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  • Chemistry  (15)
  • Computational Chemistry and Molecular Modeling  (6)
  • 1
    Electronic Resource
    Electronic Resource
    Enolization of the phosphoryl groupDedicated to Professor Dr. Rolf Appel on the occasion of his seventieth birthday. (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 2 (1991), S. 613-628 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enolization of the phosphoryl group has been studied where Y = PPh3, CN, Ts, COOEt, CONEt2; R and R′ = Et, Bu, Ph, EtO, BuO, PhO; and X = Cl, Br, ClO4, BF4. It has been established that substances with are phosphaenols, but in substances with Y = CONEt2 the phosphoryl group cannot be enolized under any conditions. Phosphaenolization is favored by a high acidifying ability of the Y group, the ability of the X anion to stabilize the phosphaenolic form due to formation of a hydrogen bond OH…X with the anion, and a low electronegativity of R and R′ groups. To evaluate the acidifying ability of Y, this article defines specific σ- constants dependent on the number of substituents at the α-carbon atom: σCH3-, σCH2- and σCH-. Their sums characterize the enolization ability of the phosphoryl group. The enolic structure in the solid state is possible if ∑CHn- 〉 2. If this sum lies in the range of 2 〈 ∑CHn- 〈 2.6 the phosphoryl-phosphaenol tautomerism can be expected in appropriate solutions. Acidic properties of the investigated compounds in MeNO2 and EtOH (absolute) have been determined. Calculations of the acidity of the phosphoryl CH forms (A) and of the phosphaenol OH forms (B) have been carried out.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hc.520020603
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  • 2
    Electronic Resource
    Electronic Resource
    The use of liquid chromatography/thermospray mass spectrometry with on-line ultraviolet diode array and radiochemical detection: Characterization of the putative metabolites of U-78875 in female rat faeces (1994)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 23 (1994), S. 1-5 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The metabolites of an anxiolytic drug candidate U-78875 {3-(5-cyclopropyl-1,2,4-oxadiazol-3-yl)-5-(1-methylethyl)-imidazo[1,5-α]quinoxalin-4(5H)-one; I} were investigated in female rat faecal extracts following a single oral dose of (14C)I. Initial metabolite profiling was performed by high-performance liquid chromatography incorporating homogeneous (i.e. liquid scintillant added post-column) radiochemical detection (radio-HPLC). This indicated the presence of parent drug and one minor metabolite. Because liquid scintillant is incompatible with thermospray interfaces, subsequent analysis by thermospray/HPLC/MS (TSP/LC/MS) incorporated radiochemical detection in heterogeneous (i.e. solid scintillant) mode and ultraviolet (UV) diode array detection. This revealed that the peak thought previously to be parent drug contained two components: a metabolite (major) and parent drug (minor). The UV spectrum and TSP/LC/MS/MS daughter ion analysis led to the proposition of a bisamide structure for the major metabolite. Chemical synthesis was used to confirm this structure. TSP/LC/MS indicated that the molecular weight of the minor metabolite was 16 u higher than the bisamide, suggesting an oxidized analogue. Attempts to obtain a daughter ion spectrum on this minor metabolite proved unsuccessful. On-line radiochemical and UV diode array detection greatly facilitates the TSP/LC/MS characterization of metabolites from studies using radiolabelled drugs.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200230102
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  • 3
    Electronic Resource
    Electronic Resource
    Relationship between microscopic and macroscopic structures of organic thin films for SHG (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 2 (1993), S. 245-268 
    Details
    ISSN: 1057-9257
    Keywords: Electron diffraction ; Non-linear optics ; Organic thin films ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: The experiments described in this paper were undertaken in order to obtain information about the relationship between the structure and non-linear optical properties (second-harmonic generation) of organic thin films. For this purpose, two closely related dyes, diones and tetrones, were compared, both of which are shown to have large hyperpolarisabilities. Their microscopic properties are investigated by conformational analysis and electron diffraction. It could be shown that detailed knowledge about the structure and the adjacent neighbour packing can be obtained from conformational analysis and electron diffraction in order to understand the non-linear optical properties of the two dyes.
    Additional Material: 21 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/amo.860020506
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  • 4
    Electronic Resource
    Electronic Resource
    Kinetics of contraction of drawn nylon 66 in aqueous phenol (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 427-436 
    Details
    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: The rate of contraction of drawn nylon 66 in aqueous phenol was investigated, and a method is described for correlating this contraction with a series of elementary rate processes. The rate constants so obtained were analyzed by absolute rate theory, and the variations of ΔH† and ΔS† with phenol concentration gave evidence of the nature of the reaction steps.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130303
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  • 5
    Electronic Resource
    Electronic Resource
    Role of hydrophobic bonding in the contraction of nylon 66 in phenolic solutions (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 1191-1199 
    Details
    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: Rate constants for intermolecular bond breaking (k1) and bond re-formation (k2) were calculated from contraction measurements. Variation of ΔH
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130608
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  • 6
    Electronic Resource
    Electronic Resource
    Relativistic quantum defect orbital calculations of singlet-singlet transitions in the zinc and cadmium isoelectronic sequences (1993)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 48 (1993), S. 385-397 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Relativistic quantum defect orbital (RQDO) calculations, with and without explicit account for corevalence correlation, have been performed on several electron transitions in the zinc and cadmium isoelectronic sequences, which are of interest in astrophysics and fusion plasma research. A comparative study with other theoretical results and experimental measurements has also been carried out. © 1993 John Wiley & Sons, Inc.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560480839
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  • 7
    Electronic Resource
    Electronic Resource
    Relativistic quantum defect calculations on the copper isoelectronic sequence (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 50 (1994), S. 411-428 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The quantum defect orbital (QDO) method and its relativistic (RQDO) counterpart have been employed in this work to compute oscillator strengths for several fine-structure transitions in members of the copper isoelectronic sequence up to Z = 92. The RQDO results are found to be in quite good agreement with the best estimates derived from other sources, whenever the comparison is possible. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560500605
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  • 8
    Electronic Resource
    Electronic Resource
    Quantum defect orbital study of electron transitions in rydberg molecules. I. Triatomic hydrogen (1993)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 48 (1993), S. 723-729 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Results of a pilot study on the applicability of the quantum defect orbital method for describing electronic transitions between molecular Rydberg states are reported. Oscillator strengths and Einstein emission coefficients for the triatomic hydrogen molecule have been calculated. The results are in good agreement with the data derived from more sophisticated theoretical approaches. © 1993 John Wiley & Sons, Inc.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560480864
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  • 9
    Electronic Resource
    Electronic Resource
    Fine-structure oscillator strengths for excited-state transitions in Cu-like ions (1992)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 44 (1992), S. 465-474 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transitions originating from excited states in copper-like ions have been studied. Fine-structure oscillator strengths obtained with both the quantum defect orbital (QDO) and its relativistic (RQDO) counterpart are reported for 4p 2P - nd 2D (n = 5, 6), 5p 2P - nd 2D (n = 5, 6), and np 2P - 6s 2S (n = 4, 5 ) absorption transitions. © 1992 John Wiley & Sons, Inc.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560440842
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  • 10
    Electronic Resource
    Electronic Resource
    Electronic transitions in the Rydberg radical H3O (1995)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 56 (1995), S. 631-638 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oscillator strengths and Einstein emission coefficients for electronic transitions in the Rydberg molecule H3O are reported. The calculations have been performed with the Quantum Defect Orbital (QDO) method, and the results are compared with those of an ab initio procedure. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560560869
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