Vibrational spectra and conformational behaviour of carbonyl isothiocyanates XCONCS, XF, Cl, Br, MeO, EtO, and acetyl isothiocyanate CH3CONCS

Campbell, Nicole; Gillis, Cyril J; Klapstein, Dieter; Nau, Werner M.; Balfour, Walter J.; Fougère, Scott G.

doi:10.1016/0584-8539(94)00199-l

Cited by 16 publications

(15 citation statements)

References 27 publications

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“…The gas phase and Ar-isolated IR spectra of ClC(O)NCS are consistent with the calculated anti / syn conformational equilibrium in the gas phase. The IR spectrum is characterized mainly by the ν as (NCS), ν(CO), ν(C–N) and ν as (ClCN) vibrational modes as was reported previously . Additionally, weak bands at 1633 cm –1 (ClC(O)SCN) and 1725 cm –1 (ClC(O)NCS) are observed in the IR spectrum of both constitutional isomers.…”

Section: Results and Discussionsupporting

confidence: 65%

“…The IR spectrum is characterized mainly by the ν as (NCS), ν(CO), ν(C−N) and ν as (ClCN) vibrational modes as was reported previously. 25 Additionally, weak bands at 1633 cm −1 (ClC(O)SCN) and 1725 cm −1 (ClC(O)NCS) are observed in the IR spectrum of both constitutional isomers. These bands are attributed to the first overtone of the antisymmetric stretching mode of the ClC(O)X (X = S, N) group.…”

Section: ■ Introductionmentioning

confidence: 96%

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Spectroscopic Characterization and Constitutional and Rotational Isomerism of ClC(O)SCN and ClC(O)NCS

et al. 2013

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Chlorocarbonylthio- and isothiocyanate (ClC(O)SCN and ClC(O)NCS) have been isolated and characterized by IR (Ar matrix, gas), Raman (liquid), (13)C NMR and UV-visible spectroscopies. Vibrational and quantum chemical studies suggest the presence of the syn and anti conformers (SCN group with respect to the C═O bond) in the gas phase for both constitutional isomers. syn-ClC(O)SCN is preferred by ΔH° (anti/syn) = 1.3(0.3) kcal mol(-1). The solid-state structure of ClC(O)SCN has been determined by single crystal X-ray diffraction analysis at low temperature. The crystalline solid consists exclusively of molecules in the syn conformation. On the other hand, the anti form is more stable for the ClC(O)NCS isomer. The structure of ClC(O)NCS and its conformational composition were determined by gas electron diffraction. An unusual low syn → anti interconversion energy barrier of 0.98 (0.15) kcal mol(-1) was detected for ClC(O)NCS at cryogenic temperatures. The photochemistry of both constitutional isomers isolated in solid argon at 15 K was studied. Rearrangement of ClC(O)SCN to ClC(O)NCS was observed in the neat liquid and under UV-vis irradiation of ClC(O)SCN isolated in solid argon. Properties have been discussed in terms of the valence electronic structure, including the analysis of the He(I) photoelectron spectrum of ClC(O)SCN.

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Section: Results and Discussionsupporting

confidence: 65%

Section: ■ Introductionmentioning

confidence: 96%

Spectroscopic Characterization and Constitutional and Rotational Isomerism of ClC(O)SCN and ClC(O)NCS

et al. 2013

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“…It is known that the ν(C=O) normal mode of carbonyl compounds is very sensitive to conformational properties. [20,21] As observed in Figure 5, two intense bands occur in the IR spectrum of FC(O)SSC(O)CF 2 Cl vapor at 1847 and 1771 cm -1 , whereas a third band of low intensity appears at 1827 cm -1 . The first two bands are assigned to the C=O stretching modes of the FC=O and CF 2 ClC=O groups in the most abundant (sp-sp) conformer.…”

