Electron Diffraction Studies of Formaldehyde, Acetaldehyde and Acetone

Kato, Chuichi; Konaka, Shigehiro; Iijima, T.; Kimura, Masao

doi:10.1246/bcsj.42.2148

Cited by 85 publications

(17 citation statements)

References 25 publications

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“…Table 3 depicts the optimized geometries of eclipsed acetaldehyde, TS and syn and anti vinyl alcohol which were estimated by applying the same model chemistry. Apart from H1C1H3 and H4C2O angles which deviate by 1.27° and 2.47° respectively, our calculated bond lengths and angles of acetaldehyde are in satisfactory agreement with the experimental values [3,21]. For syn and anti vinyl alcohol, the average deviation between the observed [22,23] and computed parameters is 0.007 Å for the bond lengths and 0.56° for the bond angles.…”

Section: Resultssupporting

confidence: 82%

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Eclipsed Acetaldehyde as a Precursor for Producing Vinyl Alcohol

Osman¹,

Al‐Youbi²,

Elroby³

et al. 2012

IJMS

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The MP2 and DFT/B3LYP methods at 6-311++G(d,p) and aug-cc-pdz basis sets have been used to probe the origin of relative stability preference for eclipsed acetaldehyde over its bisected counterpart. A relative energy stability range of 1.02 to 1.20 kcal/mol, in favor of the eclipsed conformer, was found and discussed. An NBO study at these chemistry levels complemented these findings and assigned the eclipsed acetaldehyde preference mainly to the vicinal antiperiplanar hyperconjugative interactions. The tautomeric interconversion between the more stable eclipsed acetaldehyde and vinyl alcohol has been achieved through a four-membered ring transition state (TS). The obtained barrier heights and relative stabilities of eclipsed acetaldehyde and the two conformers of vinyl alchol at these model chemistries have been estimated and discussed.

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Section: Resultssupporting

confidence: 82%

“…The values between brackets are the experimental geometries of:bacetaldehyde taken from References [3,21];csyn vinyl alcohol taken from Reference [22] anddanti vinyl alcohol obtained from Reference [23]. …”

Section: Figurementioning

confidence: 99%

Eclipsed Acetaldehyde as a Precursor for Producing Vinyl Alcohol

Osman¹,

Al‐Youbi²,

Elroby³

et al. 2012

IJMS

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“…26 The experimental results agree quite well with the computed results presented here. Iijima 27 determined the zeropoint structure of acetone by reconciling the results of microwave and electron diffraction studies.…”

Section: Geometrysupporting

confidence: 87%

Hydrogen Bond Energies of Hydrogen Chloride−Carbonyl Complexes

et al. 1996

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Gas phase hydrogen bonding was studied via infrared spectroscopy in the following systems: methyl acetatehydrogen chloride, methyl formate-hydrogen chloride, 2-butanone-hydrogen chloride, and acetone-hydrogen chloride. The intensity of the H-Cl stretching vibration was monitored as a function of temperature, and the hydrogen bond energies and enthalpies were determined. The hydrogen bond energy for all four complexes was within 2.0 kJ mol -1 of -18.3 kJ mol -1 , indicating that the hydrogen bond energy is only minimally affected by nonlocal molecular structure. The acetone-hydrogen chloride complex was modeled by ab initio methods. The energy of formation of the complex, calculated at the MP2/6-311++G** level of theory, is -20.8 kJ mol -1 , in good agreement with the experiment.

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“…The previously synthesized [H(benzophenone) 2 ] + cation shows a similar O⋅⋅⋅O distance (2.470(3) Å) to [ 4 ‐H‐ 4 ] + , however, the O−H−O moiety is asymmetric in the crystal structure . Upon hemiprotonation of benzaldehyde, the C=O bond distance increases ([ 4 ‐H‐ 4 ] + 1.248(3) Å; 4 1.212(3) Å) and the C C=O −C bond length decreases ([ 4 ‐H‐ 4 ] + 1.441(4) Å) when compared to the reported structural data for 4 (1.479(4) Å) (Table ) . Geometry optimization reproduced the planar geometry of [ 4 ‐H‐ 4 ] + and the E ‐configuration of the C=O−H moiety; the hydrogen bridge is shown to be asymmetric in the gas phase, whereas the symmetric hydrogen bridge in the crystal structure is imposed by crystallographic symmetry.…”

Section: Methodsmentioning

confidence: 98%

Solid‐State Structure of Protonated Ketones and Aldehydes

2017

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Protonated carbonyl compounds have been invoked as intermediates in many acid-catalyzed organic reactions.T o gain key structural and electronic data about such intermediates,o xonium salts derived from five representative examples of ketones and aldehydes are synthesized in the solid state,and characterized by X-rayc rystallography and Raman spectroscopyfor the first time.DFT calculations were carried out on the cations in the gas phase.Whereas an equimolar reaction of the carbonyl compounds,a cetone,c yclopentanone,a damantanone,a nd acetaldehyde,w ith SbF 5 in anhydrous HF yielded mononuclear oxonium cations,t he same stoichiometry in areaction with benzaldehyde resulted in formation of ahemiprotonated, hydrogen-bridged dimeric cation. Hemiprotonated acetaldehyde was obtained when a2:1 ratio of aldehyde and SbF 5 was used. Experimental and NBO analyses quantify the significant increase in electrophilicity of the oxonium cations compared to that of the parent ketones/aldehydes.In targeted reactions,s alts of protonated ketones and aldehydes were isolated using stoichiometric amounts of Scheme 1. Resonance structures for protonated ketones.

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Electron Diffraction Studies of Formaldehyde, Acetaldehyde and Acetone

Cited by 85 publications

References 25 publications

Eclipsed Acetaldehyde as a Precursor for Producing Vinyl Alcohol

Eclipsed Acetaldehyde as a Precursor for Producing Vinyl Alcohol

Hydrogen Bond Energies of Hydrogen Chloride−Carbonyl Complexes

Solid‐State Structure of Protonated Ketones and Aldehydes

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