bluuebunny/crossref_metadata_2025 huggingface dataset:
Equilibration d'imines cyclaniques
Authors: Richer Jean-Claude , Perelman David
Published: May 2006

not available
Infrared spectrum of HDO in water and in NaCl solution
Authors: Wyss Hans R. , Falk Michael
Published: May 2006

The molar absorptivity of dilute HDO in water and in aqueous NaCl solutions was determined at temperatures between 10 and 85° in the spectral region from 4000 to 2000 cm−1.The infrared band profiles for the OH and OD stretching fundamentals are single-peaked and devoid of shoulders, in contrast to the high-frequency shoulders recently observed in the Raman spectrum. It is shown that such shoulders do not contradict a single-peaked distribution of OH oscillators with respect to inter-molecular geometry. Absence of resolvable sub-bands in the spectrum of HDO in concentrated salt solutions indicates a wide distribution of ion–H2O interactions, akin to the distribution of H2O–H2O interactions in water.
Cumulative yields in the 14 MeV neutron fission of 232Th and 238U in the symmetric region
Authors: Gevaert L. H. , Jervis R. E. , Sharma H. D.
Published: May 2006

The radiochemical yields of molybdenum-99, ruthenium-103 and -105, palladium-109 and -112, silver-111 and -113, cadmium-115, and tin-121 and -125 formed in the 14 MeV fission of thorium-232 and uranium-238 have been determined using a low background Geiger–Muller counter, NaI(Tl) crystal, and Ge(Li) detector. The absolute mass yield for molybdenum-99 has been obtained using a copper monitor for neutron flux and for the other nuclides using molybdenum-99 as an internal standard. The mass distribution curves derived from the chain yields, in the symmetric region show the presence of a third peak in thorium-232, and only the familiar two peaks for uranium-238 in the asymmetric region. By comparison of normalized cumulative mass yields from this study with prompt fission yield data, the average number of prompt neutrons emitted from fission fragments has been obtained as a function of mass in 238U + n fission. It appears that there are two regions of enhanced neutron emission in the mass range 103–128, and that the heavy fragments emit more neutrons than the light ones.
Rearrangement of a steroidal 14β-hydroperoxide. Cleavage of ring D
Authors: Afonso Adriano
Published: May 2006

The rearrangement of 14β-hydroperoxy-Δ15-androsten-3β-ol-17-one 3-acetate (2) with boron trifluoride etherate affords 3β,15-dihydroxy-14,15-seco-Δ15-5α-androstene-14,17-dione 3-acetate (4a). The decarbonylation of the rearrangement product was studied.
The 35Cl nuclear quadrupole resonance spectra of BCl3 and several of its amine and nitrile complexes
Authors: Kaplansky M. , Whitehead M. A.
Published: May 2006

The 35Cl nuclear quadrupole resonance frequencies of BCl3, two amine complexes, and five nitrile complexes of BCl3 are reported for 77 °K. Two molecular orbital theories, BEEM-π and CNDO, are used to interpret the frequencies.The temperature dependences of the 35Cl nuclear quadrupole resonance frequencies of B-trichloroborazole are reported.
Nuclear magnetic resonance studies of solid methylammonium halides
Authors: Tsau J. , Gilson D. F. R.
Published: May 2006

Wide-line nuclear magnetic resonance studies of methylammonium chloride, bromide, and iodide and their partially deuterated analogues show that second-moment and line-width transitions occur which can be interpreted as due to molecular reorientation about the C—N axes. In the bromide and iodide salts this motion persists below 77 °K.
Synthesis, resolution, and absolute configuration of 1-phenyl-1-methyl-1-silacyclohexanone-2
Authors: Brook A. G. , Kucera H. W. , MacRae D. M.
Published: May 2006

The synthesis and resolution of 1-phenyl-1-methyl-1-silacyclohexanone-2 by oxidative hydroboration of the related silacyclohexene to the silacyclohexanol, resolution of this via the strychnine salt of the phthalate half-ester, and subsequent oxidation of the silacyclohexanol to the silacyclohexanone is described. The carbon analog 1-phenyl-1-methylcyclohexanone-2 was also synthesized in optically active form. The (+)-enantiomers of the two ketones had similar optical rotatory dispersion curves, presenting convincing evidence for the identity of their configurations, and the carbon compound could be degraded without affecting the asymmetric center to (−)-(R)-2-phenyl-2-methylhexandioic acid, thereby establishing the absolute configurations of both compounds.
Refinement of the structure of Mg2As2O7
Authors: Calvo C. , Neelakantan K.
Published: May 2006

The crystal structure of Mg2As2O7 has been refined by full matrix least squares procedures using 587 observed reflections. The structure of Mg2As2O7 is of the thortveitite type, as reported by Łukaszewicz, with space group C2/m and unit cell dimensions a = 6.567(2) Å, b = 8.524(4) Å, c = 4.739(1) Å, β = 103.8(1)°, and Z = 2. The As—O—As group in the anion appears to be linear but the central oxygen atom undergoes considerable disorder in the plane perpendicular to this group. The AsO bond distances uncorrected for thermal motion are 1.67 Å for the As—O(—As) bond and 1.66 and 1.65 Å for the terminal As—O bonds. The final R value obtained is 0.088.
Synthesis of the deotero-specific 4-d and 6-d methyl 3,5-dinitrosalicylates
Authors: McCubbin J. A. , Moir R. Y. , Neville G. A.
Published: May 2006

The synthesis is described of several specifically labelled deuterium derivatives of salicylic acid needed for the study of long-range coupling and in infrared studies of aromatic conformation.
Signs of methyl–methyl proton spin–spin coupling constants in xylene derivatives (interbenzylic coupling)
Authors: Macdonald C. J. , Reynolds W. F.
Published: May 2006

