P.
Published: May 2006

Reactions of benzylamines with tetrasulfur tetranitride lead to benzylidenimine polysulfides, ammonia, N-benzylidene benzylamines, and some free sulfur. The stoichiometric equation has been established. The reaction is quite sensitive to structural changes and appears limited to ring substituted benzylamines. The benzylidenimine polysulfides undergo thermal decomposition to sulfur and triphenyl-s-triazine and react with benzylamine to give benzylammonium polysulfides, ammonia, and N-benzylidene benzylamine. The benzylammonium polysulfides decompose in air to sulfur, hydrogen sulfide, and benzylammonium thiosulfate.
The Decomposition of Benzoyl Hypochlorite in the Presence of Metal Ions
Authors: Bunce N. J. , Urban L. O.
Published: May 2006

The decomposition of benzoyl hypochlorite, the intermediate in the Hunsdiecker reaction between chlorine and silver benzoate, is accelerated by light and by azobisisobutyronitrile (AIBN), but not by transition metal ions. The molar yield of the chlorobenzene produced in the decomposition increases as the temperature of the reaction mixture is raised, but is independent of whether or not the reaction is promoted by light or AIBN. It is suggested that this variation in the yield is a result of the readier decarboxylation at higher temperatures of the benzoyloxy radicals which are believed to be intermediates in the decomposition process. No such pronounced effect of temperature on the yield of halides from aliphatic silver carboxylates has been observed, presumably because aliphatic acyloxy radicals decarboxylate readily even at low temperatures.
Kinetics of the Reaction of Atomic Hydrogen with Vinyl Chloride
Authors: Tanner J. S. , Jamieson J. W. S.
Published: May 2006

The reaction of hydrogen atoms, produced by electric discharge, with vinyl chloride vapor has been studied at four widely different temperatures. Since the maximum yields of HCl at both 328 and 494 °C exceeded the flow rates of atomic hydrogen, the reaction was observed to have limited chain characteristics. The products were hydrogen chloride, ethylene, methane, and ethane. The specific reaction rate for HCl production was found to be about [Formula: see text] and that for production of ethylene plus ethane was found to be about [Formula: see text].
Reactions of Sodium N,N-Diethyldithiocarbamate with the Chlorides and Bromides of Niobium(V), Tantalum(V), and Protactinium(V)
Authors: Heckley P. R. , Holah D. G. , Brown D.
Published: May 2006

Reactions between niobium(V), tantalum(V), and protactinium(V) chlorides and bromides and sodium N,N-diethyldithiocarbamate (Nadtc) have been examined in non-aqueous, non-oxygenated organic solvents. Complexes obtained are of the types Mdtc4X, Mdtc3X2, Mdtc3S, Mdtc2X3, and Mdtc2X3.nC6H6 (n = 0.7–1.0); not all complexes have been isolated for each metal. Within each group the niobium(V) and tantalum(V) complexes are isostructural; possible structures are discussed in the light of results from infrared (i.r.) and nuclear magnetic resonance (n.m.r.) spectra, molecular weight, and electrical conductivity measurements.
The Silver–Calcium System
Authors: Campbell A. N. , Wood W. H. W.
Published: May 2006

The Ag–Ca system has been reinvestigated over the composition range 50–100 atomic % Ca, by differential thermal analysis and high temperature X-ray powder diffraction. Our results are in good agreement with those of Alexander et al. (1) and those of Pascal et al. (2) in the region 50–59 atomic % Ca, but the peritectic claimed by Alexander et al., lying at 50% Ca and 598 °C, appears not to exist, according to our DTA and X-ray results. Here and elsewhere our results substantiate those of Pascal et al. We also find that the compound AgCa3 is formed peritectically, and not congruently as suggested by Alexander et al.
Infrared Studies of Water in Crystalline Hydrates: Sodium Nitroprusside Dihydrate, Na2[Fe(CN)5NO]•2H2O
Authors: Holzbecher Michaela , Knop Osvald , Falk Michael
Published: May 2006

