1859-09-2Relevant articles and documents
n-Caprylammonium Chloride: A Solid Membrane Model
Schenk, K. J.,Ogle, C. A.,Schwarzenbach, D.,Chapuis, G.,Cornut, J.-C.,Rey-Lafon, M.
, p. 5530 - 5536 (1992)
n-Caprylammonium chloride (C8Cl) undergoes three thermotropic phase transitions between 304 and 311 K.Its high-temperature phases (β, γ, and α) are very disordered and resemble smectic mesophases found in biomembranes.The δ-phase (stable between 278 and 304 K) of C8Cl is studied by means of single-crystal X-ray diffraction.Chlorine and nitrogen atoms form a 3-periodic arrangement, but the carbon atoms oscillate about the long axes of the n-caprylammonium chains.These exist as several conformers which can be approximated as a single, entirely extended chain.The cell of the δ-phase allowed us to index powder X-ray photographs of the other phases of C8Cl and to deduce a structural description for them.Percentages of conformers, G forms, and GTG'/GTG sequences in the various phases are estimated from the analysis of characteristic IR and Raman bands, especially of the ω-bideuterated derivative.By a combination of our conclusions with previous NQR and NMR results, a rather complete picture of the phase transitions is deduced: they are brought about by the disordering of the aliphatic chains on one hand and of the hydrogen bonding scheme at the Cl-N interface on the other hand.The dynamics of these two subsystems behave quite differently indeed: changes in the chains occur very gradually, whereas variations in the interface happen quite abruptly.C8Cl successfully mimics the temperature dependence of the bilayer thickness, chain cross section, and order as well as the chain separation/interdigitation transition in biological membranes.
ESR, Structure, and reactions of Specifically Deuterium-Labeled Pentane Cations in X-Irradiated Freon Matrices
Dolivo, G.,Lund, A.
, p. 3977 - 3984 (1985)
Solutions of 1-2 mol percent of pentane, pentane-3-d2, pentane-2,4-d4, and pentane-1,5-d6 in CFCl3, CF3CCl3, and CF2ClClFCl2 have been X irradiated at 77 K.ESR spectra of the molecular ions were recorded at temperatures between 77 K and either the glass transition temperature for CF3CCl3 (140 K) and CF2ClClFCl2 (about 110 K) or the melting point for CFCl3 (162 K).It was found that the pentane molecular ions in these matrices have not only the structure of an extended chain, but also that of several gauche conformers.Their identity and proportions depend on the matrix and on the labeling.INDO calculations were made to elucidate the detailed structure of the conformers of the pentane molecular ions in these matrices.Tilting both methyl groups toward the central-CH2- leads to a significant decrease in the energy of the ion with a minimum at about 90 deg and to significant changes in hyperfine coupling constants, giving a much better agreement with experimental data.Isotope effects were discovered for the deprotonation reaction in CF2ClCFCl2 and especially for the photofragmentation in CF3CCl3.
Gas-Phase Chemistry of CH3SOH, (-)CH2(+)SHOH, CH3SO(.), and (.)CH2SOH by Neutralization-Reionization Mass Spectrometry
Turecek, Frantisek,Drinkwater, Donald E.,McLafferty, Fred W.
, p. 7696 - 7701 (1989)
The kinetically unstable molecules methanesulfenic acid (CH3SOH, 1) and its ylide isomer ((-)CH2(+)SHOH, 2) and the isomeric radicals CH3SO(.) and (.)CH2SOH exist as distinct species in the gas phase.CH3SOH was generated by flash-vacuum pyrolysis of methyl tert-butyl sulfoxide and by neutralization of the corresponding cation radical.The ylide (-)CH2(+)SHOH was prepared by neutralizaton of the distonic ion, (.)CH2(+)SHOH, generated from di-n-butyl sulfoxide by double hydrogen rearrangement.Upon collisional activation CH3SOH decomposes to CH3(.) and (.)SOH, while(-)CH2(+)SHOH affords mainly (.)CH2SH and (.)OH.Collisionally activated dissociation (CAD) spectra of the corresponding ions also distinguish these (C,H4,O,S)(.+) isomers.The isomeric radicals CH3SO(.) and (.)CH2SOH and ions CH3SO(+) and CH2SOH(+) were characterized through their neutralization-reionization and CAD mass spectra, respectively.Decomposition mechanisms consistent with deuterium labeling are proposed, and the relative stabilities of the (C,H4,O,S) isomers are estimated by MNDO calculations.
