Details
| Original language | English |
|---|---|
| Pages (from-to) | 6076-6083 |
| Number of pages | 8 |
| Journal | Physical Chemistry Chemical Physics |
| Volume | 12 |
| Issue number | 23 |
| Publication status | Published - 2010 |
Abstract
The intrinsic conformational and structural properties of the tropinone azabicycle have been investigated in a supersonic jet expansion using rotational spectroscopy. The spectrum revealed the presence of equatorial and axial conformers originated by the inversion of the N-methyl group, with the tropane motif adopting a distorted chair configuration. The determination of substitution and effective structures for the two conformers reveals the flexibility and structural changes associated with the N-methyl inversion, mostly a flattening at the nitrogen atom and a simultaneous rising of the carbonyl group in the axial form. Relative intensity measurements indicate that the conformational equilibrium is displaced towards the equatorial form, with a relative population in the jet of Neq/Nax≈ 2/1, which would correspond to a relative energy of ca. 2 kJ mol-1 in pre-expansion conditions. Supporting ab initio calculations of the molecular properties and inversion barrier complemented the experimental work.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- General Physics and Astronomy
- Chemistry(all)
- Physical and Theoretical Chemistry
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In: Physical Chemistry Chemical Physics, Vol. 12, No. 23, 2010, p. 6076-6083.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - N-Methyl stereochemistry in tropinone
T2 - The conformational flexibility of the tropane motif
AU - Cocinero, Emilio J.
AU - Lesarri, Alberto
AU - Écija, Patricia
AU - Grabow, Jens Uwe
AU - Fernández, José A.
AU - Castaño, Fernando
PY - 2010
Y1 - 2010
N2 - The intrinsic conformational and structural properties of the tropinone azabicycle have been investigated in a supersonic jet expansion using rotational spectroscopy. The spectrum revealed the presence of equatorial and axial conformers originated by the inversion of the N-methyl group, with the tropane motif adopting a distorted chair configuration. The determination of substitution and effective structures for the two conformers reveals the flexibility and structural changes associated with the N-methyl inversion, mostly a flattening at the nitrogen atom and a simultaneous rising of the carbonyl group in the axial form. Relative intensity measurements indicate that the conformational equilibrium is displaced towards the equatorial form, with a relative population in the jet of Neq/Nax≈ 2/1, which would correspond to a relative energy of ca. 2 kJ mol-1 in pre-expansion conditions. Supporting ab initio calculations of the molecular properties and inversion barrier complemented the experimental work.
AB - The intrinsic conformational and structural properties of the tropinone azabicycle have been investigated in a supersonic jet expansion using rotational spectroscopy. The spectrum revealed the presence of equatorial and axial conformers originated by the inversion of the N-methyl group, with the tropane motif adopting a distorted chair configuration. The determination of substitution and effective structures for the two conformers reveals the flexibility and structural changes associated with the N-methyl inversion, mostly a flattening at the nitrogen atom and a simultaneous rising of the carbonyl group in the axial form. Relative intensity measurements indicate that the conformational equilibrium is displaced towards the equatorial form, with a relative population in the jet of Neq/Nax≈ 2/1, which would correspond to a relative energy of ca. 2 kJ mol-1 in pre-expansion conditions. Supporting ab initio calculations of the molecular properties and inversion barrier complemented the experimental work.
UR - http://www.scopus.com/inward/record.url?scp=77955959358&partnerID=8YFLogxK
U2 - 10.1039/c000528b
DO - 10.1039/c000528b
M3 - Article
C2 - 20405065
AN - SCOPUS:77955959358
VL - 12
SP - 6076
EP - 6083
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
SN - 1463-9076
IS - 23
ER -