[C2H4OS]&gt;·&gt;+&gt; Radical cations derived from alkyl thioformates: tandem mass spectrometry and molecular orbital calculations

Lahem, Driss; Flammang, Robert; Le, Hung M.; Nguyễn, Thanh Lâm; Nguyen, Minh Tho

doi:10.1039/a807814i

Cited by 4 publications

(5 citation statements)

References 18 publications

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“…The decarbonylation assumes the formation of a sulfurane ion as intermediate. A hydrogen-bridge complex is assumed to be involved in the β-distonic radical cation, as shown in Scheme . , For the title species, the (M – 28) + fragment was not observed in our spectra in either the valence or inner-shell region. Thus, decarbonylation events are precluded when hydrogen [HC(O)SCH 2 CH 3 ] is exchanged for a chlorine atom in ClC(O)SCH 2 CH 3 .…”

Section: Resultsmentioning

confidence: 87%

Outermost and Inner-Shell Electronic Properties of ClC(O)SCH₂CH₃ Studied Using HeI Photoelectron Spectroscopy and Synchrotron Radiation

et al. 2011

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A study of valence electronic properties of S-ethyl chlorothioformate (S-ethyl chloromethanethioate), ClC(O)SCH(2)CH(3), using HeI photoelectron spectra (PES) and synchrotron radiation is presented. Moreover, the photon impact excitation and dissociation dynamics of ClC(O)SCH(2)CH(3) excited at the S 2p and Cl 2p levels are elucidated by analyzing the total ion yield (TIY) spectra and time-of-flight mass spectra acquired in multicoincidence mode [photoelectron-photoion coincidence (PEPICO) and photoelectron-photoion-photoion coincidence (PEPIPICO)]. The HeI photoelectron spectrum is dominated by features associated with lone-pair electrons from the ClC(O)S- group, the HOMO at 9.84 eV being assigned to the n(π)(S) sulfur lone-pair orbital. Whereas the formation of C(2)H(5)(+) ion dominates the fragmentation in the valence energy region, the most abundant ion formed in both the S and Cl 2p energy ranges is C(2)H(3)(+). Comparison with related XC(O)SR (X = H, F, Cl and R = -CH(3), -C(2)H(5)) species reveals the impact of the alkyl chain on the photodissociation behavior of S-alkyl (halo)thioformates.

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Section: Resultsmentioning

confidence: 87%

Outermost and Inner-Shell Electronic Properties of ClC(O)SCH₂CH₃ Studied Using HeI Photoelectron Spectroscopy and Synchrotron Radiation

et al. 2011

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“…Additional motivation for the present work is in our continuing study of gas-phase species using a combination of mass spectrometry and quantum chemical calculations, in particular in the generation and characterization of unstable neutral species by mean of neutralization−reionization mass spectrometric (NRMS) techniques. − For this purpose, knowledge on the accurate energetics of both neutral and ionized states of the relevant species is crucial. In our earlier theoretical works, , the ionized DTFA was examined, but that study was mainly devoted to the 1,3-H shift mechanism in both ground and excited states.…”

Section: Introductionmentioning

confidence: 99%

“…For the sake of usefulness, a much more extended [CH 2 S 2 ] •+ energy surface has also been constructed here. In fact, knowledge of the [CH 2 OS] •+ energy surface has recently helped us to identify the HO−C−SH •+ /HO−C−SH pair of carbene upon dissociative ionization of alkylthioformates. , …”

Section: Introductionmentioning

confidence: 99%

“…In fact, knowledge of the [CH 2 OS] •+ energy surface has recently helped us to identify the HO-C-SH •+ /HO-C-SH pair of carbene upon dissociative ionization of alkylthioformates. 19,24 It is also well-known that carboxylic acids exist in the gas phase mainly in the dimeric form involving predominantly cyclic hydrogen-bonded structures. 25 To assess further the stability of such dimers in sulfur analogues, as well as their possible participation in the acid decomposition, different hydrogenbonded dimers of DTFA and DTHC have also been considered.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical Study of Dithioformic Acid, Dithiohydroxy Carbene and Their Radical Cations: Unimolecular and Assisted Rearrangements