Infrared spectra of polycrystalline Na2[Fe(CN)5NO] 2H2O at different degrees of deuteration were studied as a function of temperature. The single peaks observed for the bending fundamentals of isotopically dilute H2O and D2O show that all the water molecules are equivalent, as required by Manoharan and Hamilton's structure determination; the doublets observed for the three fundamentals of isotopically dilute HDO show that the water molecules are asymmetric. Doublet separation decreases gradually with increasing temperature, indicating decreasing asymmetry. The water molecule appears to orient itself so as to maximize the strength of one [Formula: see text] bond, while the other OH group interacts only very weakly with another CN group. The hitherto unknown extent to which the nitroprusside ion deviates from the ideal C4v symmetry has been estimated from the 13C14N stretching spectrum. The 15N16O and 14N18O stretching spectrum was used to confirm that only one type of NO group is present in the crystal, and hence that all nitroprusside ions are equivalent.
Proton Magnetic Resonance Investigation of Some Weak Interactions Between Naphthalene and Alkyl Iodides in Carbon Tetrachloride
Authors: Sahai R. , Lin S. H.
Published: May 2006

A p.m.r. investigation of the interactions between naphthalene and alkyl iodides has been reported. The equilibria, the heats and the entropy changes for the complexation, and the chemical shifts of the acceptor protons in the pure complex have been determined. A crude dipole model for these interactions has been suggested.
The Thermal Pressure and Energy–Volume Coefficients of the Methyl Alcohol – Water and t-Butyl Alcohol – Water Systems
Authors: Macdonald Digby D. , Hyne J. B.
Published: May 2006

Thermal pressure and energy–volume coefficients have been determined for various methyl alcohol – water and t-butyl alcohol – water mixtures at several temperatures in the range 19–55 °C. The energy–volume coefficient is found to pass through a maximum at 0.3–0.4 mole fraction methyl alcohol and 0.1 mole fraction t-butyl alcohol. This behavior is consistent with the average intermolecular distance passing through a minimum in both systems at the corresponding solvent compositions. The relationship between the energy–volume coefficient, the cohesive energy density, and the structure of aqueous binary systems is examined. The temperature dependence of the thermal pressure coefficient is discussed in terms of the effect of temperature on the susceptibility of the entropy of the two systems to isothermal expansion.
Kinetics and Mechanism of Hydrogen Exchange in the 2,4,6-Trihydroxybenzenonium Ion
Authors: Kresge A. J. , Chiang Y. , Shapiro S. A.
Published: May 2006

The n.m.r. line-broadening method was used to measure rates of hydrogen exchange in the 2,4,6-trihydroxybenzenonium ion (carbon-protonated phloroglucinol) in a series of concentrated sulfuric and perchloric acid solutions. Comparison of separately determined rates of exchange of protons in the methylene and vinyl groups of this ion allows a concerted mechanism for the exchange reaction to be excluded and shows that exchange must occur through intermediate formation of completely deprotonated 1,3,5-trihydroxybenzene. This assignment of reaction mechanism allows transformation of the data into deprotonation rate constants, which, together with previously measured positions of equilibrium, permit estimation of specific rates of protonation of 1,3,5-trihydroxybenzene, k+; the latter are in good agreement with the rate of aromatic hydrogen exchange of 1,3,5-trihydroxybenzene measured by an isotopic tracer method at lower acidities. The kinetic acidity dependence of k+ is unusually shallow; this, coupled with the much steeper acidity dependences of other aromatic protonation reactions, serves to reinforce the growing realization that there is no unique relationship between kinetic acidity dependence and reaction mechanism.
121Sb Mössbauer: Antimony—Fluorine Systems
Authors: Birchall T. , DellaValle B.
Published: May 2006

121Sb Mössbauer data are presented for NaSbF4, KSbF4, KSb2F7, K2SbF5, KSbF6, CsSb2F11, and (NH4)2SbCl5. Attempts are made to rationalize the data in terms of known structural parameters.
Ozonation of Naphthalene with Water as Participating Solvent. Preparation of o-Phthalaldehyde
Authors: Sturrock Murray G. , Cravy Betty J. , Wing Virginia Allen
Published: May 2006

