title: Rotational spectra of bicyclic decanes: the trans conformation of (-)-lupinine.
abstract: The conformational and structural properties of the bicyclic quinolizidine alkaloid (-)-lupinine have been investigated in a supersonic jet expansion using microwave spectroscopy. The rotational spectrum is consistent with a single dominant trans conformation within a double-chair skeleton, which is stabilized by more than 10.4 kJ mol(-1) with respect to other conformations. In the isolated conditions of the jet, the hydroxy methyl side chain of the molecule locks in to form an intramolecular O-H···N hydrogen bond to the electron lone pair at the nitrogen atom. Accurate rotational constants, centrifugal distortion corrections, and (14)N nuclear quadrupole coupling parameters are reported and compared to ab initio (MP2) and DFT (M06-2X) calculations. The stability of lupinine is further compared computationally with epilupinine and decaline in order to gauge the influence of intramolecular hydrogen bonding, absent in these molecules.
authors.affiliation: Institut für Physikalische Chemie & Elektrochemie, Lehrgebiet A, Gottfried-Wilhelm-Leibniz Universität , Callinstraße 3A, D-30167 Hannover, Germany.
authors.forename: Michaela K
authors.initials: MK
authors.lastname: Jahn
authors.forename: David
authors.initials: D
authors.lastname: Dewald
authors.forename: Montserrat
authors.initials: M
authors.lastname: Vallejo-López
authors.forename: Emilio J
authors.initials: EJ
authors.lastname: Cocinero
authors.forename: Alberto
authors.initials: A
authors.lastname: Lesarri
authors.forename: Jens-Uwe
authors.initials: JU
authors.lastname: Grabow
mesh_terms: D006860:Hydrogen Bonding; D008958:Models, Molecular; D008968:Molecular Conformation; D012399:Rotation; D013034:Sparteine / Q000031:analogs & derivatives* / Q000737:chemistry; D013237:Stereoisomerism; D000093843:Quinolizidine Alkaloids
chemical_list: D013034:Sparteine; C015971:lupinine; D000093843:Quinolizidine Alkaloids