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  • 1
    ISSN: 1573-1111
    Keywords: Force constant calculations ; n-alkanes ; mono-halo and di-halo alkanes ; urea inclusion compounds ; LAM-1 modes ; accordion vibrational modes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Force constants were determined for the C8, C10, C12 and C14 series ofn-alkanes C n H2n + 2 using an approximate SVFF calculation and observed LAM = 1 wave numbers. In this calculation the hydrogen atoms were neglected and only the carbon backbone chain and terminal atoms were considered; this was valid since only low-frequency vibrations were under consideration. Using force constant transfer, the wavenumbers of the LAM = 1 accordion modes for the analogous α-Cn H2n + 1 X and α,ω-Cn H2nX2 species, where X = C1, Br or I were calculated. For α-chloroalkanes and α,ω-dichloroalkanes, them = 1 accordion modes are calculated to be in the 220–130 cm−1 and 200–120 cm−1 regions, respectively. For the bromo- and iodo-analogues them = 1 accordion modes are calculated to be in the 200–100 cm−1, 150–90 cm−1 and in the 170–100, 135–80 cm−1 regions, respectively.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 911-923 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three commercial heparins of different molecular weights and anticoagulant activities were dinitrophenylated (DNP) with 2,4-dinitrofluorobenzene under aqueous conditions. The absorption spectra observed for DNP heparins in a 1% NaHCO3 solution consisted of the two absorption spectra characteristic of DNP - amino (N - DNP) and DNP - hydroxyl (O - DNP) groups. The number of N - DNP, O - DNP, and (N + O) - DNP groups were determined as well as the number of N - DNP groups per heparin chain; different values (i.e., 0.16, 0.17, and 0.55) for the latter were obtained with the three heparins. Further calculations showed that two of the heparins had approximately two (N + O) - DNP groups per chain (i.e., 2.1 and 1.8) whilst the third sample, considered to be a “cruder” heparin, had a value of 1.4.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 1497-1503 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three different commercial heparins were trinitophenylated with 2,4,6-trinitrobenzenesulfonic acid (TNBS) under aqueous conditions. The reaction kinetics of amino groups in heparin with TNBS showed that the reactivities of amino groups were significantly different for free amino groups on heparin, compared to reactivities in peptides and amino acid residues attached to heparin molecules. With TNBS, unreactive amino groups were always present during the reaction.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 2213-2224 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Measurements of surface tensions were carried out in the temperature range 25-120°C on seven different liquid polyisobutylenes with molecular weights ranging from 100 to 80,000. Relationships between the surface tenstion of polyisobutylene and other properties, such as the parachor, cohesive-energy density, and molecular weight are discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biospectroscopy 1 (1995), S. 29-36 
    ISSN: 1075-4261
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The FT-Raman vibrational spectrum of a child's deciduous exfoliated tooth has been analysed and the spectral features assigned to hydroxyapatite and protein. Comparisons made with older teeth from a Romano-British burial site (∼ 2k years) and fossilised animal teeth (∼ 1 M-70 M years) indicate that the organic protein component has disappeared with interment, whereas spectroscopic features due to the inorganic phosphatic matrix are common to all samples, modern and ancient. The application of the technique to the non-destructive analysis of archaeological samples and the recording of spectra from interred samples without detriment from fluorescent material is demonstrated. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 22 (1991), S. 607-611 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The pressure-broadening coefficients for the self-broadened S0(0), S0(1) and S0(2) pure rotational Raman lines of hydrogen and the S0(0) to S0(4) lines of deuterium were determined experimentally over the pressure range 1-100 bar and the temperature range 90-375 K. Broadening coefficients were also determined for the same lines in hydrogen and deuterium perturbed by helium, argon, oxygen, nitrogen, carbon monoxide and hydrogen chloride over the pressure range 2-100 bar, with a partial pressure of the host gas of 1 bar and a temperature of 293 K. In addition, the S0(0) pure rotational line of deuterium broadened by carbon monoxide and nitrogen was studied over the same pressure range and a temperature range of 100-293 K. The results are discussed and compared with those of previous studies in the literature.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 22 (1991), S. 613-618 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Raman spectra of the α-, β-, γ- and smectic polymorphs of isotactic polypropylene were recorded at 298 and 16.5 K. At 298 K the spectra of the polymorphs were very similar except in the antisymmetric C—H stretching region. However, at 16 K the Raman spectra of the polymorphs show different features in several wavenumber shift regions. Comparisons are made with infrared spectra recorded at 298 and 100 K and interpretations are made on the basis of non-equivalent sites in the monoclinic unit cells.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dissociation constants for an acetonitrile-zinc complex, (CH3CN)Zn2+, were measured in aqueous solutions containing zinc salts (40-80%, w/w) and acetonitrile by Raman spectroscopy. Quantitative measurements of the intensity of the free and complexed ν(CN) Raman bands at 2264 and 2320 cm-1, respectively, were used to determine the average enthalpy and entropy of the complex dissociation to free acetonitrile in the temperature range 293-343 K for a 70% (w/w) solution of zinc chloride (0.052 mol) in an aqueous solution containing acetonitrile (0.024 mol); δH° and δS° values of 8.4 ± 0.5 kJ mol-1, respectively, were determined.
    Additional Material: 6 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 23 (1992), S. 641-645 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Fourier transform (FT) Raman and infrared spectra of the outermost layer of human skin, the stratum corneum, were recorded. Assignments consistent with the FT Raman vibrations were made for the first time and compared with assignments from the FTIR spectrum. The results demonstrate that FT Raman spectroscopy holds several advantages over FTIR in studies of human skin. The molecular and conformational nature of human skin, and modifications induced by drug or chemical treatments, may be assessed by FT Raman spectroscopy.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The bands at 2485 and 940 cm-1 observed in the Raman spectra of 2,5-dimercapto-1,3,4-thiadiazole represent the hydrogen-bonded ν(SH) stretching and δ(C-SH) in-plane bending modes, respectively. A quantitative study of the hydrogen bonding was carried out using intensity measurements of the bands assigned to the hydrogen-bonded and the free δ(C-SH) in-plane deformations at 940 and 919 cm-1, respectively, as a function of temperature. The Fourier transform (FT) Raman spectra were recorded over the temperature range 303-403 K using an environmental chamber fitted into the FT Raman sample compartment. The equilibrium constants between the free and the hydrogen-bonded molecules were determined over this temperature range and the average enthalpy for hydrogen-bond formation was obtained (ΔH° = -3.35 ± 0.2 kJ mol-1).
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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