The signs of the intermethyl proton spin–spin coupling constants in ortho, meta, and para xylene derivatives (interbenzylic coupling) have been determined by double resonance techniques. [Formula: see text] [Formula: see text] and [Formula: see text] are positive, negative, and positive, respectively, in agreement with the predictions of theories based on σ–π interactions. The magnitudes of the coupling constants are discussed in terms of the values predicted by these theories.
Nuclear magnetic resonance spectra of the epihalohydrins. I. Signs of long-range spin–spin coupling constants in epichlorohydrin
Authors: Macdonald. C. J. , Schaefer T.
Published: May 2006

The complete analysis of the proton magnetic resonance spectrum of epichlorohydrin as 10 mole% solutions in benzene and in acetonitrile is reported. Extensive tickling experiments demonstrate that the cisoid coupling constants over four bonds are negative, while the corresponding transoid coupling constants are positive. Detailed results for the benzene solution, in which the non-equivalent protons of the —CH2Cl moiety have almost identical chemical shifts, show that although all the resonances may be unequivocally identified and measured to a high order of precision (± 0.03 Hz), an iterative computer fit (LAOCOON-3) has a larger uncertainty for the derived parameters than indicated by the "probable errors" furnished by the computer program. Analysis of the acetonitrile solution, however, furnishes a less ambiguous result. In addition, it is noted that use of relative apparent intensities of resonance peaks can lead to the wrong sign of those coupling constants whose magnitudes are near zero.
Preparation and some reactions of thiomethyl derivatives of aluminum
Authors: Lalancette J. M. , Beauregard Y. , Bhereur M.
Published: May 2006

The preparation of (CH3S)2AlCH3 and (CH3S)3Al from trimethylaluminum and methanethiol is reported. The reaction of CO2, COS, and CS2 with (CH3S)2AlCH3 yields (CH3S)3C—C(CH3S)3 and thiocarbonates respectively, besides dimethyl disulfide. With the same disubstituted aluminum derivative, phenylacetylene reacted to give C5H5C(SCH3)CH2. A study with deuterated phenylacetylene has permitted us to establish the mechanism of this reaction.
Kinetics of the pyrolysis of propylene. Part I
Authors: Simon M. , Back M. H.
Published: May 2006

not available
Mass spectral studies of metal chelates. V. Mass spectra and appearance potentials of some fluorine-substituted acetylacetonates
Authors: Reichert C. , Bancroft G. M. , Westmore J. B.
Published: May 2006

The mass spectra of the hexafluoroacetylacetonates (hfacac) and trifluoroacetylacetonates (tfacac) of Al(III), Cr(III), Fe(III), Fe(II), Cu(II), and Zn(II) are reported. The main features of the spectra are discussed. Compared with the spectra of the acetylacetonates (acac), substitution of CF3 for CH3 in these complexes leads to more extensive fragmentation of the molecular ions. For example, ions corresponding to loss of •CF3 radicals are more abundant than those corresponding to loss of •CH3 radicals. The appearance potentials (a.p.'s) of the molecular ions and, where possible, of fragment ions formed from the molecular ion by loss of •CF3, •CH3, or ligand radicals are reported. The a.p.'s of the molecular ions are more sensitive to the nature of the ligand than to the metal. Thus, for the metal chelates studied here the a.p.'s of the molecular ions from ML2 and ML3 (L stands for ligand) were 9.95 ± 0.25 V for L = hfacac, 9.05 ± 0.35 V for L = tfacac, and 8.3 ± 0.35 V for L = acac. The energy required to dissociate a •CF3 or •CH3 radical from the molecular ion is sensitive to the nature and valency of the metal M, being low (relatively) for Al(III) and Fe(III), and high (relatively) for Cr(III) (inferred) and Fe(II). This variation is discussed in terms of the effect of substituent, and of interaction of metal d orbitals with the ligands.
Synthesis of pinosylvin and related heartwood stilbenes
Authors: Bachelor F. W. , Loman A. A. , Snowdon L. R.
Published: May 2006

Pinosylvin dimethyl ether and three other stilbene ethers were prepared by condensing the appropriate diethylbenzylphosphonates with an aromatic aldehyde. Cleavage of pinosylvin dimethyl ether with boron tribromide gave in good yield the monomethyl ether, while fusion with pyridine hydrochloride yielded pinosylvin.
Thermochemistry of copper compounds: Cu(OH)2, CuCl2, Cu(IO3)2•H2O, and Cu(IO3)2
Authors: Gedansky L. M. , Pearce P. J. , Hepler L. G.
Published: May 2006

Calorimetric measurements have led to ΔHf0 values for solid Cu(OH)2, CuCl2, Cu(IO3)2•H2O, and Cu(IO3)2. These ΔHf0 values have been used with data from earlier investigations in evaluating ΔGf0 and S2980 values for these compounds. All of these quantities are based on "best" ΔGf0, ΔHf0, and [Formula: see text] values for Cu2+ (aq) derived in this paper.
The permeation of electrolytic hydrogen through lead
Authors: Čaderský Ivan , Muju Bansi L. , Smith Frank R.
Published: May 2006

Conclusive evidence is reported for the permeation of electrolytic hydrogen through lead. The diffusion coefficient at 25 °C lies between 10−7 and 10−6 cm2 s−1 while the bulk concentration of dissolved hydrogen is indicated to be 10−6 g-atom cm−3 at current densities of 10 to 50 mA cm−2.
Standard heats of formation of two tribromoborazines
Authors: Smith B. C. , Thakur Lambodar , Wassef (Mrs.) Marguerite A.
Published: May 2006

The heats of hydrolysis of B3Br3N3Me3 and B3Br3N3H3 are −84.4 ± 0.5 and −120.9 ± 0.5 kcal mole−1, and their standard heats of formation are −246.5 and −215.9 kcal mole−1, respectively. The estimated boron–nitrogen bond energy terms are 113.2 and 105.5 kcal mole−1, respectively.
Diagramme de phases du système K–K2O et le monooxyde de potassium K2O
Authors: Natola F. , Touzain Ph.
Published: May 2006

