bluuebunny/crossref_metadata_2025 huggingface dataset:
Coordination compounds of olefins with anhydrous silver salts. IV. Complexes with some endocyclic monoolefins
Authors: Quinn H. W. , VanGilder R. L.
Published: May 2006

A study has been made of the changes in the infrared and nuclear magnetic resonance (n.m.r.) spectra of cyclopentene, cyclohexene, cycloheptene, and cis-cyclooctene, and of their 1-methyl-substituted analogues upon formation of the silver tetrafluoroborate complexes, AgBF4•2olefin. Based on the perturbation of the double bond stretching frequency in the olefin, the order of decreasing strength of the silver ion – olefin interaction is cyclopentene > cyclohexene > cis-cyclooctene ≈ cycloheptene.
Spectrofluorometric studies. VI. Photochemistry of toluene vapor excited in the 2480–2660 Å region
Authors: Lem S. L. , Semeluk G. P. , Unger I.
Published: May 2006

The fluorescent yields and triplet yields of toluene vapor as a function of exciting wavelengths and pressure have been determined. The sensitized emission of biacetyl technique was used to determine triplet yields. The sums of fluorescent yield and triplet yield at 2660, 2600, and 2540 Å are near unity. The data reported here confirm recently published results on toluene wherein the cis–trans isomerization of olefins technique was used as a triplet probe.
A Mössbauer study of adducts of triphenyltin chloride with oxygen-donor substances
Authors: Wedd R. W. J. , Sams J. R.
Published: May 2006

Mössbauer parameters for triphenyltin chloride and a number of its adducts with oxygen-donating Lewis bases are reported. The isomer shifts for all the compounds reported are constant within experimental error (1.29 ± 0.03 mm s−1, relative to SnO2). An approximate correlation between quadrupole splitting and the shift in element–oxygen stretching frequency between neat and complexed base is noted. This suggests that in general for these adducts, larger quadrupole splittings are associated with stronger complexes.
Photochemical synthesis 29. Photoannelation and cyclohexenone
Authors: Mayo P. De. , Nicholson A. A. , Tchir M. F.
Published: May 2006

Values of 1.7 × 108 s−1 and 2.5 × 107 M−1 s−1 for kd, the unimolecular rate constant for decay, and kr, the rate constant for addition to cyclohexene, have been obtained for cyclohexenone. These indicate that this cyclenone decays somewhat faster and reacts significantly slower with the same substrate (in the same solvent) than does cyclopentenone. Evidence is adduced, from sensitization experiments and the phosphorescence quenching of a range of carbonyl compounds, that the reactive triplet and lowest triplet of cyclohexenone lie close together, if they are indeed not identical, and the energy of this triplet is in the region of 66–68 kcal/mole. This is higher than that indicated by photostationary state measurements. This latter method, applied to cyclenones, may be suspect, and triplet energies so derived subject to doubt (that of cyclopentenone included) or have a different significance from those obtained by other methods. Further attempts to demonstrate the existence of a lower, cycloadditively unreactive, triplet in cyclopentenone have been negative. It now seems far more likely that the original interpretation was in error, that the lowest energy triplet is near 73 kcal/mole, and that a special mechanism for quenching benzophenone triplets by ground state cyclopentenone exists. The evidence for other multiple reactive triplets is re-examined as is the evidence for the nature of the states involved.
60Co γ-radiolysis of oxygenated aqueous solutions of cysteine at pH 7
Authors: Packer J. E. , Winchester R. V.
Published: May 2006

In the radiolysis of oxygenated aqueous solutions of cysteine (RSH) at pH 7, short chain reactions occur yielding cystine (RSSR) and hydrogen peroxide. Two competing reaction paths involving reaction of the thiyl radical (RS•) with oxygen or thiol anion (RS−) are postulated to explain the results.
Electron spin resonance study of γ-irradiated dipotassium difluoromalonate monohydrate
Authors: Herring F. G. , Lin W. C. , Mustafa M. R.
Published: May 2006

The γ-irradiation of dipotassium difluoromalonate monohydrate led to the formation of two molecular configurations of the ĊF2CO2− radical in addition to the previously identified ĊF(CO2−)2 radical. A comparison of the α-fluorine coupling in the two forms of the ĊF2CO2− radical indicates that loss of a carboxylate group nearly coplanar with the C—C—C plane in the undamaged molecule is favored.
Thermolysis of some 2,3-diazabicyclo[3.3.0]octene systems
Authors: Schneider Manfred P. , Crawford Robert J.
Published: May 2006

The kinetics and products of thermolysis of 2,3-diazabicyclo[3.3.0]oct-2-ene (1), 2,3-diazabicyclo-[3.3.0]octa-2,7-diene (2), and exo-4-methyl-2,3-diazabicyclo[3.3.0]octa-2,7-diene (3) are described and compared with previously studied pyrazolines. The secondary kinetic isotope effects of 1-d2 and 2-d2 have been measured. The synthesis and nuclear magnetic resonance spectra of these compounds and their thermolysis products are discussed.
Vibrational spectra of some isonitrile complexes of cobalt(I) and (II)
Authors: Boorman P. M. , Craig P. J. , Swaddle T. W.
Published: May 2006

The Raman and low-frequency infrared spectra of the trigonal-bipyramidal complexes Co(RNC)5ClO4(R = Me, Et, Ph) have been recorded and assigned. It is found that δ(CoCN) modes occur at higher frequencies than ν(Co—CN) modes. Although Raman spectra of the blue and yellow forms of Co(PhNC)5(ClO4)2 could not be obtained, the low-frequency infrared spectra are consistent with the C4v structure previously suggested (1). The dimeric complexes Co2(RNC)10(ClO4)4 (R = Me, Et) have been studied, and tentative assignments of the Raman and infrared spectra made on the basis of D4d symmetry. Spectra of the complexes Co2(RNC)10I(ClO4)3 (R = Me, Et) strongly support the previously suggested structural formulation (2) [(MeNC)5Co—I—Co(MeNC)5](ClO4)3, and furthermore indicate that the Co—I—Co skeleton is linear.
Solvent effects in the Cope rearrangement
Authors: Wigfield Donald C. , Feiner Steve
Published: May 2006

