Details
| Original language | English |
|---|---|
| Pages (from-to) | 14084-14089 |
| Number of pages | 6 |
| Journal | Chemistry - a European journal |
| Volume | 20 |
| Issue number | 43 |
| Early online date | 5 Sept 2014 |
| Publication status | Published - 10 Oct 2014 |
Abstract
The conformational landscape and ring-puckering properties of ε-caprolactone have been analyzed by using microwave spectroscopy and quantum chemical calculations. Two conformers were detected in a supersonic jet expansion, the most stable form being a chair containing the ester group in its rectangular flap. This conformation benefits from reduced CH2 bond eclipsing and angle strain, while π-electron delocalization in the ester group is increased. The derived effective structure of the chair form satisfactorily agrees with the calculated near-equilibrium structure. A twist-boat conformer was also identified (9.4 kJ mol-1 higher in energy at CCSD(T)/aug-cc-pVTZ level), and was located in the boat-twist-boat pseudorotation cycle of the seven-membered ring. Three other low-energy conformers were investigated and characterized in terms of the four puckering coordinates of the seven-membered ring. Potential interconversions in the four-dimensional conformation space are also discussed. Twisting rings: The pseudorotation interconversion pathways of the seven-membered ring of ε-caprolactone have been studied by using microwave spectroscopy and theoretical methods based on Cremer-Pople ring-puckering coordinates. The molecule adopts two preferred chair and twist-boat conformations (see figure).
Keywords
- ab initio calculations, conformation analysis, lactones, medium-ring compounds, rotational spectroscopy
ASJC Scopus subject areas
- Chemical Engineering(all)
- Catalysis
- Chemistry(all)
- Organic Chemistry
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In: Chemistry - a European journal, Vol. 20, No. 43, 10.10.2014, p. 14084-14089.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Pseudorotational Landscape of Seven-Membered Rings
T2 - The Most Stable Chair and Twist-Boat Conformers of ε-Caprolactone
AU - Jahn, Michaela K.
AU - Dewald, David A.
AU - Vallejo-Lõpez, Montserrat
AU - Cocinero, Emilio J.
AU - Lesarri, Alberto
AU - Zou, Wenli
AU - Cremer, Dieter
AU - Grabow, Jens Uwe
PY - 2014/10/10
Y1 - 2014/10/10
N2 - The conformational landscape and ring-puckering properties of ε-caprolactone have been analyzed by using microwave spectroscopy and quantum chemical calculations. Two conformers were detected in a supersonic jet expansion, the most stable form being a chair containing the ester group in its rectangular flap. This conformation benefits from reduced CH2 bond eclipsing and angle strain, while π-electron delocalization in the ester group is increased. The derived effective structure of the chair form satisfactorily agrees with the calculated near-equilibrium structure. A twist-boat conformer was also identified (9.4 kJ mol-1 higher in energy at CCSD(T)/aug-cc-pVTZ level), and was located in the boat-twist-boat pseudorotation cycle of the seven-membered ring. Three other low-energy conformers were investigated and characterized in terms of the four puckering coordinates of the seven-membered ring. Potential interconversions in the four-dimensional conformation space are also discussed. Twisting rings: The pseudorotation interconversion pathways of the seven-membered ring of ε-caprolactone have been studied by using microwave spectroscopy and theoretical methods based on Cremer-Pople ring-puckering coordinates. The molecule adopts two preferred chair and twist-boat conformations (see figure).
AB - The conformational landscape and ring-puckering properties of ε-caprolactone have been analyzed by using microwave spectroscopy and quantum chemical calculations. Two conformers were detected in a supersonic jet expansion, the most stable form being a chair containing the ester group in its rectangular flap. This conformation benefits from reduced CH2 bond eclipsing and angle strain, while π-electron delocalization in the ester group is increased. The derived effective structure of the chair form satisfactorily agrees with the calculated near-equilibrium structure. A twist-boat conformer was also identified (9.4 kJ mol-1 higher in energy at CCSD(T)/aug-cc-pVTZ level), and was located in the boat-twist-boat pseudorotation cycle of the seven-membered ring. Three other low-energy conformers were investigated and characterized in terms of the four puckering coordinates of the seven-membered ring. Potential interconversions in the four-dimensional conformation space are also discussed. Twisting rings: The pseudorotation interconversion pathways of the seven-membered ring of ε-caprolactone have been studied by using microwave spectroscopy and theoretical methods based on Cremer-Pople ring-puckering coordinates. The molecule adopts two preferred chair and twist-boat conformations (see figure).
KW - ab initio calculations
KW - conformation analysis
KW - lactones
KW - medium-ring compounds
KW - rotational spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=84946776019&partnerID=8YFLogxK
U2 - 10.1002/chem.201403379
DO - 10.1002/chem.201403379
M3 - Article
AN - SCOPUS:84946776019
VL - 20
SP - 14084
EP - 14089
JO - Chemistry - a European journal
JF - Chemistry - a European journal
SN - 0947-6539
IS - 43
ER -