The water in aqueous acetone solutions acts as a participating solvent in the reaction of naphthalene with ozone forming hydroperoxy intermediates which are reduced to o-phthalaldehyde by conventional agents. The results are markedly different from those obtained in anhydrous solvents. Yields of product requiring no purification are 63%.
A Novel Nucleophilic Displacement of Benzoate by Sulfur During Thiation of 3-Deazauridine Tribenzoate
Authors: Robins Morris J. , Currie Bruce L. , Robins Roland K. , Broom Arthur D.
Published: May 2006

Thiation of 3-deazauridine tribenzoate [4-hydroxy-1-(2,3,5-tri-O-benzoyl-β-D-ribofuranosyl)-2-pyridone] (1a) with phosphorus pentasulfide in moist β-picoline followed by debenzoylation gave 2-mercapto-1-(2-deoxy-β-D-arabinofuranosyl)pyridine-4-thione-S2 → 2′-cyclonucleoside (2b). Thus, replacement of the heterocyclic oxygens by sulfur followed by a novel nucleophilic displacement of benzoate by mercaptide in the hot basic solution must have occurred.
The Reaction of 5-Unsubstituted-1,2-Dithiole-3-thiones with some Activated Acetylenes
Authors: McKinnon D. M. , Buchshriber J. M.
Published: May 2006

5-Unsubstituted 1,2-dithiole-3-thiones undergo addition reactions with dimethyl acetylenedicarboxyl-ate and dibenzoylacetylene to give amorphous 2-thioformylmethylene-1,3-dithioles. In certain cases these may undergo further addition of activated acetylene to give thiopyranspiro-1,3-dithioles, but may also lose sulfur to give bis-1,3-dithiolylidene-2-butenes, which are probably formed via initial dimerization of the thioformylmethylenedithioles. The stereochemistry of the products is discussed briefly.
Revisions of Structural Assignments for l-Methyl-(3 and 5)-amino-4-nitropyrazoles and Related Compounds
Authors: Khan Misbahul Ain , Lynch Brian M.
Published: May 2006

Amino proton chemical shifts recorded for the compounds described as 5-amino-1-methyl-4-nitropyrazole and the 3-amino isomer (3) are inconsistent with charge densities calculated from simple H.m.o. treatments.Unequivocal synthesis of 5-amino-1-methyl-4-nitropyrazole from 5-amino-1-methylpyrazole proves that the assignments should be interchanged; the structures of compounds derived from these amino-nitropyrazoles are revised accordingly.
Proton Magnetic Resonance Studies of Ionic Solvation in Ion-exchange Resins. Part III. Multivalent Counterions
Authors: Sharma H. D. , Subramanian N.
Published: May 2006

The p.m.r. spectra of Dowex AG 50W, X8, resins containing multivalent counterions have been measured. The ionic molal shifts in the exchanger phase are compared with those reported in homogeneous aqueous solutions. The spectral results are consistent with the concentrated electrolyte model of ion-exchange resins. Concentration and temperature dependence of proton chemical shifts in multivalent ionic forms of the resin suggests that ion association at high crosslinkages is more pronounced for counterions with high charge densities. The shapes of the shift-molality plots are explained by postulating that, at high crosslinkages, Mg2+ ion and the fixed —SO3− group form "contact-ion pair" while the formation of "solvent-separated ion pair" is important in Be2+ and Al3+ forms of the resin. The anomalous trend in the hydration number values for magnesium and aluminum resinates can be understood as due to the long-range ordering of water structure in the presence of structure-forming ions. The p.m.r. spectra of resin–methanol system have been recorded at room temperature and at −65 °C. Failure to observe the resonance signal due to the cationic solvation shell at low temperature is attributed to the high degree of ion association under the conditions prevailing in the resin medium.
Etude de propriétés hydrodynamiques de solutions de polymères en mauvais solvants
Authors: Ho-Duc Nga , Daoust H. , Blssonnette F.
Published: May 2006

Sedimentation coefficients (ultracentrifuge), second virial coefficients (light scattering) and intrinsic viscosities have been measured at various concentrations near the θ-point for solutions of polystyrene in cyclohexane and of polyisobutylene in ethyl heptanoate. The results have been analyzed in the light of several current theories, but are correlated satisfactorily only by the theory of Pyun and Fixman.
The Dipole Moment Derivative of the Hydrogen Bond in Ice
Authors: Whalley E.
Published: May 2006