Mechanistic ambiguity in the kinetic results of certain Cope rearrangements has been resolved. It is concluded from rate studies in solvents of widely differing polarity that there is negligible contribution of an ionic mechanism, even in rearrangements of substrates structurally best suited to this mechanism.
Emission from benzene excited by pulse radiolysis
Authors: Horrocks A. R.
Published: May 2006

The emission spectra from deaerated benzene solutions of varying concentration, excited by 3 ns duration electron pulses at dose rates of 1013 rads/s are described. These compare favorably with the photoexcited spectra for similar benzene systems. The effects of chloroform and oxygen on the emission from liquid benzene are reported.
Radiolysis of ethyl iodide – chloromethane mixtures
Authors: Leblanc R. M. , West M. A. , Woods R. J. , Herman J. A.
Published: May 2006

Mixtures of ethyl iodide with chloroform, carbon tetrachloride, and dichloromethane have been irradiated with 60Co γ-radiation. Reduced yields of iodine, hydrogen iodide, and hydrogen chloride from ethyl iodide – chloroform and ethyl iodide – dichloromethane mixtures and of chlorinated ethanes from ethyl iodide – chloroform are attributed to radical scavenging by iodine and dissociative electron capture by the chlorinated methane.Electron capture by carbon tetrachloride followed by ion–molecule reactions between ethyl iodide cations and ethyl iodide, or neutralization of these cations by chlorine anions, explains iodine yields observed at low ethyl iodide concentrations in carbon tetrachloride greater than those expected on the basis of partition of absorbed energy. In this mixture, neutralization of an ethyl iodide cation by a chlorine anion gives rise to an enhanced hydrogen chloride yield.
Kinetic deuterium isotope effect in the reaction of methyl iodide with thiosulfate ion in aqueous solution
Authors: Willi Alfred V. , Won Chong Min
Published: May 2006

The kinetic deuterium isotope effect in the reaction of methyl iodide with thiosulfate ion in aqueous solution has been determined as follows: kH/kD (per 3D) = 0.966 (+0.02°), 0.968 (+10.00°), 0.970 (+19.98°). Kinetic experiments have been carried out in reaction vessels with no gas phase. The experimental data are compared with results of model calculations of isotope effects from force constants. Excellent agreement between experimental and calculated isotope effects may be obtained with the following values of the transition state bending force constants: fHCI = 0.295 mdyn Å, fHCS = 0.300 to 0.320 mdyn Å. These values are equal to 50–65% of the corresponding bending force constants in stable molecules.
Infrared study of the state of water in the hydration shell of DNA
Authors: Falk Michael , Poole A. G. , Goymour C. G.
Published: May 2006

The state of water in the hydration shell of DNA was studied by infrared spectroscopy. The stretching bands of isotopically dilute HDO adsorbed on DNA have nearly the same band profiles as those of HDO in liquid water. This indicates a distribution of hydrogen-bond strengths similar to that in liquid water. At low temperatures, the spectra show that an inner layer of about 10 water molecules per nucleotide is incapable of crystallization, even when the surrounding water crystallizes into ice I. The biopolymer hydration shells are not "ice-like" in the sense of crystalline ordering into an ice-like structure.
Cycloaddition reactions. Thermal addition of dimethyl acetylenedicarboxylate to 1-methoxyindene
Authors: Doyle Terrence W.
Published: May 2006

The cycloaddition of 1-methoxyindene 2 to dimethyl acetylenedicarboxylate to form a fused cyclobutene system 3 is discussed. Photochemical ring enlargement of 3 leads to a benzocycloheptatriene system 5 while reduction yields a dihydro derivative 4. Saponification of 3 followed by photochemical ring expansion yields the diacid 7 which is subsequently hydrolyzed and decarboxylated to ketoacid 8.
Appareil pour la mesure de moments dipolaires
Authors: Barbeau C. , Ricard L. , Turcotte J.
Published: May 2006

A system is described which enables the determination of dipole moments of magnitude 1.0 D from as little as 10−4 mole of substance. The dielectric constant can be measured with a precision of ± 0.000008 unit. Only one weighing is necessary. A modified Guggenheim method, in which only the values of the dielectric constant are required, is used to calculate the dipole moments.
Electric discharge reactions of hydrocarbons
Authors: Paciorek K. L. , Kratzer R. H.
Published: May 2006

The electric discharge reactions of five hydrocarbons, ethylene, ethane, propylene, cyclopropane, and propane, were investigated in the presence of a rare gas. Three types of products were formed: hydrogen, a mixture of relatively simple hydrocarbons, and polymeric deposits. The deposition of the polymeric films occurred most readily with olefins. The reactions occurring under the influence of an electric discharge appear to be comparable to the processes taking place in radiolysis.
Contribution à l'étude des mélanges liquides PbCl2–PbO
Authors: Renaud Maurice , Poidatz Emmanuel , Chaix Jean-Edmond
Published: May 2006

The solidification diagram of liquid PbCl2–PbO mixtures was determined for molar fractions of lead oxide smaller than 2/3; three compounds were identified: these are the oxychlorides 3PbCl2,2PbO; PbCl2,PbO, and PbCl2,2PbO. Furthermore, the cryoscopic study of the liquidus of lead chloride led the authors to suggest the existence of the species PbCl2,PbO and the almost complete lack of Cl− ions in the liquid phase.
Infrared spectra of some alkyl platinum compounds. Part I. Comparison with the spectra of chemisorbed hydrocarbons
Authors: Morrow B. A.
Published: May 2006