Le diagramme de fusion du système K–K2O est obtenu par la technique de l'analyse thermique différentielle. La fusion du monooxyde de potassium K2O se manifeste à 646 + 5 °C. Des transformations cristallines réversibles de l'oxyde sont observées à 317, 372 et 446 °C. La dismutation de l'oxyde en peroxyde et métal apparait à une température approximativement égale à celle de la dernière des transitions. Le diagramme K–K2O comporte un eutectique à une température très proche de la température de fusion du potassium et une monotectie à 600 °C (concentration monotectique: 30.5 % atomique d'oxygène). Aucune existence de sous-oxyde n'est démontrée.The potassium–oxygen phase diagram has been determined up to the composition of K2O by the technique of differential thermal analysis. Potassium monoxide K2O melts at 646 ± 5 °C. Reversible transitions occur in solid K2O at 317, 372, and 446 °C. Disproportion of the monoxide into the peroxide and metal occurs at a temperature identical or very near to that of the last transition. The K–K2O eutectic melts at a temperature very close to the melting temperature of pure K (degenerate eutectic) and the monotectic at 600 °C (monotectic concentration: 30.5 oxygen atomic %). No evidence has been obtained that would indicate the existence of a lower oxide.
Synthesis of 7-azabicyclo[2.2.1]heptane, exo-2-chloro-7-azabicyclo[2.2.1]heptane, and derivatives
Authors: Fraser Robert R. , Swingle Robert B.
Published: May 2006

A synthesis of 7-azabicyclo[2.2.1]heptane (1) in five steps and an overall yield of 18% has been achieved. An alternative five-step route which gives 1 in 36% yield but which requires large amounts of platinum oxide has also been developed. In comparison, the only previous synthesis of this compound gave less than a 1% overall yield of an impure product. Several N-acyl derivatives and the N-nitroso derivative have been prepared, and the barriers to rotation about the N—CO bond of the acetyl derivative and the N—NO bond of the nitroso derivative have been determined. The barriers were found to be 1.2 and 6.5 kcal less, respectively, than in their unstrained analogs. exo-2-Chloro-7-azabicyclo [2.2.1]heptane has also been synthesized.
Recombination of iodine atoms in sulfur dioxide
Authors: Brown J. , Burns G.
Published: May 2006

The reaction 2I + SO2 → I2 + SO2 has been studied between 293 and 668°K. At 293°K, the recombination rate constant is 2.6 × 1010]2 mole−2 s−1; it attains 1/10 of this value at 668°K. Although the infrared and ultraviolet spectra of SO2, studied previously, suggest the existence of two forms of SO2 in the temperature range in question, the present recombination studies present no further supporting evidence about the existence of the excited form.
Studies on some 1,2,4-dithiazolium salts
Authors: Ahmed M. , McKinnon D. M.
Published: May 2006

3-Alkylthio-1,2,4-dithiazolium salts are most conveniently made by alkylation of the corresponding 1,2,4-dithiazole-3-thiones by dimethyl sulfate. These salts readily undergo nucleophilic attack by amines in position 3, with loss of a methylthio group. Hydrogen peroxide oxidation, or chlorination, of the thiones gives the corresponding dithiazole-3-ones.
Ligand field splitting energies of the hexaamminecobalt(II) ion and the hexaamminenickel(II) ion measured by a calorimetric method
Authors: Muhammad Badri , Jamieson J. W. S.
Published: May 2006

Various normal lower ammines and high-energy modifications of the lower ammines of cobalt(II) sulfate and nickel(II) sulfate have been prepared and the heats of solution in dilute ammonia have been measured for both types. For each of these ammine systems the maximum difference in heat of solution, expressed as kcal/mole of each heptaammine, between the high-energy and the normal salts has been found to be in close agreement with the ligand field splitting energy of the hexaamminemetal(II) ion.
Studies of the pore structures of silica gels by electron microscopy and low-temperature nitrogen adsorption
Authors: Robinson E. , Ross R. A.
Published: May 2006

The pore structures of a number of silica gels have been examined by low-temperature (−196 °C) nitrogen adsorption isotherms and these data compared with information obtained from electron photomicrographs. Good general agreement was obtained in the comparison, although the electron photomicrographs reveal more details regarding pore arrangements and dimensional variations. Gel structures were modified by heating and also by treatments with superheated steam or nitric acid. The aggregation of ultimate particles is affected by the steam treatment and this phenomena is compared with the preliminary stages of accepted sintering mechanisms.
Pyoluteorin, a synthesis
Authors: Bailey K. , Rees A. H.
Published: May 2006

The synthesis of Pyoluteorin, an antibiotic from Pseudomonasaeruginosa is described. The method used produced in addition, an isomer 3,5-dichloro-2-(2′,6′-dihydroxybenzoyl)pyrrole, for which the name isopyoluteorin is proposed. The bromine analogue of pyoluteorin is also reported.
Reactions of the U(VI) complexes of oxine
Authors: Corsini A. , Abraham J.
Published: May 2006

The interaction of the oxine adduct, UO2(C9H6NO)2•C9H6NOH, and of the bis compound, UO2(C6H6NO)2, with several solvents has been studied. The oxine ligand in the adduct is displaced by DMSO but the adduct is stable in solvents of relatively low polarity. The bis compound is unstable and reacts to form both the adduct and solvates. Under appropriate conditions, the addition reaction between the bis compound and a solution of oxine is quantitative. Studies with [14C]-oxine revealed that the addition is accompanied by two exchange reactions.
Reductions with sulfurated borohydrides. V. Reductions of ketones
Authors: Lalancette J. M. , Freche A.
Published: May 2006

Ketones can be reduced with sulfurated sodium borohydride. Very high yield (≈90%) of the corresponding alcohol is obtained with the appropriate ratio of ketone and hydride at room temperature. The reaction is much influenced by the steric environment around the carbonyl group. At high temperature (65°) disulfides and tetrasulfides are produced. In some cases the structure of those sulfides have been established. Conjugated ketones can be reduced to the corresponding alcohols with very high yields.
Some problems affecting the determination by gas–liquid chromatography of vanillin and syringaldehyde in oxidized neutral sulfite pulping liquors
Authors: Harrington K. J. , Hamilton Janet
Published: May 2006

