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  • 1
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1969), S. 1103-1115 
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The mass spectra of the alkyl cyanides up to n-pentyl cyanide were studied. Using metastablel ion transitions, appearance potentials and deuterium labelling, the fragmentation patterns, spectral characteristics and trends for this series can be given. The investigation of labelled compounds demonstrates the specificity of rearrangement and normal decomposition processes. Alkyl ions in nitriles are produced by simple cleavage of the carbon-carbon bond, while ions of the type [M -alkyl]+, which at the first sight could originate in the same way, are presumably formed via cyclic intermediates and are in fact rearrangement ions.Apart from the known γ and δ-hydrogen rearrangements, there is novel evidence for a β-hydrogen rearrangement via a five-membered ring transition state.
    Zusätzliches Material: 7 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The C8H9+-ion, formed from the molecular ions of 2-phenyl-1-bromoethane, 1-phenyl-1-bromoethane and of 1-phenyl-1-nitroethane by loss of the bromine atom and of the nitro group, splits off a molecule of acetylene after an almost complete randomization of hydrogens, as proved by deuteration. An eight-membered ring structure for the C8H9+-ion is proposed to explain these results.By loss of the nitro group from the molecular ions of 1-phenyl-1-nitropropane and of 1-phenyl-2-nitropropane the well-known phenylated cyclopropane ion3 (C9H11)+ is generated. Mass spectra of analogues, specifically deuterated in the side-chain, show that in this ion a randomization of hydrogen atoms in the cyclopropane ring as well as a hydride transfer from the cyclopropane ring to the phenyl cation occur.
    Zusätzliches Material: 17 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1968), S. 403-416 
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The mass spectral fragmentations of the saturated five-, six- and seven-membered ring ethers have been determined by studying their site-specifically deuterated analogues by both high and low-resolution mass spectrometry.The initial processes, governing the fragmentations of the cyclic ethers are shown to be identical with the well-known processes of linear nonbranched ethers, i.e. predominant α-fisson in the lower members and predominant carbon-oxygen fisson with charge retention on the carbon atom in the higher members.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Mass spectra of 1-phenylethanol-1 and its analogues, specifically deuterated in the aliphatic chain, suggest that the [M—CH3]+ ion is represented partly by an α-hydroxybenzyl fragment. Moreover, the molecular ion loses successively - after scrambling of all hydrogen atoms, except those of CH3—a hydrogen atom and C6H6, generation the CH3CO+ ion.Diffuse peaks, found in the spectra of of 2-phenylethanol-1 and its analogues, specifically deuterated in the aliphatic chain and in the phenyl ring, show that the molecular ion loses C2H4O, possibly via a four-center mechanism, after an exchange of aromatic and hydroxylic hydrogens.Mass spectra of 1-phenylpropanol-2 and its analogues, specifically, deuterated in the aliphatic chain, demonstrate that in the molecular ion exclusively the hydroxyl hydrogen atom is transferred to one of the ortho-positions of the phenyl ring via a McLafferty rearrangement, generating the [M — C2H4O]+ ion. Furtherore, an eight-membered ring structure is proposed for the [M — CH3]+ ion to explain the loss of H2O and C2H2O from this ion after an extensive scrambling of hydrogen atoms.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1968), S. 647-657 
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: This paper reports the monoisotopic mass spectra of the compounds (CH3)Ge—Ge(CH3)3,(C2H5)3Ge—Ge(C2H5)3 and (CH3)3Ge—Ge(C2H5)3. With the aid of metastable ion transitons and appearance potentials the fragmentation patterns can be given.The dominant reactions are explained in terms of the valence of the metal atom. According to the valence rule the possibility of forming an ion in which two germanium atoms are bonded to five other groups (alkyl or hydrogen) determines greatly the spectra, while successive elimination of the methyl groups appears to be difficult and elimination of the ethyl groups is a predominant process.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
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