A series of triphenylphosphine stabilized platinum dialkyl compounds of the type (Ph2P)3PtR2 where R = methyl, ethyl, ethyl-d3, n-propyl, n-butyl, and n-hexyl have been synthesized and their infrared spectra in the CH stretching region have been obtained. These spectra are discussed in terms of the infrared spectra of hydrocarbons which are chemisorbed on transition metal catalysts.
An abnormal reaction of a phosphonium ylide with diethyl ketomalonate
Authors: Ploder Werner H. , Tavares Donald F.
Published: May 2006

An attempted Wittig reaction of o-xylylene-bistriphenylphosphorane with diethyl ketomalonate gave ethyl 3-ethoxy-2-naphthoate, representing formally, a Wittig reaction with an ester carbonyl.
Interferometric investigation of the polarographic maxima
Authors: O'Brien R. N. , Dieken F. P.
Published: May 2006

The flow patterns around the mercury drop at the positive and negative polarographic maxima have been investigated by suspensions of activated carbon particles and laser interferometry. The accepted patterns due to Antweiler have been shown to require modification. Specifically the positive maximum flow is a downflowing annulus with a gently upwelling interior below the equator of the drop and the negative maximum flow is a torroidal whorl surrounding the drop. Speeds of particles were recorded by motion picture photography and concentration changes by interferograms.
Oxidation of hydrocarbons. II. Kinetics of the oxidation of p-toluenesulfonic acid by potassium permanganate
Authors: Lee Donald G. , Singer Brian E.
Published: May 2006

The kinetics of the oxidation of p-toluenesulfonic acid by aqueous potassium permanganate have been studied in perchloric acid solutions ranging from 0.296 to 3.16 M HClO4. Below 1 M HClO4 the rate law is found to be, v = k3[Arene][MnVII]h0 while above 2 M HClO4 it is v = k2[Arene]h0. The values obtained for k3 and k2 are 8.09 ± 0.25 × 10−4 and 1.19 ± 0.13 × 10−7 M−1 s−1 respectively.
Phosphorescence of chloropentafluoroacetone at 77 °K
Authors: Samant H. S. , Yarwood A. J.
Published: May 2006

The phosphorescence of chloropentafluoroacetone at 77 °K is reported and the energy of the triplet state is estimated to be 74 kcal. The phosphorescence lifetimes and the relative phosphorescence yields of chloropentafluoroacetone and hexafluoroacetone at 77 °K were measured. The results show that substitution of a chlorine atom in the fluorinated aliphatic ketone changes the radiative and non-radiative rate constants from the triplet state at 77 °K by factors of about 1.7 and 2.3, respectively.
Assignment and conformational properties of the sugar-ring hydroxyl protons of the common nucleosides
Authors: Davies D. B. , Danyluk S. S.
Published: May 2006

A 60 MHz proton magnetic resonance study has been made of the hydroxyl protons of the ribose and deoxyribose rings for the common nucleosides dissolved in mixtures of dry DMSO-d6 and C6D6. Use of this solvent system permitted the detection and assignment of the exchange-free spin-coupled multiplets for the hydroxyl protons. The assignment was confirmed by spin-decoupling experiments.Based on the magnitudes of the observed coupling constants, it is concluded that the O—H5′, group is freely rotating around the C5′—O5′ bond. It is calculated that the O—H3′ bond favors a gauche conformation relative to the C3′—H3′ bond, consistent with the preferred conformation found in the solid state for the H3′—C3′—O3′—P bonds of the nucleoside 3′-phosphates. The conformation of the O—H2′ bond relative to the C2′—H2′- bond demonstrates no preference for the gauche rotamer. Such a rotamer might be expected if a hydrogen-bond between the 2′-OH and the purine base exists in this solvent system, as well as in aqueous solutions where such an interaction has been postulated as a stabilizing influence for ribosides.
The hydrogenation of allene. III. The reaction of allene with hydrogen catalyzed by nickel, copper, and their alloys
Authors: Mann R. S. , Shah A. M.
Published: May 2006

The reaction between allene and hydrogen over unsupported nickel, copper, and their alloys has been investigated in a static constant volume system between 26 and 131 °C for a wide reactant ratios. The orders of reaction with respect to hydrogen and allene were one and zero, respectively, and temperature independent. The reaction over metals and their alloys is largely simple hydrogenation, the early stages being principally a selective formation of propylene, with small yields of reduced polymers of allene. The overall activation energies varied between 4.8 and 11.8 kcal/g-mole. Selectivity was highest with copper and least with nickel. The amount of allene polymerized was not related in any particular way to the copper content of alloy.
Termolecular ion–molecule reactions involving C3H5+
Authors: Harrison A. G. , Herod A. A.
Published: May 2006

The reaction of C3H5+ with C2D4 to produce C5H5D4+ is shown to be second order in C2D4. The rate coefficients are in the range 10−24 to 10−25 cm6 molecule−2 s−1 but decrease markedly with increasing ion kinetic energy. This decrease reflects the effect of the ion kinetic energy on the lifetime of the initial collision complex. Small differences in rate coefficients are observed depending on the source of the C3H5+ ion but these are insufficient to distinguish between possibly different ionic structures. The reaction of C3H5+ with C2H3F forms C5H7+ in a reaction second order in C2H3F. The rate coefficients are also in the range 10−24 to 10−25 cm6 molecule−1 s−1 and show a similar dependence on ion kinetic energy. These high third order rate constants are compared with data for other termolecular reactions and are shown to be consistent with the effect of molecular size on the third order rate constant.
Complexes of Group III trimethyls with diamines
Authors: Storr A. , Thomas B. S.
Published: May 2006

