Semiexperimental Equilibrium Structures for the Equatorial Conformers of N-Methylpiperidone and Tropinone by the Mixed Estimation Method

Title:
Semiexperimental Equilibrium Structures for the Equatorial Conformers of N-Methylpiperidone and Tropinone by the Mixed Estimation Method
Authors:
Demaison, Jean; Craig, Norman C.; Cocinero, Emilio J.; Grabow, Jens-Uwe; Lesarri, Alberto; Rudolph, Heinz Dieter
Abstract:
N-Methylpiperidone (MPIP) and tropinone, which contain a structural motif found in numerous alkaloids, are too large to determine an accurate equilibrium structure either by ab initio methods or by experiment. However, the ground state rotational constants of the parent species and of all isotopologues with a substituted heavy atom (13C, 15N, 18O) are known from microwave spectroscopy. These constants have been corrected for the rovibrational contribution calculated from an ab initio cubic force field. These semiexperimental equilibrium rotational constants have been supplemented by carefully chosen structural parameters from medium level ab initio calculations. The two sets of data have been used in a weighted least-squares fit to determine reliable equilibrium structures for both molecules. This work shows that it is possible to determine reliable equilibrium structures for large molecules (34 degrees of freedom in the case of tropinone) at a detailed level of accuracy, and the method could be applied without too much difficulty to still larger molecules.
Citation:
Demaison, J., N.C. Craig, E.J. Cocinero, J-U. Grabow, A. Lesarri, and H.D. Rudolph. 2012. "Semiexperimental Equilibrium Structures for the Equatorial Conformers of N-Methylpiperidone and Tropinone by the Mixed Estimation Method." Journal of Physical Chemistry A 116(34): 8684-8692.
Publisher:
American Chemical Society
DATE ISSUED:
2012
Department:
Chemistry
Type:
Article
PUBLISHED VERSION:
10.1021/jp304178n
PERMANENT LINK:
http://hdl.handle.net/11282/334085

Full metadata record

DC FieldValue Language
dc.contributor.authorDemaison, Jeanen
dc.contributor.authorCraig, Norman C.en
dc.contributor.authorCocinero, Emilio J.en
dc.contributor.authorGrabow, Jens-Uween
dc.contributor.authorLesarri, Albertoen
dc.contributor.authorRudolph, Heinz Dieteren
dc.date.accessioned2014-11-10T14:13:37Z-
dc.date.available2014-11-10T14:13:37Z-
dc.date.issued2012en
dc.identifier.citationDemaison, J., N.C. Craig, E.J. Cocinero, J-U. Grabow, A. Lesarri, and H.D. Rudolph. 2012. "Semiexperimental Equilibrium Structures for the Equatorial Conformers of N-Methylpiperidone and Tropinone by the Mixed Estimation Method." Journal of Physical Chemistry A 116(34): 8684-8692.en
dc.identifier.issn1089-5639en
dc.identifier.urihttp://hdl.handle.net/11282/334085-
dc.description.abstractN-Methylpiperidone (MPIP) and tropinone, which contain a structural motif found in numerous alkaloids, are too large to determine an accurate equilibrium structure either by ab initio methods or by experiment. However, the ground state rotational constants of the parent species and of all isotopologues with a substituted heavy atom (13C, 15N, 18O) are known from microwave spectroscopy. These constants have been corrected for the rovibrational contribution calculated from an ab initio cubic force field. These semiexperimental equilibrium rotational constants have been supplemented by carefully chosen structural parameters from medium level ab initio calculations. The two sets of data have been used in a weighted least-squares fit to determine reliable equilibrium structures for both molecules. This work shows that it is possible to determine reliable equilibrium structures for large molecules (34 degrees of freedom in the case of tropinone) at a detailed level of accuracy, and the method could be applied without too much difficulty to still larger molecules.en
dc.language.isoen_USen
dc.publisherAmerican Chemical Societyen
dc.identifier.doi10.1021/jp304178nen
dc.subject.departmentChemistryen
dc.titleSemiexperimental Equilibrium Structures for the Equatorial Conformers of N-Methylpiperidone and Tropinone by the Mixed Estimation Methoden
dc.typeArticleen
dc.identifier.journalJournal of Physical Chemistry Aen
dc.identifier.volume116en
dc.identifier.issue34en
dc.identifier.startpage8684en
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