The dipole moment derivative of the hydrogen bond in ice has been calculated assuming that the molecules can be represented as non-overlapping polarizable charge distributions characterized by dipole and quadrupole moments. The value is 0.1 electron charges which is about one third of the experimental value obtained from the far-infrared spectrum. The model predicts therefore only about one tenth of the experimental integrated intensity from which the effective charge was derived. Most of the intensity must therefore be due to specific hydrogen-bond interactions.
Dielectric Studies. Part XXXII. Detection of High Frequency Absorption from Microwave Data
Authors: Martin G. D. , Walker S.
Published: May 2006

The dielectric constants and losses have been determined for solutions of o-hydroxyacetophenone, 1-chloro-and 1-bromonaphthalene and 2-chloro- and 2-bromonaphthalene in dilute solutions of 15 °C involving a nonpolar solvent. Either seven or eight microwave frequencies were employed over a wide range from about 1 to 145 GHz, and the relaxation times of the molecules were such that the high frequency side of the Cole–Cole plot near the dielectric constant at high frequencies (ε∞) was well defined. For these polar solutes in nonpolar solvents no high frequency deviations from the Cole–Cole plot are apparent in the plot itself based solely on microwave data. In a few cases the distribution parameter was negligible (less than 0.03) and in one case it was zero. In all cases a Cole linear plot and also a Brot plot revealed the existence of additional absorption to that contributed by molecular relaxation. Such additional absorption would have been difficult to be certain of from the Cole–Cole plot alone when the distribution parameter was either negligible or very small. The frequency points at about 70 and 145 GHz are invaluable in detecting such additional high frequency absorption contributions.
Normal Coordinate Calculations of the Vibrations of Methylene Cyclopropane-h6 and -d6
Authors: Bertie J. E. , Sunder S.
Published: May 2006

not available
Intermolecular Potentials from Differential Cross Sections: Ar + Ar
Authors: Kalos Ferenc , Grosser Arthur E.
Published: May 2006

The angular distribution of Ar + Ar scattering at E = 9.16 × 10−14 erg was measured out to the rainbow pattern (supernumerary rainbow and part of the rainbow peak) by the crossed molecular beam technique, with mass spectrometric detection. This distribution was compared to calculated differential cross sections. Total cross sections, and spectroscopic constants for Ar2 were also calculated. The trial potentials were L.J.-12,6, LJ.-20,6, a modified Lennard–Jones potential (L.J.-14,12,8,6) and the Bobetic–Barker potential. The Bobetic–Barker potential is the one most consistent with cross section and spectroscopic experiments.
Kinetics of the Mercury-Photosensitized Decomposition of Neopentane. Part I. The Overall Mechanism
Authors: Furimsky E. , Laidler K. J.
Published: May 2006

The mercury-photosensitized decomposition of neopentane was investigated from 230 to 335 °C, and at pressures from 3 to 280 Torr. The following were identified as primary products and their initial rates of formation measured over a range of conditions: H2, CH4, C2H6, i-C4H8, neohexane and dineopentyl. The results are explained in terms of a mechanism in which the primary step involves the split of neopentane (Nptn) into the neopentyl radical (Nptl) and H; Nptl then undergoes further reactions including a split into i-C4H8 + CH3. Estimates are made of the free-radical concentrations at various temperatures and pressures. A simplified steady-state treatment is worked out and is shown to explain the pressure dependence of the rates of formation of the various primary products.
Kinetics of the Mercury-Photosensitized Decomposition of Neopentane. Part II. Reactions of the Methyl and Neopentyl Radicals
Authors: Furimsky E. , Laidler K. J.
Published: May 2006