Direct combination of the Lewis acids, Me3M (where M = B, Al, Ga, or In), and the diamines, Me2N(CH2)nNMe2 (where n = 1, 2, or 3) has given two series of complexes. A range of 1:1 complexes can be isolated with Me2NCH2NMe2 as ligand. With the other diamines, use of a 1:1 molar ratio of reactants yields crystalline 2:1 complexes with two moles of Me3M per mole of ligand. Excluding the reaction between Me3B and Me2NCH2NMe2, 2:1 complexes can be isolated by reacting the various Lewis acids with the appropriate molar quantity of the diamines. The complexes have been characterized by i.r. and proton n.m.r. spectroscopy and molecular weight measurements.A number of complexes of Me3Ga with methyl substituted ethylenediamines have been prepared and the effects of substitution on the nitrogen ligand atoms studied. Pyrolysis of these complexes has demonstrated the ready elimination of methane and has resulted in the formation of condensed Ga—N species.
Temperature dependence of the 1555 cm−1 infrared absorption band in liquid D2O: inflection points
Authors: Oder R. , Goring D. A. I.
Published: May 2006

The temperature dependence curves of the peak height, frequency, and half-width of the infrared intermolecular combination band absorbing at 1555 cm−1 in liquid D2O has been observed to behave sigmoidally between 5 and 70 °C. No evidence of sharp discontinuities has been obtained but inflection points in the rather broad temperature interval of about 25 to 40 °C have been observed. Results are discussed in terms of structural changes occurring in the liquid.
Studies in solvolysis. Part II. Some comments on the ion-pair mechanism for displacements at a primary carbon atom
Authors: Scott John M. W.
Published: May 2006

The implication of Sneen and co-workers (2–5) that all SN2 substitutions at a primary carbon atom probably proceed via the intermediate production of an intimate ion-pair is examined with respect to the reactions of the methyl halides (MeX; X = F, Cl, Br, I) with various nucleophiles (H2O, OH−, F−, Cl−, Br−, I−, CN−, CSN−, S2O32−) in water. By establishing certain rules concerning the behavior of derived reactivity scales (essentially ρ values) as contrasted with absolute reactivity scales (observed rate constants), it is concluded that Sneen and Larsen's mechanistic description is consistent with the experimental facts, and that in such cases the substitution process involves a pre-equilibrium constant, Ke, which is independent of the attacking nucleophile. This is followed by a rate determining bimolecular rate constant, kn, which depends on the ion pair and the nature of the nucleophile. The observed rate (k°) is given by k = Kekn. A method of calculating Ke is described and values of kn for nine nucleophiles attacking the four methyl halide ion-pairs are reported along with a number of confirmatory calculations. It is concluded that the classical Hughes–Ingold SN2 Heitler–London description of these reactions is inadequate. Some further suggestions to place the new mechanistic description on a firmer experimental basis are made.
Infrared and Raman spectra and vibrational assignment of methylene cyclopropane-h6 and -d6
Authors: Bertie J. E. , Norton M. G.
Published: May 2006

Infrared spectra have been recorded in the range 4000 to 20 cm−1 for methylene cyclopropane-h6 and -d6 in the gas phase, and from 4000 to 200 cm−1 for methylene cyclopropane-h6 in the liquid phase. Raman spectra have been recorded for the liquid phases of both species. The fundamental modes of vibration have been assigned using i.r. band contours and Raman depolarization ratios, with the exception of the i.r. inactive A2 modes which were not observed. An interesting feature is the occurrence of remarkably small isotope shifts for certain modes.
Photolysis of Acyl Group IV Metalloids: the Formation of Silyl Radicals
Authors: Brook A. G. , Dillon P. J. , Pearce R.
Published: May 2006

The photolyses of several acylsilanes and one acylgermane in carbon tetrachloride have been shown to involve Norrish Type I cleavage of the metalloid-acyl bond to give metalloidal radicals. These radicals readily abstract chlorine from the solvent.
Synthesis of 6-Hydroxyfulvenes. I. Acid-catalyzed Rearrangements
Authors: McCulloch A. W. , Stanovnik B. , Smith D. G. , McInnes A. G.
Published: May 2006

New syntheses of 2-carbomethoxy-, 2-carboxy-3-carbomethoxy-, 2,3-dicarboxy-, and 2,3-dicarbo-methoxy-4,6-dimethyl-6-hydroxyfulvenes are described.
Addition of Iodonium Nitrate to Unsaturated Hydrocarbons
Authors: Diner U. E. , Lown J. W.
Published: May 2006

Iodonium nitrate in chloroform-pyridine at room temperature undergoes a trans stereospecific electrophilic addition to alkenes to form (i) iodoaliphatic nitrate esters, (ii) iodoalkane pyridinium nitrates, or (iii) alkene pyridinium iodides depending on the substrate. The addition is sensitive to steric hindrance effects and anti-Markovnikov addition is commonly encountered. In similar additions to conjugated dienes 1,2-additions in a Markovnikov fashion to form 1:1 adducts of type (ii) are the rule. Terminal acetylenes give alkynyl iodides in fair yield.
Potassium Methylamide: Preparation and Infrared Spectrum
Authors: Makhija R. C. , Staris R. A.
Published: May 2006

Potassium methylamide has been prepared by a convenient method using potassium hydride. The i.r. absorption spectrum is reported.
Synthesis and Stereochemical Assignments of Some Trifluoromethylphenylcyclopropanes
Authors: Altman L. J. , Bramwell M. R. , Vederas J. C.
Published: May 2006

Stereochemical assignments of a series of substituted cis- and trans-1-trifluoromethyl-2-phenylcyclo-propanes (unsubstituted, bromide, carbonitrile, and carboxamide) based on a detailed analysis of the n.m.r. spectra and on the ten-fold difference in rates in the reaction of cis- and trans-1-trifluoromethyl-2-phenylcyclopropyl carbonitrile with basic hydrogen peroxide are presented.
The Mechanism of Oxygenation Reactions Catalyzed by Rhodium(I) Complexes in Solution
Authors: James B. R. , Ochiai E.
Published: May 2006

