Lactone enol cation‐radicals: gas‐phase generation, structure, energetics, and reactivity of the ionized enol of butane‐4‐lactone

Tureček, František; Shetty, Vivekananda; Sadı́lek, Martin; Polášek, Miroslav

doi:10.1002/jms.342

Cited by 6 publications

(3 citation statements)

References 79 publications

(77 reference statements)

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“…Formation of other logical ion isomers, e.g., ␥-butyrolactone (2 ϩ⅐ ), the various distonic isomers of enol 6 ϩ⅐ [31], and open-chain isomers all-anti-(E,E)-1,4-dihydroxy-1,3-butadiene (7 ϩ⅐ ), and (2-hydroxy-1-ethyl) ketene (8 ϩ⅐ ), are still more endothermic ( Table 2).…”

Section: Precursor Ion Dissociationsmentioning

confidence: 98%

Modeling deoxyribose radicals by neutralization-reionization mass spectrometry. Part 1. Preparation, dissociations, and energetics of 2-hydroxyoxolan-2-yl radical, neutral isomers, and cations

Shetty

Sadı́lek

Chen

et al. 2004

J. Am. Soc. Mass Spectrom.

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Collisional neutralization of several isomeric C(4)H(7)O(2) cations is used to generate radicals that share some structural features with transient species that are thought to be produced by radiolysis of 2-deoxyribose. The title 2-hydroxyoxolan-2-yl radical (1) undergoes nearly complete dissociation when produced by femtosecond electron transfer from thermal organic electron donors dimethyl disulfide and N,N-dimethylaniline in the gas phase. Product analysis, isotope labeling ((2)H and (18)O), and potential energy surface mapping by ab initio calculations at the G2(MP2) and B3-PMP2 levels of theory and in combination with Rice-Ramsperger-Kassel-Marcus (RRKM) kinetic calculations are used to assign the major and some minor pathways for 1 dissociations. The major (approximately 90%) pathway is initiated by cleavage of the ring C-5[bond]O bond in 1 and proceeds to form ethylene and *CH(2)COOH as main products, whereas loss of a hydrogen atom forms 4-hexenoic acid as a minor product. Loss of the OH hydrogen atom forming butyrolactone (2, approximately 9%) and cleavage of the C-3[bond]C-4 bonds (<1%) in 1 are other minor pathways. The major source of excitation in 1 is by Franck-Condon effects that cause substantial differences between the adiabatic and vertical ionization of 1 (5.40 and 6.89 eV, respectively) and vertical recombination in the precursor ion 1(+) (4.46 eV). (+)NR(+) mass spectra distinguish radical 1 from isomeric radicals 2-oxo-(1H)oxolanium (3), 1,3-dioxan-2-yl (9), and 1,3-dioxan-4-yl (10) that were generated separately from their corresponding ion precursors.

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Section: Precursor Ion Dissociationsmentioning

confidence: 98%

Modeling deoxyribose radicals by neutralization-reionization mass spectrometry. Part 1. Preparation, dissociations, and energetics of 2-hydroxyoxolan-2-yl radical, neutral isomers, and cations

Shetty

Sadı́lek

Chen

et al. 2004

J. Am. Soc. Mass Spectrom.

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] The molecular ion of the less stable tautomer is often formed via mass spectrometric fragmentation of the corresponding parent compound (frequently through the McLafferty rearrangement). 11,14,16 Even if the tautomer formed is theoretically less stable than the other one, it does not isomerise to the more stable tautomer because gas-phase intramolecular tautomerisation usually involves a high energy barrier. Hence, the gas-phase chemistry of tautomers can be successfully studied by using mass spectrometric techniques.…”

Section: Introductionmentioning

confidence: 99%

Investigation of 4-(Nitrophenylamino)Pent-3-En-2-Ones and 4-(Nitrobenzylamino)Pent-3-en-2-Ones by Electron Ionization Mass Spectrometry. Observation of Characteristic Ortho Effects

Frański

Gierczyk

Fiedorow

et al. 2003

Eur J Mass Spectrom (Chichester)

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The compounds 4-(phenylamino)pent-3-en-2-ones (1-3) and 4-(benzylamino)pent-3-en-2-ones (4-6) substituted with a nitro group on the aromatic ring were studied by electron ionisation mass spectrometry (EIMS). It was deduced that the compounds 1-3 are converted into the tautomeric 4-(arylimino)pentan-2-one during the EI process. Mass spectrometric decompositions of ortho-substituted derivatives (1 and 4) were found to be different from those observed for meta- and para-isomers. The fragmentation pathways are discussed on the basis of data from linked B/E and B(2)/E scans, mass-analysed ion kinetic energy (MIKE) spectra, accurate mass measurements and isotope labelling.

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“…Several methods such as the composite chemical models, DFT and ab initio calculations have been used to estimate lactone basicity. − However, the number of works describing a systematic search for their intrinsic thermochemical parameters is still small. Verifying which method is the most suitable for investigating the stability of these molecules and their derivatives and the gas-phase reactivity is therefore crucial. − …”

mentioning

confidence: 99%

Evaluation of the Enthalpy of Formation, Proton Affinity, and Gas-Phase Basicity of γ-Butyrolactone and 2-Pyrrolidinone by Isodesmic Reactions

Vessecchi

Galembeck

2008

J. Phys. Chem. A

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The knowledge of thermochemical parameters such as the enthalpy of formation, gas-phase basicity, and proton affinity may be the key to understanding molecular reactivity. The obtention of these thermochemical parameters by theoretical chemical models may be advantageous when experimental measurements are difficult to accomplish. The development of ab initio composite models represents a major advance in the obtention of these thermochemical parameters, but these methods do not always lead to accurate values. Aiming at achieving a comparison between the ab initio models and the hybrid models based on the density functional theory (DFT), we have studied gamma-butyrolactone and 2-pyrrolidinone with a goal of obtaining high-quality thermochemical parameters using the composite chemical models G2, G2MP2, MP2, G3, CBS-Q, CBS-4, and CBS-QB3; the DFT methods B3LYP, B3P86, PW91PW91, mPW1PW, and B98; and the basis sets 6-31G(d), 6-31+G(d), 6-31G(d,p), 6-31+G(d,p), 6-31++G(d,p), 6-311G(d), 6-311+G(d), 6-311G(d,p), 6-311+G(d,p), 6-311++G(d,p), aug-cc-pVDZ, and aug-cc-pVTZ. Values obtained for the enthalpies of formation, proton affinity, and gas-phase basicity of the two target molecules were compared to the experimental data reported in the literature. The best results were achieved with the use of DFT models, and the B3LYP method led to the most accurate data.

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Lactone enol cation‐radicals: gas‐phase generation, structure, energetics, and reactivity of the ionized enol of butane‐4‐lactone

Cited by 6 publications

References 79 publications

Modeling deoxyribose radicals by neutralization-reionization mass spectrometry. Part 1. Preparation, dissociations, and energetics of 2-hydroxyoxolan-2-yl radical, neutral isomers, and cations

Modeling deoxyribose radicals by neutralization-reionization mass spectrometry. Part 1. Preparation, dissociations, and energetics of 2-hydroxyoxolan-2-yl radical, neutral isomers, and cations

Investigation of 4-(Nitrophenylamino)Pent-3-En-2-Ones and 4-(Nitrobenzylamino)Pent-3-en-2-Ones by Electron Ionization Mass Spectrometry. Observation of Characteristic Ortho Effects

Evaluation of the Enthalpy of Formation, Proton Affinity, and Gas-Phase Basicity of γ-Butyrolactone and 2-Pyrrolidinone by Isodesmic Reactions

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