PROCESS FOR THE PREPARATION OF DEUTERATED ETHANOL FROM D2
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Paragraph 0135-0141; 0142-0144, (2018/11/21)
The invention relates to a process for the preparation of a deuterated ethanol from an acetic acid, an acetate, or an amide by reaction with D2 in the presence of a transition metal catalyst.
Bioconversion of D-glucose in heavy water: Effect of water isotopomeric composition on deuterium fragment distribution in ethanol
Sakhabutdinov,Bisikalo,Kushnarev,Rokhin,Kulagina
experimental part, p. 2058 - 2061 (2011/05/07)
The relative distribution of deuterium between methyl and methylene groups in ethanol at the bioconversion of D-glucose in heavy water was studied.
Raman spectroscopy of n-pentyl methyl ether and deuterium labelledanalogues
Bowen, Richard D.,Edwards, Howell G. M.,Farwell, Dennis W.,Morgan, Sara E
experimental part, p. 1725 - 1734 (2012/04/04)
The Raman spectra of n-pentyl methyl ether, C5H 11OCH3, and six selectively deuteriated analogues arereported and discussed. Correlations between the observed ν(sp 3CH)stretching and bending bands and the position of the deuterium atoms in thealkyl chain are developed and refined. Similar progress is possible inassociating specific skeletal vibrations with bands in the Raman spectra. Therelevance of this study to improving the assignment of bands in the Ramanspectra of larger systems of biological interest is highlighted. Copyright
Stereospecificity of hydride transfer during the dismutation of aldehydes catalyzed by alcohol dehydrogenases
Velonia,Smonou
, p. 3119 - 3123 (2007/10/03)
The stereochemistry of the oxidation of aldehydes to acids with alcohol dehydrogenases was studied with respect to the selectivity towards the cofactor.
Intermediacy of ion neutral complexes in the fragmentation of short-chain dialkyl sulfides
Filsak,Budzikiewicz
, p. 601 - 610 (2007/10/03)
The main fragmentation processes after electron ionization of butyl methyl and butyl ethyl sulfides are rationalized by the intermediacy of the ion neutral complex [RSH · methylcyclopropane](+·) as demonstrated by extensive labeling and collision activation studies.
The synthesis of [2-2H1]Thiirane-1-oxide and [2,2-2H2]Thiirane-1-oxided and the diastereoselective infrared laser chemistry of [2-2H1]Thiirane-1-oxide
Gross, Heike,Grassi, Guido,Quack, Martin
, p. 441 - 448 (2007/10/03)
We report the synthesis of the title compounds CH2CHDSO and CH2CD2SO and their characterization by infrared spectroscopy. The monodeuterated species occurs in two isotopically diastereomeric forms with the D atom either ci
THE rs STRUCTURES OF PROPYL FLUORIDE AND DIFFERENCES IN STRUCTURES BETWEEN ROTATIONAL ISOMERS
Hayashi, Michiro,Fujitake, Masaharu
, p. 9 - 24 (2007/10/02)
Microwave spectra of trans and gauche propyl fluoride and its isotopically substituted species have been measured.The rs structures of the trans and gauche isomers of this molecule are determined from the observed moments of inertia.It is found that the CCC angle values are largely different between two isomers, while the CCF angle values stay unchanged.The rs structures of ethyl fluorosilane and ethylmethyl sulfide are re-examined in order to compare the results with those of propyl fluoride.The differences in the structural parameter values between the rotational isomers are discussed for the present molecules and the analogous molecules such as ethanethiol and ethaneselenol.