The mechanism of oxygenation reactions catalyzed by a rhodium complex which forms a 1:1 molecular oxygen adduct has been elucidated by infrared spectroscopy. Hydrogen abstraction from the substrate by the coordinated oxygen is involved, and the data give the first direct evidence for hydroperoxide intermediates in such reactions of d8 metal complexes.
Photoconductivity of γ-Irradiated Methyltetrahydrofuran Glass at 77 °K
Authors: Baverstock K. F. , Dyne P. J.
Published: May 2006

not available
Infrared and Raman Spectroscopic Studies of Solid Alkali Metal Nitrites
Authors: Brooker M. H. , Irish D. E.
Published: May 2006

Infrared and Raman spectra of solid LiNO2•H2O, LiNO2, NaNO2, KNO2, and CsNO2 are presented and discussed. Pronounced changes in the spectra of LiNO2•H2O during dehydration to anhydrous LiNO2 are interpreted as evidence for an ordered distribution of NO2− ions over two non-equivalent sites (akin to linkage isomerism) in anhydrous LiNO2. The frequencies of the internal modes of the nitrite ion shift to lower values with increasing cation size. Vibrational bands due to nitrate ion present as an impurity are assigned.
Chemical Shift. VI. The Long-range Shielding Effects of Ethylene–Ketal and −Thioketal Groups
Authors: ApSimon J. W. , Beierbeck H. , Todd D. K. , Demarco P. V. , Craig W. G.
Published: May 2006

The calculation of chemical shift values by the method used in parts I–V (1–5) has been extended to a derivation of the shielding effects of the ethylene–ketal and −thioketal groups. For these studies ketal and thioketal derivatives of monoketoandrostanes were prepared. The chemical shifts of the C-18 and -19 methyl protons in these compounds are reported for the solvents CDCl3, CCl4 and benzene.Representing both groups by point dipoles, values for the anisotropies and for K, a parameter descriptive of the electric field effect, were derived for various, coincidental, locations of the magnetic and electric dipoles along the symmetry axes of the two groups.
The Nickel(II)–γ-Picoline–Perchlorate Complex System
Authors: Sun M. S. , Brewer D. G.
Published: May 2006

Three compounds have been isolated; viz., NiL4(ClO4)2, NiL4(H2O)2(ClO4)2 and NiL6(H2O)2(ClO4)2 (L = γ-picoline), and their spectral, magnetic, and other properties compared. Some tentative suggestions as to the possible structure of the last complex are offered; the first two compounds were reported previously (1).
The Reaction of S(3P) Atoms with Molecular Oxygen
Authors: Fair R. W. , Roodselaar A. Van , Strausz O. P.
Published: May 2006

The rate constant of the reaction of ground state S(3P) atoms with molecular oxygen, S(3P) + O2(X3Σg−) → SO(X3Σ−) + O(3P), has been determined as (1.7 ± 0.2) × 1012 cm3 mol−s− at 298 °K by means of kinetic spectroscopy in the vacuum ultraviolet region. The source of S(3P) atoms was the isothermal flash photolysis of COS in the presence of Ar or CO2.
Hydrates of Tetra-n-butylammonium Picrate in Benzene and Chlorobenzenes
Authors: Goldman Saul , Cave G. C. B.
Published: May 2006

The first two hydration constants of the ion pair tetra-n-butylammonium picrate in the solvents o-di-chlorobenzene, chlorobenzene, and a binary mixture benzene–chlorobenzene (1:1 v/v) at 25.0, 35.1, and 45.1 °C were determined by an isopiestic method. In addition, algebraic treatment of the data permitted evaluation of the hydration constants of the dimer and higher aggregates known to co-exist with the monomer in the solutions. The effect of bulk dielectric constant of the solvent on the hydration constants of the monomer is discussed.
Gas-Solid Exchange Reactions: Zinc Vapor and Monocrystalline Zinc Telluride
Authors: Secco E. A. , Yeo Richard Swee-Chye
Published: May 2006

The exchange reaction between radioactive zinc vapor and single crystals of zinc telluride was studied in a static system in the temperature range 760–860 °C and PZn = 0.10 atm.The experimental rate data are consistent with a diffusion process which is interpreted in terms of a simple vacancy mechanism. The diffusion coefficient is given by[Formula: see text]
On the Intermediate in the Reaction of Diethyl Malonate with 1-Fluoro-2,4-dinitrobenzene
Authors: Leffek K. T. , Tremaine P. H.
Published: May 2006

No evidence has been found for a stable intermediate during the reaction of 1-fluoro-2,4-dinitrobenzene with diethyl malonate in the presence of triethylamine as has been reported in the literature. The spectral and chemical properties attributed by earlier work to the intermediate have been assigned to the final products of the reaction.
Reactions of 1-Substituted 5-Tetrazolyllithium Compounds; Preparation of 5-Substituted 1-Methyltetrazoles
Authors: Raap R.
Published: May 2006

1-Methyl-5-tetrazolyllithium undergoes fragmentation to nitrogen and lithium methylcyanamide at temperatures exceeding −50°. Below −60° it is however fairly stable and a useful reagent for the preparation of various 5-substituted 1-methyltetrazoles. It reacts readily with halogens, cyanogen bromide, sulfur, aldehydes, ketones, and acid chlorides but not appreciably with benzyl bromide and benzonitrile. With methyl benzoate it forms a labile addition compound which can be hydrolyzed to 5-benzoyl-1-methyl-tetrazole.1-Phenyl-5-tetrazolyllithium rapidly decomposes to lithium phenylcyanamide at temperatures as low as −65° to −70°.
Etude des spectres de vibration de l'isothiazole et des spectres infrarouges de trois mono et dideutério isothiazoles
Authors: Meyer Jean-Louis , Davidovics Gisele , Chouteau Jacques , Poite Jean-Claude , Roggero Jean
Published: May 2006

The 4- and 5-monodeuterio and 4,5-dideuterio isothiazoles were prepared and their i.r. spectra recorded in different states, vapor particularly.The Raman spectrum of isothiazole was also measured; its analysis leads to the modification of the assignment of two of the fundamental modes previously described for this compound. The analysis of the i.r. spectra of the three deuterio isothiazoles is discussed.
Base-catalyzed Dehydrobromination of Several α-Bromoacetals
Authors: Davis H. A. , Brown R. K.
Published: May 2006