Nguyen

Nguyễn

1999

J. Phys. Chem. A

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The potential energy surfaces of dithioformic acid and its functional isomer, dithiohydroxy carbene, in both neutral and ionized states have been investigated using ab initio molecular orbital calculations at both (U)MP2 and (U)QCISD(T) levels with the 6-31G(d,p) and 6-311++G(d,p) basis sets. The unimolecular decomposition of HC(S)SH giving H2 + CS2 and H2S + CS, its rearrangement to HS−C−SH, and different simple bond cleavages have been examined. In both electronic states, the carbene is a stable isomer lying in a relatively deep potential well. Formation of H2S via a one-step decomposition of acid is found to be favored over that of CS2 whose reaction path involves a carbene intermediate. Carbene radical cations also participate as crucial intermediates in unimolecular transformation of ionized acids. Calculations on different hydrogen-bonded dimers of acid and carbene suggest that, in the dimer form, while the carbene is not stable, elimination of both H2 and H2S is accelerated. The role of H2S and H2 as possible catalysts in the acid decomposition has also been investigated. H2S induces an efficient catalytic effect in different hydrogen transfer pathways. The standard heats of formation are estimated to be ΔH°f,298[HC(S)SH] = 113 ± 8 kJ/mol and ΔH°f,298[HS−C−SH] = 267 ± 12 kJ/mol based on CCSD(T)/6-311++G(3df,2p) calculations. Adiabatic ionization energies are predicted to be IEa(HS−C−SH) = 8.2 ± 0.3 eV and IEa(HC(S)SH)] = 9.0 ± 0.3 eV, and proton affinities are PA[HC(S)SH] = 802 ± 12 kJ/mol and PA[HS−C−SH] = 956 ± 12 kJ/mol.

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“…Flammang's group also used ion^molecule reactions to identify C 2 H 4 OS . radical cations that were generated by electron impact on alkyl thioformates 95 and radical cation isomers with the general formula [CH 3 O,C,N,S] . that were generated from various heterocyclic precursors.…”

mentioning

confidence: 99%

10 Gas phase organic ion–molecule reaction chemistry

Feng

Gronert

2000

Annu. Rep. Prog. Chem., Sect. B

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[C2H4OS]>·>+> Radical cations derived from alkyl thioformates: tandem mass spectrometry and molecular orbital calculations

Cited by 4 publications

References 18 publications

Outermost and Inner-Shell Electronic Properties of ClC(O)SCH₂CH₃ Studied Using HeI Photoelectron Spectroscopy and Synchrotron Radiation

Outermost and Inner-Shell Electronic Properties of ClC(O)SCH₂CH₃ Studied Using HeI Photoelectron Spectroscopy and Synchrotron Radiation

Theoretical Study of Dithioformic Acid, Dithiohydroxy Carbene and Their Radical Cations: Unimolecular and Assisted Rearrangements

10 Gas phase organic ion–molecule reaction chemistry

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[C2H4OS]>·>+> Radical cations derived from alkyl thioformates: tandem mass spectrometry and molecular orbital calculations

Cited by 4 publications

References 18 publications

Outermost and Inner-Shell Electronic Properties of ClC(O)SCH2CH3 Studied Using HeI Photoelectron Spectroscopy and Synchrotron Radiation

Outermost and Inner-Shell Electronic Properties of ClC(O)SCH2CH3 Studied Using HeI Photoelectron Spectroscopy and Synchrotron Radiation

Theoretical Study of Dithioformic Acid, Dithiohydroxy Carbene and Their Radical Cations: Unimolecular and Assisted Rearrangements

10 Gas phase organic ion–molecule reaction chemistry

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Outermost and Inner-Shell Electronic Properties of ClC(O)SCH₂CH₃ Studied Using HeI Photoelectron Spectroscopy and Synchrotron Radiation

Outermost and Inner-Shell Electronic Properties of ClC(O)SCH₂CH₃ Studied Using HeI Photoelectron Spectroscopy and Synchrotron Radiation