The results of Part I are further analyzed with reference to certain of the elementary free-radical processes occurring. A fall-off in the methyl radical combination is observed at low pressures. Comparison of this process with the CH3 + neopentane abstraction yields for the latter an activation energy of 11.5 kcal/mol and a frequency factor of 4.9 × 1011 cc mol−1 s−1. The relative importance of CH3 + neopentyl and neopentyl + neopentyl is compared. The decomposition of the neopentyl radical into i-C4H8 + CH3 shows a fall-off at low pressures; the limiting activation energy at high pressures is 29.0 kcal/mol, while that at low pressure is 17.1 kcal/mol. The former value leads to 6.7 kcal/mol for the heat of formation of the neopentyl radical at 25 °C, to 21.3 kcal/mol for the heat of its dissociation into i-C4H8 + CH3, and to 98.5 kcal/mol for the heat of dissociation of neopentane into neopentyl + H. Entropy values are also calculated in an approximate manner.
Infrared and Raman Spectra of Single Crystals of Anhydrous Strontium Formate
Authors: McQuaker N. R. , Harvey K. B.
Published: May 2006

The infrared absorption of single crystals of anhydrous strontium formate has been measured in the region 4000 to 500 cm−1. The internal fundamentals of two sets of crystallographically non-equivalent types of formate ions are identified. Frequencies of external fundamentals are tentatively inferred from absorption bands appearing in the second order spectrum. Measurement of laser excited Raman spectra in the region 700–10 cm−1 has yielded assignments for all of the expected translational modes. None of the librational modes were observed.
Magnetic Susceptibilities of 2T2 Ions. Part 1
Authors: Westland Alan D.
Published: May 2006

An expression for the magnetic susceptibility of octahedral d1 complexes is derived exactly in terms of an orbital reduction factor k taking into account the presence of the formal 2E excited state. Sample calculations show that the improved expression gives results for susceptibility which are lower at times by several percent from those given by previous expressions. The results given by Figgis using Kotani's method are adequately precise when the spin–orbit coupling constant is no larger than ~0.1 Dq.
Reactions of Ethylene with Rhodium (III) Chloride. Part III. The Catalytic Oxidation of Ethylene to Acetaldehyde in Aqueous Hydrochloric Acid Solutions Containing Pentachloroaquorhodate(III)
Authors: James B. R. , Kastner M.
Published: May 2006

In the presence of iron(III) or other oxidants, aqueous acid chloride solutions of RhCl5(H2O)2− catalyze under mild conditions the oxidation of ethylene to acetaldehyde. The kinetics of the reaction measured by gas-uptake techniques indicate the presence of both ethylene dependent and independent paths. Besides fully protonated anions, hydroxy species such as RhCl5 (OH)3− and RhCl4(OH)(H2O)2−, although present in very small concentrations, are significantly reactive towards ethylene. A mechanism, based on that postulated for a similar palladium(II) system in the well-known Wacker process, is presented. Under our reaction conditions the slow steps in the rhodium system involve formation of π-complexes in the ethylene dependent paths and the formation of tetrachlororhodate(III) complexes in the ethylene independent paths. Iron(III) regenerates the rhodium(III) catalyst by oxidation of the rhodium(I). Rate constants are estimated for the various reaction paths.
Analysis of 134Cs Isomer Ratios in the Fission of 237Np with Protons in the Energy Range 20–85 MeV
Authors: Rao C. L. , Yaffe L.
Published: May 2006

An analysis has been made of the isomer ratio, σm/((σm + σg) for 134Cs isomers formed in the fission of 237Np by protons of energies 20–85 MeV. Compound nucleus formation was assumed up to a bombarding energy of 50 MeV, with direct interaction as the mechanism at higher energies. Values of the root-mean-square angular momentum of [Formula: see text] at 20 MeV and [Formula: see text] at 60–85 MeV bombarding energy agree with the experimental results. The results are consistent with the hypothesis that angular momentum is generated in the fission process.
Evaluation of the Binding Constants, Bound Chemical Shifts, and Stoichiometry of Lanthanide–Substrate Complexes
Authors: Armitage Ian , Dunsmore G. , Hall L. D. , Marshall A. G.
Published: May 2006