Base-catalyzed dehydrohalogenation with potassium t-butoxide in t-butyl alcohol of the acetals obtained from homologues of α-bromoacetaldehyde and ethylene glycol[2-(α-bromoalkyl)-1,3-dioxo-lanes] or 1,3-propanediol[2-(α-bromoalkyl)-1,3-dioxane] provides the corresponding ketene acetal, in some cases exclusively and in others as the major product along with a smaller proportion of the α,β-unsaturated acetal. In contrast, similar dehydrohalogenation conditions convert the acetals obtained from homologues of α-bromoacetaldehyde and monohydroxy alcohols, to the α,β-unsaturated acetals, in some cases exclusively, and in others as the major product accompanied by a smaller proportion of the corresponding ketene acetal.The preference for the ketene acetal formation from the 2-(α-bromoalkyl)-1,3-dioxolanes (the ethyleneacetals) is believed due to greater ease of approach by base to the methine proton as a result of the restricted shape of the 1,3-dioxolane ring. Approach by base to the methine proton of the α-bromoalkyl dialkylacetals is more hindered by the two alkoxy groups, which cause preferred attack by base at the β proton to provide the α,β-unsaturated acetal.The proportion of α,β-unsaturated acetal obtained from base-catalyzed dehydrohalogenation of 2-(α-bromoalkyl)-1,3-dioxolanes can be greatly increased if the reaction is carried out in dimethyl sulfoxide. This marked change in proportion of products is thought to be due to a change in mechanism occasioned by the dimethyl sulfoxide.
A Method for Gas-Liquid Chromatographic Identification of O-Methyl Ethers of 2-Deoxy-2-methylamino-D-glucose and 2-Deoxy-2-methylamino-D-galactose
Authors: Gorin P. A. J. , Magus R. J.
Published: May 2006

A method is described for the g.l.c. identification of O-methyl ethers that can be formed on methylation–fragmentation analysis of polymers containing 2-acetamido-2-deoxy-D-glucopyranose or 2-acet-amido-2-deoxy-D-galactopyranose units. The possible 2-deoxy-O-methyl-2-methylamino-D-glucoses and -D-galactoses and their derived hexitols, were converted to their acetates and trimethylsilyl ethers. The g.l.c. was carried out using a number of liquid phases and the retention times of the derivatives were found to be sufficiently diverse to make positive identifications of unknowns feasible.
The Electroreduction of Periodate Anion in Alkaline Media
Authors: Fawcett W. R. , Lee Y. C. Kuo
Published: May 2006

The electroreduction of periodate anion was studied at a dropping mercury electrode in aqueous solutions in the pH range 11–13.3 where the process is markedly affected by the double layer. The electrode reaction was found to be complex, its mechanism depending on both pH and ionic strength. The effects of the double layer on the component reactions are discussed with respect to current theoretical developments.
Étude cinétique de quelques cellules électrochimiques de métaphosphate de sodium (NaPO3) fondu
Authors: Casey E. J. , Dubois A. R.
Published: May 2006

Interest in the possible use of molten metaphosphates as electrolyte and as reactant in electrochemical cells has been examined from the points of view of both electrochemical synthesis and sources of electrical energy. Both are shown to be possible.The anodic evolution of O2 from carefully dried molten NaPO3 on Pt shows hysteresis in the V/I curve, and also shows Tafel behavior (dη/d log i = 2.3RT/βnF) with surprising exactness, which implicates one-electron slow discharge as rate-determining over a considerable range of rate of reaction. The cathodic process is complex, but includes deposition of Na into the Pt if the melt is dry.On Ni the phosphide Ni12P5 predominates as the autocorrosion product. This material is actively reduced if electrochemically coupled with Ca, and can be electrochemically oxidized by O2. Forced electrolysis inserts extra nickel into a phosphide anode, or phosphorus into a phosphide cathode, and modifies its crystal structure. The trimeric structure of the melt is modified by electrolysis, as shown by DTA tracings, by phosphorus-n.m.r. spectra, by changes of color and of solubility of the products in water. Anolyte product differs from catholyte product. The electrolyzed melt can leak charge both electronically and electrolytically at 650 °C, but electronic transport is tenuous and seems to be determined by an injection process at the cathode. Reactions and mechanisms are proposed for the various processes, including a phosphate shuttle to account for loss of charge.Indications are that metal phosphides, phosphorus, phosphine, polymeric metaphosphates with various physical properties, metal cladding, and semiconducting metallo-phosphorus products could be selectively produced if sufficient controls were to be imposed on a suitably designed electrochemical reactor.
Quasichemical Treatment of the Solubility of Reactive Gases in Fused Salts
Authors: Block-Bolten A. , Flengas S. N.
Published: May 2006

A quasichemical model applicable to solubilities of reactive gases in fused salts has been developed. The treatment is based on local ordering effects, and accounts for next-nearest neighbor anion repulsions.The present calculation is applicable to common ion fused salt systems where complex ions with a pronounced heat of formation do not form. The treatment allows the evaluation of structural parameters from available experimental data.
Studies on Acyl Alkyl Diimides
Authors: Lynch Thomas R. , MacLachlan Frederick N. , Siu Yum Kuen
Published: May 2006

not available
Réaction des acétoxy-1 époxy-2,3 cyclohexanes cis et trans avec le tributylcarbéthoxyméthinephosphorane
Authors: Favre H. , Lapointe J. P.
Published: May 2006