Section: Vibrational Spectramentioning

confidence: 79%

Synthesis, Structure and Conformational Properties of Fluoroformylchlorodifluoroacetyl Disulfide, FC(O)SSC(O)CF₂Cl: Conformational Transferability in –C(O)SSC(O)– Compounds

et al. 2006

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“…It is well-known that the ν(C=O) normal mode of vibration is very sensitive regarding the conformational properties. 19,20 As is shown for the title species in the inset of the Figure 3, the carbonylic absorption is broad, with a maximum of the signal at 1806 cm -1 and a shoulder at 1824 cm -1 . The quantum chemical calculations allow assigning these modes to the gauche and anti conformers, respectively (see Table S1 and Figure S1 in the supporting information).…”

Section: Gas-phase Infrared Spectrummentioning

confidence: 93%

Photoexcitation, Photoionization, and Photofragmentantion of CF₃CF₂CF₂C(O)Cl Using Synchrotron Radiation between 13 and 720 eV

et al. 2015

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The main inner shell ionization edges of gaseous CF3CF2CF2C(O)Cl, including Cl 2p, C 1s, O 1s, and F 1s, have been measured in Total Ion Yield (TIY) mode by using tunable synchrotron radiation, and several resonance transitions have been assigned with the help of quantum chemical calculations. Interestingly, resonance transitions observed in the C 1s region can be assigned to different carbon atoms in the molecule according to the degree of fluorine substitution. Ionic photofragmentation processes have been studied by time-of-flight mass spectrometry in the Photoelectron-Photoion-Coincidence (PEPICO) and Photoelectron-Photoion-Photoion-Coincidence (PEPIPICO) modes. These techniques revealed a "memory-lost" effect especially around the C 1s region, since the fragmentation events are independent of the energy range considered. Moreover, different fragmentation mechanisms were inferred from these spectra in the valence (13.0-21.0 eV) as well as in the inner (180.0-750.0 eV) electronic energy regions. The vibrational spectral features of CF3CF2CF2C(O)Cl have been interpreted in terms of a conformational equilibrium between two conformations (gauche and anti of the CC single bond with respect to the CCl one) at room temperature, as determined from quantum chemical calculations and the detailed analysis of the infrared spectrum.

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Vibrational spectra and conformational behaviour of carbonyl isothiocyanates XCONCS, XF, Cl, Br, MeO, EtO, and acetyl isothiocyanate CH3CONCS

Cited by 16 publications

References 27 publications

Spectroscopic Characterization and Constitutional and Rotational Isomerism of ClC(O)SCN and ClC(O)NCS

Spectroscopic Characterization and Constitutional and Rotational Isomerism of ClC(O)SCN and ClC(O)NCS

Synthesis, Structure and Conformational Properties of Fluoroformylchlorodifluoroacetyl Disulfide, FC(O)SSC(O)CF₂Cl: Conformational Transferability in –C(O)SSC(O)– Compounds

Photoexcitation, Photoionization, and Photofragmentantion of CF₃CF₂CF₂C(O)Cl Using Synchrotron Radiation between 13 and 720 eV

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Vibrational spectra and conformational behaviour of carbonyl isothiocyanates XCONCS, XF, Cl, Br, MeO, EtO, and acetyl isothiocyanate CH3CONCS

Cited by 16 publications

References 27 publications

Spectroscopic Characterization and Constitutional and Rotational Isomerism of ClC(O)SCN and ClC(O)NCS

Spectroscopic Characterization and Constitutional and Rotational Isomerism of ClC(O)SCN and ClC(O)NCS

Synthesis, Structure and Conformational Properties of Fluoroformylchlorodifluoroacetyl Disulfide, FC(O)SSC(O)CF2Cl: Conformational Transferability in –C(O)SSC(O)– Compounds

Photoexcitation, Photoionization, and Photofragmentantion of CF3CF2CF2C(O)Cl Using Synchrotron Radiation between 13 and 720 eV

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Product

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Synthesis, Structure and Conformational Properties of Fluoroformylchlorodifluoroacetyl Disulfide, FC(O)SSC(O)CF₂Cl: Conformational Transferability in –C(O)SSC(O)– Compounds

Photoexcitation, Photoionization, and Photofragmentantion of CF₃CF₂CF₂C(O)Cl Using Synchrotron Radiation between 13 and 720 eV