Gas–liquid chromatographic parameters for the quantitative evaluation of syringaldehyde and vanillin in oxidized neutral sulfite pulping liquors are discussed.
Vibrational spectra and proposed crystal structure of some tetraphenylarsonium compounds
Authors: Walford L. K. , Blattner Richard J. , Feldman Stephen , Bain R. L.
Published: May 2006

The crystal structures of (C6H5)4AsBF4, (C6H5)4AsPF6, (C6H5)4AsAsF6, and (C6H5)4AsSbF6 have been studied by X-ray diffraction. The unit cells are all tetragonal. The fluoroborate compound is probably isostructural with (C6H5)4AsFeCl4. The other three compounds are almost isostructural with (C6H5)4AsFeCl4, the only change being the accommodation of the dipyramidal PF6− ion in the space group [Formula: see text] (No. 82). Infrared absorption spectra are in general agreement with previous work on tetraphenylarsonium halides and compounds with hexafluoro Group VA ions. It is concluded that crystal field effects for this series of salts do not markedly affect the vibrational spectra.
Electron spin resonance studies of methyl radicals stabilized on porous VYCOR glass: various surface interactions, second-order splitting, and a linewidth temperature study
Authors: Garbutt G. B. , Gesser H. D.
Published: May 2006

Electron spin resonance studies have been performed on methyl radicals stabilized on the surface of porous VYCOR glass. As previously reported, two very different methyl radicals, denoted Me and Me′, were seen. Results indicate that the radical Me′ is most probably weakly bound to the boroxane group (=B—O—B=) which is prominent on the surface of high temperature (700–900 °C) pretreated porous VYCOR glass. Four satellite lines about each Me line, denoted previously as radical X, were observed when the surface was pretreated at lower temperatures (400–500 °C). In an earlier publication radical X was attributed to the interaction between methyl radicals and the isotopic surface species 11B. In this study two additional satellite lines about each Me line are reported as well as a reassignment of the origin of all satellite lines. Four of the six satellite lines have been assigned to forbidden "spin–flip" transitions while the other two have been assigned to direct interaction between methyl radicals and the surface hydroxyl protons. Support for the irreversibility of high temperature dehydroxylation of porous VYCOR glass is also presented.A partial resolution of the second-order splitting of each of the central pair of lines was achieved for the normal methyl radical. The value of the second-order splitting was between 220 and 230 mG. The linewidths of the two central lines were measured at 77 °K. The samples were then allowed to warm up to various temperatures and then recooled to 77 °K. The linewidths were smaller after completing this cycle. Storage of the sample at 77 °K allowed the linewidths to return to their original values. These linewidths effects are explained by postulating the existence of two different types of potential wells on the surface.
The preparation and vibrational spectra of some phenylchlorostannates
Authors: Wharf I. , Lobos J. Z. , Onyszchuk M.
Published: May 2006

The preparations of tetra-alkylammonium salts of the [(C6H5)2SnCl3]−, [(C6H5)2SnCl4]2−, and [(C6H5)3SnCl2]− ions are described. Infrared spectra (1300–100 cm−1) and Raman (400–100 cm−1) spectra are reported and an assignment of the bands is made.
The mass spectrum of exo-2-norbornyl chloride; the elucidation of the fragmentation mechanism and ion structures by metastable ion analysis
Authors: Holmes J. L. , McGillivray D. , Isaacs N. S.
Published: May 2006

The mass spectra of exo-2-norbornyl chloride and several deuterated analogues have been examined in detail with particular regard to metastable peaks involving the molecular ions and norbornyl cations. The molecular ion does not undergo Wagner–Meerwein isomerization prior to fragmentation; in the norbornyl cation the hydrogen atoms have lost their identity as shown by random H and D loss when the ion ejects an ethylene molecule. Metastable ion analysis is proposed as a method for studying the participation of norbornyl carbonium ions in the preparation of 2-norbornyl chloride.
Cyanoethylations and Michael additions. II. The synthesis of allylic cyclohexenols by γ-cyanoethylation of α,β-unsaturated aldehydes and ketones. Part II
Authors: Engel Ch. R. , Lessard J.
Published: May 2006

The detailed report of the first cyclo-γ-cyanoethylation of an α,β-unsaturated carbonyl system, 3β-acetoxy-5α-pregn-17-en-21-al, is given. This reaction, which proceeds in high yields, gives rise, in a single operation, to products with an additional functionalized six-membered ring, primarily to allylic α′-cyanohexenols.
Vibrational and Mössbauer spectra of some hexachloro- and hexafluorostannate complexes
Authors: Carter H. A. , Qureshi A. M. , Sams J. R. , Aubke F.
Published: May 2006

119Sn Mössbauer and vibrational spectra for a number of SnF62− and SnCl62− complexes have been obtained. One fundamental for the SnF62− ion has been reassigned. Strong evidence for anion–cation interaction for (ClO2)2SnF6 is obtained both from the vibrational spectra and from the Mössbauer spectra where a non-zero quadrupole splitting is found.
Reinvestigation of the nature of the reactive intermediate in electrophilic bromine addition to styrenes
Authors: Pincock James A. , Yates Keith
Published: May 2006

The rate constants for the electrophilic addition of bromine to a series of ring-substituted styrenes have been redetermined. The new ρ+ value of −4.71 is discussed in terms of the intermediate involved for these substrates.
Studies of fluoroberyllate complexes in aqueous solution by I9F nuclear magnetic resonance
Authors: Hogben M. G. , Radley K. , Reeves L. W.
Published: May 2006