Four different products were obtained by the reaction of cis-1-acetoxy-2,3-epoxycyclohexane with tri-n-butyl-carbethoxymethylidenephosphorane: cyclopent-1-enaldehyde (5), ethyl-3-(cyclopent-1-enyl)-propeonate (6), trans-ethyl-3-(2-c-acetoxycyclopentyl)propeonate (7), and its isomer 8, in a 8–20–12–60 ratio, with a yield of 70%. The same products were obtained when a mixing of acetoxyepoxydes 3 and 4 were used in a 38–62 ratio.
Preparation and Structural Elucidation of cis-and trans-Phenyl-2-methylcyclohexanol
Authors: Rutherford K. G. , Wassenaar S. , Brien J. F. , Fung D. P. C.
Published: May 2006

The preparation of cis- and trans-1-phenyl-2-methylcyclohexanol by hydrolysis of an isomeric mixture of the corresponding hydrogen phthalate esters is described. The elucidation of the structures of the alcohols is also described.
The Hydrogen–Oxygen Reaction on Lanthanide Oxides. I. Hydrogen and Oxygen Adsorption on Some Lanthanide Oxides
Authors: Read John F.
Published: May 2006

Hydrogen and oxygen adsorption have been measured on neodymium oxide and dysprosium oxide from 77 to 771 °K up to equilibrium pressures of approximately 6 Torr. In addition, hydrogen adsorption measurements have been made on samarium oxide and gadolinium oxide from 77 °K to approximately 100 °K. The adsorption is effectively instantaneous in all cases except for oxygen adsorption on neodymium oxide at 491 and 541 °K. Adsorption appears to be dissociative for all cases studied except for hydrogen adsorption on neodymium oxide at all temperatures and for hydrogen adsorption on dysprosium oxide at high temperatures. For neodymium oxide and dysprosium oxide three types of adsorption are observed in different temperature ranges. At low temperatures, the adsorption is probably physical; at intermediate temperatures, it is either physical, or chemical on isolated double sites; and at high temperatures it is chemical. In general, the Freundlich isotherm gives the highest correlation between calculated and experimental data. The isosteric heat of adsorption and the equilibrium uptake of hydrogen increase as the ionic radius of the metal ion decreases.
The Master Equation for the Dissociation of a Dilute Diatomic Gas. VI. Solution of Coupled Sets of Master Equations
Authors: McElwain D. L. S. , Pritchard H. O.
Published: May 2006

Three coupled sets of master equations, representing the equilibration of [Formula: see text] via atoms only, have been solved by the normal-mode technique; the set of 57 simultaneous differential equations describing the H2/D2/2HD system was considered as a suitable trial model. It was found that at times (t) in excess of the longest vibrational relaxation time, even though some of the populations in the system appeared highly non-Boltzmann, all the phenomenological rate constants were well-behaved: they were either constant and obeyed the rate–quotient law, or they were dependent on t2.The paper concludes with a discussion of the information required before a full solution of the [Formula: see text] reaction could be contemplated, and suggests methods by which an approximation to such a solution could be obtained.
Secondary Kinetic Isotope Effects in Bimolecular Nucleophilic Substitutions. VI. Effect of α and β Deuteration of Alkyl Halides in their Menschutkin Reactions with Pyridine in Nitrobenzene
Authors: Leffek K. T. , Matheson A. F.
Published: May 2006

A survey of kinetic, secondary deuterium isotope effects, for α, β, and γ deuterated alkyl halides reacting with pyridine in nitrobenzene solvent has been made. α-Deuterium effects have been measured for eight compounds, β-deuterium effects for four compounds, and one rate ratio for γ-deuteration is reported. The possible errors in the rate ratios for β-deuterated compounds, resulting from the elimination side reaction have been determined. The results are discussed in terms of transition state structure.
Etude par spectrométrie de vibration des composés d'addition formés entre le chlorure ou le bromure d'aluminium et le dimethylsulfoxyde
Authors: Meunier J. , Forel M. T.
Published: May 2006

Coordination compounds between AlCl3 or AlBr3 and (CH3)2SO or (CD3)2SO have been prepared. Two different solid compounds (AlX3)• (dmso)1.5 and AlX3• (dmso)6 have been characterized. The vibration spectra show that they are ionic, [Formula: see text] (I) and [Al(dmso)6]3+•3X− (II). A complete assignment is proposed. Results are in good agreement with a D3d symmetry for the cation of compound (I) and C2h for the cation of compound (II). Strong interaction between the X− ions and the methyl groups of the form (II) exist.The (Al—O) bond force constant is close to 1.8 × 105 dynes cm−1.
The Formation of Alkenes by the Thermal Elimination Reaction of N-Methyl-4-Alkoxypyridinium Iodides. I. Scope of the Reaction
Authors: Schmid George H. , Wolkoff Aaron W.
Published: May 2006

Twenty-one 4-alkoxypyridines and their corresponding N-methyl-4-alkoxypyridinium iodides have been prepared and the latter pyrolyzed at temperatures ranging from room temperature to 185° to give the olefins derived from the alkyl moiety in high yields.
Metal–Ammonia Reduction. Part I. The Reduction of α,ω-Diarylalkanes and Triphenylmethanes
Authors: Butler D. N. , Milburn R.
Published: May 2006

The Birch reductions of 15 α,ω-diarylalkanes, 1a, b, c (n = 1–5) and of triphenylmethane (3a) and tris(p-methoxyphenyl)methane (3b) are described. In every case reduction proceeds independently in each ring to furnish the products, namely, α,ω-bis(2′,5′-dihydroaryl)alkanes, 2a, b, c (n = 1–5), and tris(2′,5′-dihydroaryl)methanes, 4a, b.Acid hydrolysis of the enol ethers 2b, c (n = 1–5) and 4b affords the corresponding ketones 6 (n = 1–5), 7 (n = 1–5), and 8.
Non-Steady-State Kinetics for a Double-Intermediate Enzyme Mechanism: The Case of High Enzyme Concentrations
Authors: Huazi Nasrat H. , Laidler Keith J.
Published: May 2006

