Microwave spectrum and molecular structure of N-methoxyformamide

Styger, C.; Camináti, Walther; Ha, Tae–Kyu; Bauder, A.

doi:10.1016/0022-2852(91)90404-x

Cited by 12 publications

(6 citation statements)

References 8 publications

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“…The methoxy group deviates greatly from the molecular plane (dihedral angle D (CONC) = −92.9° in MO Z and −120.4° in MO E ). Both of these two calculated structures agree very well with the experimental data done by Styger et al When the hydrogen transfer proceeds the dihedral angle D (CONC) in each isomer (MO Z and MO E ) shifts from −92.9° → −89.4° → −83.5°, and −120.4° → −97.9° → −85.2°, respectively. Each methoxy group rotates along the CO axis toward the molecular plane only in some certain amount.…”

Section: Resultssupporting

confidence: 87%

Ab Initio Study of Substitution Effect and Catalytic Effect of Intramolecular Hydrogen Transfer of N-Substituted Formamides

Guo

1999

J. Phys. Chem. A

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Intramolecular hydrogen transfer of N-substituted formamides has been examined by ab initio theoretical calculation. The potential surfaces, the global isomeric structures, and the transition geometries of intramolecular hydrogen transfer were determined at the MP2/6-31+G** level of calculation. The energy was further analyzed by a single point calculation, MP2/6-311++G**//MP2/6-31+G**, and the use of G2 theory. There are E and Z conformations in each substituted derivative. The calculated energy barrier for the intramolecular hydrogen transfer (carbon−hydrogen to the carbonyl oxygen) of formamide is 76.14 kcal/mol. The Z form of N-substituted formamides (regardless of the type of substituents, CH3, OH, and OCH3) all have lower barriers; nevertheless, the E form counterparts show significant substitution effect. The methyl group decreases the barrier by 1.35 kcal/mol, while the hydroxy and methoxy groups increase the barriers by 2.40 and 1.69 kcal/mol, respectively. The catalytic effect achieved by the added H2O or NH3 molecule to the formamides is substantial. Energy barriers decrease around 26.5∼30.1 kcal/mol in most of the complexes and the transfer mechanism of each complex is concerted.

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Section: Resultssupporting

confidence: 87%

Ab Initio Study of Substitution Effect and Catalytic Effect of Intramolecular Hydrogen Transfer of N-Substituted Formamides

Guo

1999

J. Phys. Chem. A

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“…Planar "peptidic-like" structures of the OCOONHO moiety were found also in methylhydrazino carboxylate (4), N-methylformamide (5), and, recently, in acetanilide (6) through the studies of their MW spectra. The results obtained from the rotational spectrum and ab initio calculations of another simple derivative of formamide, Nmethoxyformamide, were reported a few years ago (7): in this case the OCOONHO group resulted nonplanar, the COONH dihedral angle being about 22°.…”

Section: Introductionmentioning

confidence: 80%

Free-Jet Rotational Spectrum and ab Initio Calculations of Formanilide

Ottaviani

Melandri

Maris

et al. 2001

Journal of Molecular Spectroscopy

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“…We could easily reproduce the observed splitting, the inertial defect, Á cc , and the changes of second moments of inertia, ÁP aa , ÁP bb and ÁP cc , in going from v ¼ 0 (2) cm À1 and e ¼ 34.7 (5) . The results of the fitting are summarized in table 6. In the flexible model calculations the coordinate has been considered in the AE70 range and solved into 41 mesh points [20].…”

Section: Barrier To Planarity For the Cis Formmentioning

confidence: 99%

“…The simplest molecule containing this group is formamide; its rotational spectrum was first interpreted, after some controversies in terms of a planar structure [1][2][3]. Planar 'peptidic-like' structures of the -CO-NH-moiety were found also in several other simple molecules [4][5][6][7]. In the case of N-methyl formamide a cis-trans conformational equilibrium has been observed [8,9].…”

Section: Introductionmentioning

confidence: 99%

Conformational equilibrium of formanilide: detection of the pure rotational spectrum of the tunnellingcisconformer

et al. 2005

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2005)Conformational equilibrium of formanilide: detection of the pure rotational spectrum of the tunnelling cis conformer, Formanilide has been investigated by molecular beam Fourier transform microwave spectroscopy. The rotational spectra of two conformers, with the formyl hydrogen cis or trans with respect to the phenyl group have been measured. Their relative energy has been estimated to be 350 AE 150 cm À1 , the trans form being more stable. In the cis species the plane of the pseudo-peptidic group forms an angle of AE34.7(5) (equilibrium value) with the ring. The two equivalent configurations, corresponding to the þ or -sign, are tunnelling through a barrier to planarity of 152(2) cm À1 .

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Microwave spectrum and molecular structure of N-methoxyformamide

Cited by 12 publications

References 8 publications

Ab Initio Study of Substitution Effect and Catalytic Effect of Intramolecular Hydrogen Transfer of N-Substituted Formamides

Ab Initio Study of Substitution Effect and Catalytic Effect of Intramolecular Hydrogen Transfer of N-Substituted Formamides

Free-Jet Rotational Spectrum and ab Initio Calculations of Formanilide

Conformational equilibrium of formanilide: detection of the pure rotational spectrum of the tunnellingcisconformer

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