Studies of aqueous solutions containing fluoride and beryllium ion in ratios between 5 and 0.5 were made by 19F nuclear magnetic resonance at temperatures between the melting point of solutions and room temperature. Signals clearly identifiable as arising from BeF42−, BeF3−, BeF2, and BeF+ were assigned. Chemical shifts and coupling constants JBe–F are reported for all species and approximate equilibrium constants are determined from intensity measurements for the reactions [Formula: see text] [Formula: see text] and [Formula: see text]
The mercury-(3P1)-photosensitized decomposition of formamide vapor
Authors: Boden J. C. , Back R. A.
Published: May 2006

The mercury-(3P1)-photosensitized decomposition of formamide vapor has been studied briefly at 150 °C and pressures of about 1–30 Torr. Volatile products observed were CO, H2, and NH3. Three primary processes are postulated[Formula: see text]with estimated quantum yields of 0.53, 0.32, and 0.08, respectively. A dependence of product ratios on light intensity and formamide pressure is attributed to hydrogen-atom "cracking" reactions.
The dielectric properties of 1,1-dichlorocyclohexane in a supercooled region
Authors: Chan R. K. , Clayton W. L.
Published: May 2006

From dielectric constant measurements of supercooled 1,1-dichlorocyclohexane in the anomalous dispersion region, the free energy, entropy, and enthalpy of activation for dielectric relaxation are found to be 4.05 kcal mole−1, 123 cal °K−1 mole−1, and 22.3 kcal mole−1, respectively, at −125 °C. The calculated maximum free energy barrier of crystal nucleus formation based on simple nucleation theory is 3.64 kcal mole−1. In view of the qualitative agreement between the experimental free energy of activation of dielectric relaxation and the calculated free energy of activation of nucleation, it is reasonable to conclude that the processes of molecular orientation and of crystal nucleus growth are similar. A calculation of the free energy barrier vs. crystal nucleus size diagram also predicts spontaneous crystallization when the radius of crystal nuclei exceeds 12.8 Å.
The low frequency infrared and Raman spectroscopic studies of some uranyl complexes: the deformation frequency of the uranyl ion
Authors: Bullock J. I. , Parrett F. W.
Published: May 2006

A study of the low frequency vibrational spectra of compounds of the type L2UO2(NO3)2 (L = mono-dentate ligand), MUO2(NO3)3 (M = monovalent cation), and CS2UO2X4 (X = Cl or Br) has shown that the deformation frequency of the uranyl group occurs in the region 274–245 cm−1 but detailed assignments of the U—O (nitrate) frequencies are not given since it is shown that structurally related complexes do not necessarily give similar low frequency infrared (i.r.) and Raman spectra.
Synthesis of p-O-(tetra-O-acetyl-α-D-glucopyranosyl)-penicillin G
Authors: Nagabhushan T. L. , Chin C. G.
Published: May 2006

The synthesis of p-O-(tetra-O-acetyl-α-D-glucopyranosyl)-phenylacetic acid from tetra-O-acetyl-2-deoxy-2-nitroso-α-D-glucopyranosyl chloride and t-butyl-p-hydroxyphenylacetate and its coupling with 6-aminopenicillanic acid by way of the corresponding acid chloride to give p-O-(tetra-O-acetyl-α-D-glucopyranosyl)-penicillin G is described.
Effect of pH on the reaction of 1,3-dihydro-1-hydroxy-3-oxo-1,2-benziodoxole with 2-mercaptoethanol, 2-mercaptoethylamine, and glutathione
Authors: Leslie James
Published: May 2006

The kinetics of the oxidation of 2-mercaptoethanol, 2-mercaptoethylamine, and glutathione with 1,3-dihydro-1-hydroxy-3-oxo-1,2-benziodoxole (1) have been examined at pH 4–5.6. The reaction is second-order, which can be explained by a rate-determining step involving the reaction of one molecule of the thiol with one molecule of 1. The second-order rate constants vary in a linear manner with the reciprocal of the hydrogen ion activity. The ionic species involved in the reaction are discussed.
Structure of thallium amalgams and their reaction with oxygen
Authors: Foley W. T. , Nemori Masaaki , MacNeil James D.
Published: May 2006

The stoichiometry was determined for the oxide formed by bubbling oxygen through thallium amalgam until the wt.% thallium in the amalgam was reduced by about 2%. The composition of the oxide depended upon the wt.% Tl in the amalgam. In the most dilute amalgams the oxide approached the formula Tl2O and as the wt.% Tl increased the oxide became richer in thallium(III). Between 20 and 29 wt.% Tl the oxide approximated Tl3O2 and for alloys richer in thallium the oxide became richer in thallium(III). When the wt.% Tl in the alloy was 41.0 the ratio of thallium to oxygen in the oxide was 1.19. It is suggested that the experimental results indicate the existence of shortrange order in the liquid.
Systèmes métaux alcalins–oxygène. 3ème Partie. Polymorphisme du monooxyde de potassium K2O
Authors: Touzain Ph. , Brisse F. , Caillet M.
Published: May 2006

First order reversible transitions occur in potassium monoxide successively at 317 and 372 °C. These transitions have been observed by differential thermal analysis. The known form is γ-K2O, face-centered cubic, a = 6.436 Å. The new forms are β-K2O between 317 and 372 °C, primitive cubic, a = 12.125 Å and α-K2O from 372 °C to the melting point, rhombohedral, a = 12.543 Å, α = 91.47°. An order–disorder transformation occurs at 446 °C. It is at approximately this temperature that K2O begins to disproportionate into K2O2 and K.
Detection of the intermediate in the aqueous acid catalyzed isomerization of cis-cinnamic acid
Authors: Hocking M. B.
Published: May 2006

The rates of isomerization of cis-cinnamic acid and of dehydration of β-hydroxy-β-phenylpropionic acid have been determined in strong HCl solutions. The ratio kdehydration/kisomerization was found to be in the range 1.6 to 4 and has been used to account for the observed lengthy isomerization induction periods. Concentrations of a previously suggested intermediate, 5, assuming its presence, have been calculated. Accounting for the concentration of intermediate present has enabled mathematical and experimental removal of the induction period from the kinetics. Attempted isolation of this intermediate resulted at least in positive detection of its presence.
Radiolysis of gaseous isobutene by 60Co γ-rays. III. Low boiling point condensation products
Authors: Herman Jan A.
Published: May 2006