An equation has been derived for the non-steady-state kinetics arising from the mechanism[Formula: see text]in which the concentration of enzyme E is greatly in excess of that of the substrate A; EA and EA′ are two intermediates and X and Y the products. Solutions for the rate of formation of the first product X were given by Kasserra and Laidler. The present work is concerned with the rate of formation of Y. A general equation is derived for the rate of production of Y, and it is shown that under certain simplifying conditions, easily realized in practice, the rate law reduces to [Formula: see text] study of the rate of formation of Y therefore leads to a determination of k3.
The Influence of the 2-Alkoxy Group and of C-5 Substituents on the Direction of Reductive Cleavage of 2-Alkoxytetrahydrofurans by AlH2Cl in Ether Solution
Authors: Loewen P. C. , Makhubu Miss L. P. , Brown R. K.
Published: May 2006

The AlH2Cl hydrogenolysis of ether solutions of 2-alkoxytetrahydrofurans in which the alkoxy group is either CH3O, C2H5O, i-C3H7O, or t-C4H9O, gives only those products resulting from ring C—O bond cleavage. However, substituents at C-5 of 2-methoxytetrahydrofuran exert a strong effect on the ratio of ring to exo C—O bond cleavage. Thus, alkyl (electron donor) groups at C-5 promote an increase in the amount of exo cleavage, the proportion increasing from 62.5 to 100% as the C-5 alkyl group is changed from CH3 to t-C4H9. In contrast, electron withdrawing substituents, CH3OCH2— and C6H5, at C-5 favor ring cleavage to the extent of 93 and 84% respectively.The results are interpreted in terms of the influence that these substituents exert through their electronic properties on the relative ease of attainment of the transition state leading to either ring C—O or exo C—O bond cleavage. However, evidence is provided to show that the bulk steric effect of these substituents also controls, though to a minor extent, the proportion of ring to exo cleavage.
Conformational Studies on the 1,2;5,6-Di-O-isopropylidene-D-hexoses
Authors: Hall L. D. , Black S. A. , Slessor K. N. , Tracey A. S.
Published: May 2006

Nuclear magnetic resonance studies on the 1,2;5,6-di-O-isopropylidene-D-hexofuranose sugars have provided information on the conformational preferences of the five-membered rings in these molecules. They appear to have strong conformational preferences rather than existing as freely pseudorotating systems. The furanose rings of the 3-deoxy-ribo and lyxo derivatives are found to preferentially exist in an envelope conformation in which C-4 is displaced from the plane of the ring. The arabino and xylo derivatives are found to be much less distorted, with preferred conformations approaching twist forms involving displacements of C-1 and -2. Substitution of various endo and exo groups at C-3 appears to have only minor influence on the parent furanose conformation.
Stereochemistry of the Cycloaddition of Singlet Excited β-Substituted Styrenes to Olefins
Authors: Chapman O. L. , Lura R. D. , Owens R. M. , Plank E. D. , Shim S. C. , Arnold D. R. , Gillis L. B.
Published: May 2006

The photocycloaddition of β-substituted styrenes (trans-cinnamic acid (1b), methyl trans-cinnamate (1c), trans-cinnamonitrile (1d), and cis-cinnamonitrile) to olefins occurs with retention of stereochemistry and involves the S1 state. In certain cases (1b, c) a photoene reaction competes with the cycloaddition. The triplet states of the β-substituted styrenes produced by sensitization give only [Formula: see text] isomerization. Neither cycloadduct nor photoene reaction is observed from the triplet states. It is thus likely that both addition and photoene reactions involve the S1 state of the β-substituted styrene.
The Oxidation of 2-Propanol by Ruthenium Tetroxide
Authors: Lee Donald G. , Engh Matthijs van den
Published: May 2006

The kinetics of the oxidation of 2-propanol by ruthenium tetroxide in aqueous perchloric acid solutions have been investigated. The results indicate that the two mechanisms pertain; at moderate acidities (1–6.5 M HClO4) the rate determining step involves hydride abstraction while at very high acid concentrations the rate determining step becomes carbonium ion formation.
The Magnetic Susceptibilities of Some Oxyhalide Ions
Authors: Kennedy M. B. , Lister M. W.
Published: May 2006

Diamagnetic susceptibilities are reported for aqueous sodium hypochlorite, chlorite, hypobromite, and bromite. The results, combined with data from the literature for compounds of general formula NaXOn, show a small increase for n = 0 to 2, and a much larger increase thereafter. The interpretation of these results in terms of bond orders is discussed, and comparisons are made with the enthalpies of formation, distances, and force constants of these compounds.
Réactions des phosphites triméthylique, triéthylique, et triphénylique avec le cholestérol
Authors: Benezra Claude , Bravet Jean-Louis , Riess Jean
Published: May 2006

With cholesterol, trimethyl and triethyl phosphites afford dicholesteryl phosphonate HP(O)(OCholest)2 (6) and an unsymmetrical phosphonate HP(O)(OR)(OCholest) (5, R = CH3 and C2H5 respectively) while triphenyl phosphite gives exclusively the phosphonate 6. Those results are discussed in terms of a possible mechanism of these reactions.
Etude des oxyphosphoranes en tant qu'intermédiaires lors de la réduction de l'ozonide du styrène par les phosphites
Authors: Carles J. , Fliszâr S.
Published: May 2006

The kinetic study of the reduction of styrene ozonide by various phosphites suggests the formation of an oxyphosphorane intermediate. A reevaluation of the mechanism of ozonolysis of selected oxyphosphoranes having a C—C double bond is presented.
INDO MO Calculations of the Conformational Dependence of the vicinal 13C,H Spin–Spin Coupling Constant in Propane
Authors: Wasylishen R. , Schaefer T.
Published: May 2006

Molecular orbital theory at the INDO level of approximation is used to calculate the Fermi contact contribution to three-bond carbon–proton coupling constants in propane. The calculations predict a dihedral angle dependence of 3J(13C,H) in the 13C—C—C—H fragment similar to that observed for 3J(H,H), 3J(19F,H), and for 3J(31P,H) in the saturated X—C—C—H fragments.