The vibrational spectra and structure of diketene and diketene-d4

Durig, J. R.; Willis, James N.

doi:10.1016/0371-1951(66)80035-8

Cited by 18 publications

(16 citation statements)

References 17 publications

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“…The infrared spectrum of a H 3 0 + ions were allowed to thermalize by collision before they sample of ketene vapor was recorded over a period of several entered the reaction region 106 cm further downstream. In days and was compared to those of the ketene monomer (21, this way we could avoid the introduction of ion types other 22) and dimer (23). Over the range of pressure and storage time than H30+ into the reaction region.…”

Section: Methodsmentioning

confidence: 99%

Gas-phase proton-transfer reactions of the hydronium ion at 298 K

Tanner¹,

Hopkinson²,

Mackay³

et al. 1979

Can. J. Chem.

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Rate constants measured with the flowing afterglow technique at 298 ± 2 K are reported for the proton-transfer reactions of H3O+ with CH2O, CH3CHO, (CH3)2CO, HCOOH, CH3COOH, HCOOCH3, CH3OH, C2H5OH, (CH3)2O, and CH2CO. Dissociative proton-transfer was observed only with CH3COOH. The rate constants are compared with the predictions of various theories for ion–molecule collisions. The protonation is discussed in terms of the energetics and mechanisms of various modes of dissociation.

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Section: Methodsmentioning

confidence: 99%

Gas-phase proton-transfer reactions of the hydronium ion at 298 K

Tanner¹,

Hopkinson²,

Mackay³

et al. 1979

Can. J. Chem.

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“…However, in vinylene carbonate the C=C frequency is at 1627 cm -1 which is only marginally greater than the value for cyclopentene [93]. Similarly the C=C frequencies of diketene [II,94] and of 3-methylene oxetane [95] are equal at 1693 cm - 1. Here the exocyclic methylene group is attached to a ring oxygen but the frequency is only 15 cm -1 higher than that of methylene cyclobutane.…”

Section: Oxygenated Ring Systemsmentioning

confidence: 97%

Alkenes and Vibrations of C=N and N=N Links

Bellamy¹

1980

The Infrared Spectra of Complex Molecules

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A good deal of new data has accumulated on the positions of C=C absorptions in different chemical environments, so that we are now in a better position to discuss the various factors which control the frequency shifts. But it is clear that, in this instance, both chemical and physical factors are important, and much remains to be done to determine the relative impacts of each. These two factors can be simply defined as follows. Chemical effects arise from alterations in the electron distribution within the bond which follow the replacement of one substituent by another. There is therefore a change in bond character which is reflected in an altered force constant and a shift in the vibrational frequency. However, the vibrational frequency can also be affected by factors such as substituent mass, bond-angle changes and vibrational coupling. These are purely physical effects, and they do not correspond to any change in the force constant of the bond, except insofar as angle changes may affect the hybridization. In many situations both types of effect are in operation. In conjugated systems, for example, the force constant of the bond is lowered as compared with the non-conjugated case, due to the delocalization of the 7t electrons. This leads to a shift to lower frequencit:s. However, there is now an increased possibility of vibrational coupling between the two C=C links, which will modify the frequency, although in itself it does not alter the force constants.Some of the most informative studies in this field have been those concerned with the effects of bond-angle changes and of ring strain, and these will therefore be considered first, as they illustrate very well the substantial impact of physical effects, and the difficulties which arise in disentangling them from the chemical effects which occur simultaneously.

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“…Interstellar ketene is postulated to be generated by the reaction of CO with CH 4 on dust-grain surfaces, and this proposal has been supported by laboratory experiments involving the UV laser photolysis of CO–CH 4 ices . If it were observed in the ISM, diketene ( 1 ) would represent the second molecule containing a four-membered ring and one of the larger organic species (10 atoms) detected. , Diketene ( 1 ) has been investigated by microwave spectroscopy up to 30 GHz, as well as by liquid-phase Raman , and by gas- and liquid-phase infrared spectroscopy. − The original microwave work of Mönnig et al determined the dipole moment via the Stark effect (μ a = 2.28 ± 0.02 D, μ b = 2.66 ± 0.02 D), and the rotational constants of diketene and also those of its two lowest energy vibrational satellites, ν 24 and 2ν 24 . Since 1967, however, the original microwave study has not been updated.…”

Section: Introductionmentioning

confidence: 97%

“…28 If it were observed in the ISM, diketene (1) would represent the second molecule containing a four-membered ring and one of the larger organic species (10 atoms) detected. 29,30 Diketene (1) has been investigated by microwave spectroscopy up to 30 GHz, 16 as well as by liquid-phase Raman 31,32 and by gas-and liquid-phase infrared spectroscopy. 31−35 The original microwave work of Monnig et al 16 determined the dipole moment via the Stark effect (μ a = 2.28 ± 0.02 D, μ b = 2.66 ± 0.02 D), and the rotational constants of diketene and also those of its two lowest energy vibrational satellites, ν 24 and 2ν 24 .…”

Section: ■ Introductionmentioning

confidence: 99%

Millimeter-Wave Spectroscopy, X-ray Crystal Structure, and Quantum Chemical Studies of Diketene: Resolving Ambiguities Concerning the Structure of the Ketene Dimer

et al. 2016

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The pure rotational spectrum of diketene has been studied in the millimeter-wave region from ∼240 to 360 GHz. For the ground vibrational state and five vibrationally excited satellites (ν, 2ν, 3ν, 4ν, and ν), the observed spectrum allowed for the measurement, assignment, and least-squares fitting a total of more than 10 000 distinct rotational transitions. In each case, the transitions were fit to single-state, complete or near-complete sextic centrifugally distorted rotor models to near experimental error limits using Kisiel's ASFIT. Additionally, we obtained less satisfactory least-squares fits to single-state centrifugally distorted rotor models for three additional vibrational states: ν + ν, ν, and 5ν. The structure of diketene was optimized at the CCSD(T)/ANO1 level, and the vibration-rotation interaction (α) values for each normal mode were determined with a CCSD(T)/ANO1 VPT2 anharmonic frequency calculation. These α values were helpful in identifying the previously unreported ν and ν fundamental states. We obtained a single-crystal X-ray structure of diketene at -173 °C. The bond distances are increased in precision by more than an order of magnitude compared to those in the 1958 X-ray crystal structure. The improved accuracy of the crystal structure geometry resolves the discrepancy between previous computational and experimental structures. The rotational transition frequencies provided herein should be useful for a millimeter-wave or terahertz search for diketene in the interstellar medium.

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The vibrational spectra and structure of diketene and diketene-d4

Cited by 18 publications

References 17 publications

Gas-phase proton-transfer reactions of the hydronium ion at 298 K

Gas-phase proton-transfer reactions of the hydronium ion at 298 K

Alkenes and Vibrations of C=N and N=N Links

Millimeter-Wave Spectroscopy, X-ray Crystal Structure, and Quantum Chemical Studies of Diketene: Resolving Ambiguities Concerning the Structure of the Ketene Dimer

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