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  • 1
    Electronic Resource
    Electronic Resource
    Structure and fragmentations of [C3H7S]+ ionsPart II: for Part I, see Ref. 1. (1979)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1979), S. 36-45 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The principal fragmentation reactions of metastable [C3H7S]+ ions are loss of H2S and C2H4. These reactions and the preceding isomerizations of [C3H7S]+ ions with six different initial structures were studied by means of labelling with 13C or D. From the results it is concluded that the loss of H2S and C2H4 both occur at least mainly from ions with the structure [CH3CH2CH—SH]+ or from ions with the same carbon sulfur skeleton, with the exception of the ions with the initial structure [CH3CH2S—CH2]+, which partly lose C2H4 without a preceding isomerization. For all ions, more than one reaction route leads to [CH3CH2CH=SH]+. It is concluded that the loss of H2S is at least mainly a 1,3-elimination from the [CH3CH2CH=SH]+ ions. Both decomposition reactions are preceded by extensive but incomplete hydrogen exchange.
    Additional Material: 9 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210140111
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  • 2
    Electronic Resource
    Electronic Resource
    Rearrangements and fragmentations of [C2H5S]+ ions (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 13 (1978), S. 232-235 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [C2H5S]+ ions (m/e 61) with different initial structures were generated in the mass spectrometer from twelve precursor ions. Abundance ratios of competing metastable ion decompositions were used to determine whether these ions decompose through the same or different reaction channels. It was concluded that all [C2H5S]+ ions isomerize to a common structure or mixture of structures prior to decomposition in the first field free region. From 13C labelling experiments it was concluded that [C2H5S]+ ions generated from the molecular ions of 2-propanethiol-2-[13C], partially rearrange to a symmetrical structure before decomposition to [CHS]+ and CH4, whereas in [C2H5S]+ ions generated from the the molecular ions of 1,2-bis-(thiomethoxy-[13C]) ethane, the two carbon atoms become fully equivalent before CH4 loss occurs.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210130413
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  • 3
    Electronic Resource
    Electronic Resource
    Rearrangements and fragmentations of [C2H5S]+ ionsPart II: for Part I, see Ref. 1. (1979)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1979), S. 543-549 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: From deuterium labelling experiments it was concluded that metastable molecular ions of ethyl methyl sulfide lose a methyl radical with the formation of both [CH3S=CH2]+ amd [CH3CH=SH]+· The fragmentation reactions of metastable ions generated with these structure are losses of C2H2, H2S and CH4. These reactoins and the preceding isomerizations have also been studied by means of deuterium labelling. From the results it is concluded that the three fragmentation reactions most probably occur from ions with a C—C—S skeleton. Appearance energy measurements for ions generated with the two structures above and all give rise to the same ΔHf value for these three isomeric forms. Ab initio molecular orbitals calculations confirm that these three ions fortuitously have very similar heats of formation. A potential energy diagram rationalizing the isomerizations and the principal fragmentation reaction is presented.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210141006
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  • 4
    Electronic Resource
    Electronic Resource
    Potential energy profiles for the unimolecular reactions of [C3H7S]+ Ions (1980)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1980), S. 229-234 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Appearance energies were measured for several types of [C3H7S]+ ions. From these appearance energy values the heats of formation of the ions were calculated. For the isomeric ions that could not be generated in the mass spectrometer, the heats of formation were estimated by means of the isodesmic substitution method. Transition state energies for the decomposition to C2H4 and [CH3S]+ along two pathways were determined from the appearance energies of these ions. Using the energy values, potential energy diagrams were constructed for the rearrangements and decompositions of the [C3H7S]+ ions. A supplementary 13C Clabelling experiment is described for the determination of the rearrangement pathway of [CH3CH2CH=SH]+ ions prior to decomposition.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210150504
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  • 5
    Electronic Resource
    Electronic Resource
    Structure and fragmentation mechanism of [C3H7S]+ ions (1977)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 12 (1977), S. 326-329 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: From a comparison of the metastable ion bundance ratios for loss of C2H4 and H2S from [C3H7S]+ ions in a series of alkyl thio ethers and thiols it was concluded that in most compunds these ion s isomerize to a common structure prior to decomposition in the first field free region. The mechanism for C2H4 loss from the [C3H7S]+ ion gen erated from CH3SCH2CH3 was investigated in detail using 13C and 2H labelling. A rearrangement with formation of a cyclic intermediate prior to the decompistion reaction is proposed. The fragmentation is preceded by extensive hydrogen scrabling. The carbon atoms of the expelled C2H4 molecule are those of the CH2=CH3 moiety.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210120514
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