Mass spectral study of substituted allyl aryl and allyl alkyl selenides and some analogous sulfides

Prabhakar, S.; Krishna, Palakodety Radha; Kundu, Anupam; Roy, Sujit; Vairamani, M.

doi:10.1002/(sici)1097-0231(19990815)13:15<1564::aid-rcm674>3.0.co;2-#

Cited by 5 publications

(3 citation statements)

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“…Despite the interest in the selenium volatiles, very few reports are devoted to the investigation of mass spectral fragmentation of heavier dichalcogenidesdiselenides (R-SeSe-R) and selenosulfenates (R-SeS-R). Early mass spectrometric studies of organic selenium compounds were undertaken by Rebane [4 -6] and recently by Prabhakar et al [7]. However, diselenides and selenosulfenates were not a subject of interest in either of the studies.…”

mentioning

confidence: 99%

Interpretation of alkyl diselenide and selenosulfenate mass spectra

Meija

Beck

Caruso

2004

J. Am. Soc. Mass Spectrom.

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The mass spectral fragmentation of aliphatic diselenides and selenosulfenates is analyzed to gain a better understanding of the behavior of these species. The main fragmentation pathways of these species include the fragmentation along the Se™C bond, fragmentation along the Se™Se or Se™S bonds and intra-molecular rearrangements. In general, negative ionization favors the fragmentation along the Se™Se or Se™S bonds while positive ionization leads to stable molecular ions. Density functional theory calculations of bond dissociation energies and molecular orbital analysis was undertaken to explain the observed trends in molecular fragmentation. Besides the analysis of molecular fragmentation, a phenomenon of molecular association in negative electron impact and positive chemical ionization conditions was observed and investigated using a high resolution time-of-flight mass spectrometer. Molecular association that occurs during the ionization of species includes the formation of symmetrical diselenides from asymmetrical selenosulfenates and formation of alkylseleno adducts from the corresponding diselenides. For species which is hard to resolve by mass analysis, such as isobars of CHSe, CH 2 Se, and CH 3 Se, the isotope pattern superimposition procedure was applied to define the overlapping clusters. nterest in selenium species has recently increased because of their anti-oxidative and anti-carcinogenic properties. As a result, speciation of selenium metabolites in the environment has been undertaken by many research groups to gain more understanding about bio-transformations and the occurrence of the various selenium compounds. Inductively coupled plasma mass spectrometry (ICP-MS) is usually utilized for efficient detection and screening of the various selenium species at ultra-trace levels; however, the ultimate identification necessitates characterization by molecular mass spectrometry [1].Volatile selenium species are of interest as the end terminal in Se metabolism, and are emitted by plants as a means of self-detoxification [2]. Additionally, diselenides and selenosulfenates are red.-ox. active species and account for the anti-oxidative action of selenium [3]. Despite the interest in the selenium volatiles, very few reports are devoted to the investigation of mass spectral fragmentation of heavier dichalcogenidesdiselenides (R-SeSe-R) and selenosulfenates (R-SeS-R). Early mass spectrometric studies of organic selenium compounds were undertaken by Rebane [4 -6] and recently by Prabhakar et al. [7]. However, diselenides and selenosulfenates were not a subject of interest in either of the studies.In this study we analyzed the mass spectral fragmentation of methyl-, ethyl-and ethylmethyl-diselenides and selenosulfenates to gain a better understanding of the behavior of these species. In order to explain the fragmentation behavior of diselenides and selenosulfenates, density functional theory calculations were performed to obtain the bond dissociation energies and molecular orbital information. Experimental Reagen...

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mentioning

confidence: 99%

Interpretation of alkyl diselenide and selenosulfenate mass spectra

Meija

Beck

Caruso

2004

J. Am. Soc. Mass Spectrom.

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“…9 The characteristic ions observed at m/z 135, 122 and 117 correspond to [M À CH 3 ] , [M À C 2 H 4 ] Á and [M À SH] , respectively (Table 1). These ions are found to be dominant in the spectrum recorded at 20 eV.…”

Section: Allyl Phenyl Sulfide (2)mentioning

confidence: 99%

“…9 The formation of characteristic ions at m/z 183, 170 and 117 was explained by the losses of CH 3 Á , C 2 H 4 and SeH Á radical, respectively, from the molecular ion through a selenoClaisen rearrangement in the source of mass spectrometer. This mechanism was supported based on high resolution and CID studies.…”

Section: Allyl Phenyl Selenide (3)mentioning

confidence: 99%