During the γ-rays irradiation of gaseous isobutene the following low boiling point condensation products are formed: 2-methyl-1-butene, 2-methyl-2-butene, 1,1-dimethyl-cyclopropane, 3-methyl-1-butene, neopentane, isopentane, and n-pentane. All these products are formed in radical processes, as shown by the scavenging action of nitric oxide. The formation of the pentenes results from the reaction of the methylene radical with isobutene, whereas the reaction of the methyl radical with the monomer accounts for the production of pentanes.
Chemistry of 2-substituted adamantanes. I. Adamantanethione, its dimer and trimer
Authors: Greidanus J. W.
Published: May 2006

The preparation of adamantanethione from adamantanone is reported, either via 2-ethoxy-2-adamantanethiol or directly with the aid of phosphorus pentasulfide. The conditions for the latter reaction were developed so as to give the highest yield (91%). Dimerization or trimerization of the thioketone under the influence of methanesulfonic acid leads to dispiro[1,3-dithietane-2.2′:4.2″-diadamantane], resp. trispiro[1,3,5-trithiane-2.2′:4.2″:6.2″′-triadamantane]. The spectral properties of the compounds are discussed, especially the n.m.r. spectrum of the thione in connection with the anisotropy of the thiocarbonyl group, and the aromatic solvent-induced shift.
Surface tensions of binary liquid systems. I. Mixtures of nonelectrolytes
Authors: Lam V. T. , Benson G. C.
Published: May 2006

Surface tensions were measured for the ten binary liquid systems: cyclopentane + carbon tetrachloride, cyclopentane + tetrachloroethylene, cyclopentane + benzene, cyclopentane + toluene, cyclohexane + tetrachloroethylene, cyclohexane + benzene, cyclohexane + toluene, cyclohexane + cis-decalin, cyclohexane + trans-decalin, and benzene + o-xylene. The system cyclohexane + benzene was studied at 20 and 30 °C. Measurements for the other nine systems were carried out at 25 °C. The principle of corresponding states was used to correlate the surface tension results with other properties of the pure component liquids and of their binary mixtures.
Ethylene exchange in PtCl(C5H7O2)(π-C2H4)
Authors: Holloway C. E. , Fogelman J.
Published: May 2006

The kinetics of exchange of free with complexed ethylene in the system PtCl(acac)(π-C2H4) have been investigated over a temperature and concentration range by proton magnetic resonance. First order kinetics are observed with respect to each component with no solvent dependence of rate. The activation energy and entropy are 2.7 kcal mole−1 and −36 cal deg−1 mole−1, respectively. A five coordinate intermediate is suggested, with complete retention of configuration at the platinum.
Some observations on isotopic scramblings accompanying acetolysis in the 2-norbornyl system
Authors: Lee C. C. , Hahn Bo-Sup , Lam L. K. M. , Woodcock D. J.
Published: May 2006

Evidence is presented to show that in the acetolysis of isotopically labeled exo- or endo-2-norbornyl brosylate (exo- or endo-1-OBs) in NaOAc buffered HOAc, the initially formed product, exo-1-OAc, could undergo further isotopic scrambling during its subsequent contact with the reaction medium. These scramblings in the acetate apparently involved relatively large amounts of rearrangement of the label from C-2 to -3. After partial acetolysis of exo- or endo-1-OBs-2-d, n.m.r. analysis showed that the recovered endo-brosylate was unchanged, while the D-label in the recovered exo-brosylate has definitely rearranged from C-2 to -1 and probably also to C-6. Thus, in the acetolysis of labeled exo-1-OBs as commonly carried out in HOAc–NaOAc, isotopic scramblings could occur not only in the solvolysis reaction itself, but also prior to the reaction due to internal return giving rise to scrambled brosylate and subsequent to the reaction due to further scrambling in the initial product. Other mechanistic implications of the results are also discussed.
Temperature Dependence of the Diffusion of Carbon Tetrachloride, Chloroform, and Methylene Chloride Vapors in Air by a Rate of Evaporation Method
Authors: Watts Harry
Published: May 2006

The diffusion coefficients in air of carbon tetrachloride, chloroform, and methylene chloride have been measured over a temperature range from room temperature to close to their boiling points by a modified rate of evaporation method. It was shown that considerable error can occur in diffusion coefficients determined by the rate of evaporation method when gas imperfections are ignored.
Spin–Spin Coupling Constants Between Protons and Carbon in 1,3-Dithiole-2-thione and 1,3-Dithiole-2-one. Relationship of cisoid H–H to Two-bond 13C–H Couplings in Ethylene Derivatives and Aromatic Compounds
Authors: Mckinnon D. M. , Schaefer T.
Published: May 2006

Precise analyses of the p.m.r. spectra of 1,3-dithiole-2-thione and 1,3-dithiole-2-one containing 13C at positions 4 and 2 yield all proton–proton and proton–carbon spin–spin coupling constants. The two-bond proton–carbon couplings are discussed relative to directly bonded proton–carbon couplings in terms of hyperconjugative effects and it is suggested that d orbital participation in sulfur bonding is unimportant in these compounds. A linear correlation of two-bond proton–carbon with cisoid proton–proton couplings in some ethylene derivatives and aromatic compounds indicates that the above two compounds behave like ethylene derivatives in this respect, in contrast to benzene, furan, and thiophene. Practical use of the correlation in the analysis of complex 13C resonance spectra is indicated.
Pyrazolines XI. Determination of the Stereochemical Changes at Carbons-3 and -5 of 1-Pyrazolines on Their Thermal Conversion to Cyclopropanes
Authors: Mcgreer D. E. , Mckinley J. W.
Published: May 2006

