Molecular Structure of Propylene

Lide, David R.; Christensen, Daniel

doi:10.1063/1.1732055

Cited by 231 publications

(53 citation statements)

References 20 publications

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“…d~omputed using the experimental geometry given in ref. 43. e f~h e sum of the energies from a SCFISTO-3G computation on an isolation H atom (E = -0.466582 hartree) and for the ROHF-GVB (8) In our previous work it was shown that inexpensive GVB and MCSCF computations could yield reasonable potential energy curves and total dissociation energies that are within 20% of the best experimental values (25).…”

Section: Photochemical Reactions Ofmentioning

confidence: 90%

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Ab initio study of C—H bond breaking in olefins. II. GVB computations on propene ↔ H + cis- or trans-propen-1-yl

Maré¹,

Evleth²,

Poirier³

et al. 1994

Can. J. Chem.

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. Can. J. Chem. 72, 1230Chem. 72, (1994.The Generalized-Valence-Bond-Perfect-Pairing (GVB-PP) method has been used to investigate the structural behaviour, energy, and dipole moment along the reaction coordinates for propene tt H + cis-or trans-propen-1-yl. Geometry optimizations were carried out at the GVB(9)lSTO-3G level (complete valence shell) for the minimum energy propene structure (complete optimization) and for numerous structures up to r(C-H) = 10 A (only the elongated C-H distance kept fixed). The dissociation curves are smooth, without a maximum, and yield predicted dissociation energies of propene to H + cis-propen-1-yl and H + trans-propen-1-yl of 555.8 and 554.8 kJ mol-', respectively. These values are within several percent of those obtained for C-H bond rupture in ethylene using GVB and MCSCF methods with the same basis set. They are obviously too high but they confirm that removal of a hydrogen atom from the CH? moiety in propene requires about the same energy as removal of a hydrogen atom from ethylene. GVB(7)/6-31GllGVB(9)/STO-3G computations lower the predicted dissociation energies of propene + H + cis-propen-1-yl and H + trans-propen-1 -yl to 448.2 and 448.6 kJ mol-', respectively. The reduced energy concept (ER = (E, -E,)lDe) is applied to the reaction coordinates. Linear behaviour for In ER versus bond length is observed at long bond distances. At r(C-H) = 3 A, the values of the slopes, d(ln ER)ldr(C-H), which are related to the effective Morse constant B are -3.73 and -3.74 (GVB(9)lSTO-3G) and -2.75 and -2.8 1 (GVB(7)/6-3 1 GllGVB(9)lSTO-3G) for the H + cis-and H + trans-propen-1-yl reaction coordinates, respectively. On a utilisC la mCthode de l'appariement parfait de la liaison de valence gCnCraliste (GVB-PP) pour Ctudier le comportement structurel, 1'Cnergie et le moment dipolaire le long des coordonnCes de la rCaction propene tt H +cis-ou trans-propCn-1-yle. On a effectuC les optimisations de gtomCtrie au niveau GVB(9)lSTO-3G (couche de valence complete) pour la structure du propkne 2 Cnergie minimale (optimisation complkte) et pour de nombreuses structures jusqu'2 r(C-H) = 10 A (seule la distance C-H allongee est maintenue constante). Les courbes de dissociation sont lisses, sans un maximum, et elles conduisent 2 prCdire des Cnergies de dissociation pour les rCactions du propkne en H + cis-propen-1-yle et en H + trans-propCn-1-yle de 555,8 i t 554,8 kJ1 mol respectivement. Ces valeurs sont 2 1'intCrieur des limites de quelques pour-cent de celles obtenues pour la rupture de la liaison C-H dans 1'Cthylkne lorsque des calculs ont Cte effectuees par les mCthodes GVB et MCSCF, avec le mCme ensemble de base. Ces valeurs sont Cvidemment trop ClevCes, mais elles confirment que l'enlkvement d'un atome d'hydrogkne a partir de la portion CH, du propkne nCcessite approximativement la mCme Cnergie que l'enlkvement d'un atome d'hydrogkne a partir de 1'Cthylkne. Des calculs au niveau GVB(7)16-3 1GllGVB(9)lSTO-3G abaissent les valeurs des Cnergies de dissociation des rtactions du propkne en H + ...