A theoretical analysis of the equilibrium between a lanthanide shift reagent, L, and a substrate, S, is presented. When [Formula: see text] then a plot of [S]0vs. (1/δ) at constant [L]0 gives a straight line whose slope is [L]0ΔB and whose y-intercept is −{(1/KB) + [L]0}, where KB is the equilibrium binding constant, δ is the induced chemical shift, and ΔB is the bound chemical shift. A more general and accurate solution using a computer programme is applicable for all ratios of [L]0/[S]0. It is also shown that the conventional procedure for evaluating ΔB leads to varying values for ΔB that are generally too small, even under the most optimal conditions. Eu(DPM)34 has a KB of ca. 34.21 mol−1 with n-propylamine and KB of ca. 9.71 mol−1 with neo-pentanol. These values increase by at least 10-fold (to ≥ 1001 mol−1) for the corresponding complexes with Eu(FOD)34 shift reagent. However, the bound chemical shifts for the Eu(FOD)3 complexes are nearly the same as for the Eu(DPM)3 complexes. Finally, it is shown definitively that the association between Eu(DPM)3 and either n-propylamine or neo-pentanol has 1:1 stoichiometry; with Eu(FOD)3 a tentative assignment of 1:1 stoichiometry can be made.
An Electron Spin Resonance Study of the Radical Cations Derived from Dialkoxybiphenyls
Authors: Sullivan Paul D. , Norman Louis J.
Published: May 2006

The e.s.r. spectra of the cation radicals of various alkyl substituted 4,4′-dihydroxybiphenyls have been studied. These spectra give information regarding the molecular motions occurring in these compounds.
An Addition Reaction of Indane with Nitric Acid in Acetic Anhydride
Authors: Fischer A. , Greig C. C. , Wilkinson A. L. , Leonard D. R. A.
Published: May 2006

cis- and trans-5-Acetoxy-7a-nitro-5,7-dihydroindane are formed as well as the 4- and 5-nitroindanes when indane is reacted with nitric acid and acetic anhydride. These adducts both decompose on standing by loss of nitrous acid forming 5-acetoxyindane. The cis isomer is obtained in greater amount and it undergoes elimination less readily than the trans.
Thiohydantoins. IX. Tautomerism of some Methylation Products
Authors: Edward J. T. , Liu J. K.
Published: May 2006

The methylation product of 5,5-pentamethylene-2-thiohydantoin has been shown by u.v. and i.r. spectral studies to exist predominantly as 2-methylthio-4,4-pentamethylene-2-imidazolin-5-one in chloroform or cyclohexane, and as 2-methylthio-5,5-pentamethylene-2-imidazolin-4-one in water. The tautomerism of the methylation product of 5,5-pentamethylene-2,4-dithiohydantoin exhibits a similar sensitivity to solvent.
Collisional Deactivation Rates of Electronically Excited Molecular Ions. III.
Authors: Mackay G. I. , Anglesey J. P. , March R. E.
Published: May 2006

Electron beam excitation of oxygen was utilized to produce ions in the [Formula: see text] state. Rate constants for the deactivation of [Formula: see text] for each of O2 and N2 were determined. Charge transfer is a possible mode of deactivation.
CN Emission in Active Nitrogen. II. The Role of Energy Transfer and Atom Transfer Reactions in CN(X2Σ+) Excitation
Authors: Provencher G. M. , McKenney D. J.
Published: May 2006

A simplified mechanism is presented for excitation of ground state CN(X2Σ+) formed from carbonaceous impurity in flowing N2 subjected to a microwave discharge. Analysis of absolute intensity data from spectrometer recordings of CN(B2Σ+ → X2Σ+) violet band emission enabled order of magnitude estimates of rate constants for CN(X2Σ+) excitation by energy transfer from vibrationally excited ground state nitrogen, [Formula: see text][Formula: see text]and formation of electronically excited NCN* in a three body reaction[Formula: see text]Energy transfer from [Formula: see text] is shown to be a minor source of excitation of CN to radiative levels. N2(A) is a source of vibrationally excited ground state nitrogen, [Formula: see text] which in turn excites CN. Vibrational population profiles under all conditions in this work are shown to be primarily a function of [Formula: see text] Evidence for the participation of the A2Π state of CN is shown in the population maxima at ν = 4 and 10 of the B2Σ+ state.