Six 3,3,4,5-tetrasubstituted pyrazolines have been prepared and the product distribution from their pyrolysis reactions have been determined. This has permitted for the first time the unambiguous evaluation of the stereochemical fate of C-3 and -5 of the pyrazolines on conversion to cyclopropanes. A stereoselectivity is noted for these systems which can be related to the structure of the initial pyrazoline. This suggests that the transition state for reaction retains many of the stereochemical factors present in the pyrazoline. Such a condition would be the case for concerted breaking of the two C—N bonds with a developing overlap of the new bonds being formed at the transition state. That this reaction is not restricted by symmetry constraints suggests that the three carbon fragment can act as a symmetric or antisymmetric unit and that these are not separated by more than a few kcal of energy.
Reaction of Methyl-lithium with Phosphonitrilic Fluorides: a Novel Orientation Pattern
Authors: Paddock N. L. , Ranganathan T. N. , Todd S. M.
Published: May 2006

The reaction of methyl-lithium with the phosphonitrilic fluorides (NPF2)3–5 follows a predominantly geminal course, the third and fourth substituents in the tetrameric ring entering antipodally to the first two. This behavior, and the competitive occurrence of an addition reaction, is attributed to the π-inductive effect of the substituents on a delocalized homomorphic π-system.
Dimethylgermanium Dinitrate
Authors: Potts D. , Walker A.
Published: May 2006

Dimethylgermanium dinitrate has been prepared by the reaction of dimethylgermanium dichloride and nitrogen pentoxide in carbon tetrachloride. The properties of this compound have been investigated and compared with those of other known Group IVA alkyl nitrates. The vibrational spectra show that the nitrato groups are covalently bound to the germanium in a unidentate manner. Ultraviolet spectra and conductivity measurements indicate that the compound behaves as a 1:2 electrolyte in water and dimethyl sulfoxide but is a non-electrolyte in methyl cyanide, nitromethane, and ethyl acetate. The complexes Me2Ge(NO3)2•py and Me2Ge(NO3)2•2,2′dipy have been prepared and the infrared spectra of these compounds indicate considerable weakening of the germanium-nitrato bonds.
Reactions of Benzylamine with Sulfur
Authors: Sasaki Yukihiko , Olsen Fredric P.
Published: May 2006

A five-step sequence has been established for the room temperature reaction of sulfur with benzylamine. Benzylamine polysulfides and benzylidenimine polysulfides occur as interconverting intermediates in this system. The final products are benzylammonium polysulfides, ammonia, and N-benzylidene benzylamine.
Electron Spin Resonance Study of Surface Defects of Silica Gel Formed by Gas Discharges
Authors: Hukuda K. , Amenomiya Y.
Published: May 2006

Surface defects of silica gel formed by a microwave electric discharge in a stream of oxygen and of nitrogen have been studied by means of electron spin resonance (e.s.r.) spectroscopy. The magnetic center is identified as a hole trapped by a surface oxygen atom which is formed by the removal of a hydrogen atom from a hydroxyl group. The principal values of the g-tensor were found to be gxx = 2.037, gyy = 2.008, and gzz = 2.002, respectively, where the direction of x-axis was taken along the O—Si bond. The center has a weak hyperfine interaction with a hydrogen nucleus of an adjacent hydroxyl group. The hyperfine splitting is 15 Oe.
Free Radicals by Mass Spectrometry. XLIII. Ionization Potentials and Ionic Heats of Formation for Vinyl, Allyl, and Benzyl Radicals
Authors: Lossing F. P.
Published: May 2006

Using an energy-resolved electron beam, ionization potentials for the following free radicals have been measured: vinyl 8.95 V, allyl 8.07 V, benzyl 7.27 V. For vinyl and allyl ions new measurements of thresholds for dissociative ionization give ΔHf(C2H3+) = 266 kcal/mol and ΔHf(C3H5+) = 226 kcal/mol, leading to neutral radical heats of formation ΔHf(C2H3) = 59.6 kcal/mol and ΔHf(C3H5) = 40 kcal/mol. The data for benzyl radical and ion give ΔHf(benzyl cation) = 213 kcal/mol.
The Crystal Structure of KIO3.HIO3
Authors: Chan Lilian Y. Y. , Einstein F. W. B.
Published: May 2006

The crystal structure of potassium hydrogen di-iodate (bi-iodate) KIO3.HIO3 was determined from three dimensional X-ray data collected by counter methods. The structure was refined by full-matrix least-squares techniques to a conventional R factor of 5.0 % for the 1392 observed reflexions. The salt crystallizes in the monoclinic space group P21/c with eight formula units in a cell of dimension a = 7.028(1) Å, b = 8.203(1) Å, c = 21.841(3) Å, β = 98.03(1)°.The iodate units are all basically pyramidal; weak interionic I—O contacts complete a very distorted octahedral environment around three iodine atoms. There is a capped octahedral (7-coordinate) environment around the remaining iodine atom. The I—O bonds are in the range 1.75–1.82 Å and the I—OH bonds are 1.91 and 1.95 Å, variations in length can be correlated with differences in the degree of involvement in (a) hydrogen bonding and (b) interaction with adjacent iodine atoms.
Benzo[b]phosphole and Derivatives
Authors: Chan T. H. , Wong L. T. L.
Published: May 2006

A potentially general synthesis of 1-heteroindene has been developed and applied to the preparation of l-phenylbenzo[b]phosphole, a novel heterocyclic system.
Kinetics of the Mercury-Photosensitized Decomposition of Propane. Part I. The Overall Mechanism
Authors: Papic M. M. , Laidler K. J.
Published: May 2006

The mercury-photosensitized decomposition of propane was investigated from 250 to 350 °C, and at pressures from 5 to 700 Torr. The following products were identified and their initial rates of formation measured: H2, CH4, C2H4, C2H6 (CH3)2CHCH(CH3)2, (CH3)2CHCH2CH2CH3, and n-C6H14. The results lead to conclusions about the mechanism. The pressure dependence of the rates were determined and interpreted in terms of a simplified steady-state treatment based on the mechanism.
Mechanism of Oxidative Decarboxylation of α-Hydroxy Acids by Bromine Water. Part II. Oxidation in Acidic Medium. A Comparison with the HOBr – Oxalic Acid Reaction
Authors: Pink Judith M. , Stewart Ross
Published: May 2006