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Section: Photochemical Reactions Ofmentioning

confidence: 90%

“…The experimental rs (substitution) structure, determined from the microwave spectra of seven isotopomers of 1 (43), is also given for comparison. As expected, the GVB(9)lSTO-3G optimized bond lengths are all longer than those obtained in a complete RHFISTO-3G optimization of 1.…”

Section: -Ylmentioning

confidence: 99%

Ab initio study of C—H bond breaking in olefins. II. GVB computations on propene ↔ H + cis- or trans-propen-1-yl

Maré¹,

Evleth²,

Poirier³

et al. 1994

Can. J. Chem.

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“…-Please order a reprint rather than making your own copy. The most probable structure of N-cis Lep-trans allylamine (NH2) was assumed in [5] to be a combination of that of methylamine [7] and that of propene [8], with the exception of the CCC angle (fixed to 126.1° as in butene-1 [9] and the CCC angle which was fitted to 117.6°. The actual increase with respect to the equivalent angle in methylamine (113°) was explained through the strong steric repulsion between the amine hydrogens and the allyl proton.…”

Section: Orientation Of the Total Dipole Momentmentioning

confidence: 99%

The Relative Orientation of the Total Dipole Moment in the N-cis Lone-Electron-Pair-Trans Isomer of Allylamine

Fischer

Botskor

1980

Zeitschrift Für Naturforschung A

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The dipole moment of the doubly deuterated species (CH2=CH-CH2-ND2) of N-cis Lone-electron-pair isomer of allylamine has been measured. The "isotope pulling elfect" has been used to determine the relative orientation of the total dipole moment with respect to the principal axes in the normal species. The possible effects of large amplitude motions on the observed effective dipole moments are discussed.

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“…Geometries used to calculate atomic coordinates were taken from gas phase electron diffraction results for ethylene (16) and trans-2-butene (17) and from microwave spectroscopy results for propylene (18) and cis-2-butene (19). Bond angle definition and equilibrium values of the bond angles are given in Table 1.…”

Section: Indo-mo Calculationsmentioning

confidence: 99%

Spectroscopic studies in olefins. VI. The valence angle dependence of interproton nuclear magnetic resonance coupling constants

Rummens¹,

Kaslander²

1976

Can. J. Chem.

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INDO–MO calculations have been performed for all the proton–proton coupling constants in ethylene, propylene, and cis- and trans-2-butene, both at their equilibrium geometry and at geometries deviating from equilibrium, thus resulting in [Formula: see text] parameters for all coupling constants as a function of all valence angles[Formula: see text]. It is shown that such valence angle effects can be appreciable, particularly for two- and three-bond couplings. The valence angle effects are demonstrated to be independent and additive. The calculated data, in combination with the exact geometrical data and experimental values for the coupling constants allow the separation of (inductive) substitution and rehybridization effects. It is also shown that for three-bond couplings the effects of in-path C—C—H bond angle changes are minor in comparison to the exo-path C=C—C valence angle effects. The new data provide a consistently good model to explain certain empirical trends in two- and three-bond coupling constants as a function of the size of the substituents, assuming a simple steric hindrance induced rehybridization mechanism. On the other hand it is also found that such a mechanism cannot account for similar trends in the H—C=C—CH3 allylic and the CH3—C=C—CH3 homoallylic coupling constants.

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Molecular Structure of Propylene

Cited by 231 publications

References 20 publications

Ab initio study of C—H bond breaking in olefins. II. GVB computations on propene ↔ H + cis- or trans-propen-1-yl

Ab initio study of C—H bond breaking in olefins. II. GVB computations on propene ↔ H + cis- or trans-propen-1-yl

The Relative Orientation of the Total Dipole Moment in the N-cis Lone-Electron-Pair-Trans Isomer of Allylamine

Spectroscopic studies in olefins. VI. The valence angle dependence of interproton nuclear magnetic resonance coupling constants

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