The oxidative pattern of α-hydroxy acids by acidic bromine water is shown to be similar to the oxalic acid – bromine water reaction. In both cases HOBr is the oxidant and the undissociated form of the organic acid is required for reaction to occur. The rate law −d[HOBr]/dt = k[HOBr][hydroxy acid] is observed for oxidations carried out in the presence of Ag+ ion in the pH range 2–5. Below that pH bromination occurs. Bell-shaped pH-rate profiles are obtained for the oxidations of benzilic, mandelic, and 2-hydroxy-2-methylpropanoic acids. The calculated rates, based on a steady state treatment of a reaction path involving a hypobromite intermediate (R2COBrCO2H) are in agreement with the observed values and with the observation that the rates of oxidation of mandelic acid in D2O and H2O are the same.
A Facile Formation of Dibenzo [a,d] cycloheptenylium Ion by Decarbonylation. Color Reactions of the Cyheptamide Metabolites
Authors: Sestanj K.
Published: May 2006

Treatment with concentrated sulfuric acid of different 10-hydroxylated metabolites of the anticonvulsant cyheptamide results in intensely colored products. These have been identified as dibenzo-[a,d]cycloheptenylium ions.
Nuclear Magnetic Resonance Studies of Molecular Motion in a Number of Stearates and Oleates
Authors: Ripmeester J. A. , Dunell B. A.
Published: May 2006

The broad line p.m.r. spectra of the alkali metal oleates have been observed from 77 °K up to or beyond the crystalline to waxy phase transition. Lower phase transition temperatures are observed in the oleates than in the stearates. This fact is attributed to larger entropies of transition in the oleates than in the stearates. The n.m.r. second moments indicate that in the stearates the packing of chains is probably not closer than in the oleates and consequently that the barriers to chain reorientation are not significantly higher in the stearates than in the oleates. Sodium oleate and stearate both appear to behave irregularly in the series of alkali metal soaps. Spin-lattice relaxation times have been measured by adiabatic rapid passage methods for both alkali metal oleates and stearates. Values of T1 and of the activation energy barrier for the reorientation of end methyl groups are compared with values obtained by other workers. No significant difference is seen between relaxation processes in stearates and oleates, at least in the lower temperature range. Soaps which seem to have some amorphous character have a second relaxation mechanism, in addition to end methyl group rotation, which is evidently important in the region of about 150–250 °K.
Effect of Substituents on the Chemical Shift of Benzylic Protons. III
Authors: Fraser Robert R. , Renaud Roger N.
Published: May 2006

The effects of para substituents on the chemical shifts of the diastereotopic benzylic protons in three series of chiral molecules have been determined from a study of the 100 MHz spectra of these molecules in deuterochloroform. The results show that the slope, ρ, obtained from a plot of τ vs. Hammett σ constant, is influenced by a number of factors and that the conformational disposition of the benzylic proton with respect to the aromatic ring is not a dominant factor.
Synthesis of 1H-Benzo[d,e-1,7]naphthyridines, a Novel Heterocyclic Ring System
Authors: Humber L. G.
Published: May 2006

A simple six-step synthesis, from homoveratrylamine, of 5,6-dimethoxy-2,3,7,8,9,9a-hexahydro-1-(p-toluenesulfonyl)-1H-benzo[d,e-1,7]naphthyridine, the first representative of a novel heterocyclic ring system, is described. Various transformation products and derivatives of the ring-system are also recorded.
Bromination of Norbornene: the Question of Bromonium Ions vs. 6,1-Hydride Shift
Authors: Marshall D. R. , Reynolds-Warnhoff P. , Warnhoff E. W. , Robinson J. R.
Published: May 2006

The reaction of norbornene (1) with bromine has been re-investigated and found to give in addition to bromonortricyclene (2) and 2-exo-bromonorbornane (20) a complex mixture of dibromides of which five (15–19) have been isolated and identified. These dibromides have been found to be kinetically controlled products of ionic addition. Apparently dibromide 15 is also formed to some extent in carbon tetrachloride by a radical mechanism. The product composition from the bromine addition has been compared with that of the analogous chlorination and bromofluorination reactions. Degradation of the 2-exo,3-endo-dibromonorbornane from bromination of 5,6-14C-norbornene has shown that this dibromide is formed by two ionic routes: (a) from a bromonium ion 14 (or its equivalent), and (b) from the cation 12 formed by 6,1-hydride shift. Improvements have been made in the first and final steps of the standard norbornene degradation method.
The Gas-Phase Acidity Order of Some Inorganic Acids
Authors: Young L. Brewster , Lee-Ruff E. , Bohme D. K.
Published: May 2006

The gas-phase acidity order at 300 °K of the inorganic acids, water, ammonia, and hydrogen has been directly determined using the flowing afterglow technique. The order established is H2O > H2 > NH3, water being the strongest acid in this series. This result is inconsistent with recent calculations, current available thermochemical data, and the order found in solution.
Behavior of Extra Electrons in the Liquids Methane, Ethane, and Propane
Authors: Robinson M. G. , Fuochi P. G. , Freeman G. R.
Published: May 2006

The radiation induced electrical conductances of liquids methane, ethane, and propane have been measured. At a field strength of 5 kV/cm the number of ion pairs collected at the electrodes per 100 eV absorbed by the liquid was 1.5 in methane (−160°), 0.20 in ethane (−90°), and 0.14 in propane (−90°). The short-lived conductance transient (k/u overshoot) observed at low field strengths in methane was 40% as large as that in argon. No transient was observable in ethane or propane. The freeness of motion of electrons in liquid methane is nearly as great as that in liquid argon and much greater than that in ethane or propane.