Rotational Spectra of Bicyclic Decanes: The Trans Conformation of (鈭?-Lupinine

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• 作者：Michaela K. Jahn ; David Dewald ; Montserrat Vallejo-L贸pez ; Emilio J. Cocinero ; Alberto Lesarri ; Jens-Uwe Grabow
• 刊名：Journal of Physical Chemistry A
• 出版年：2013
• 出版时间：December 19, 2013
• 年：2013
• 卷：117
• 期：50
• 页码：13673-13679
• 全文大小：291K
• 年卷期：v.117,no.50(December 19, 2013)
• ISSN：1520-5215

文摘

The conformational and structural properties of the bicyclic quinolizidine alkaloid (鈭?-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^鈥? 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鈥揌路路路N hydrogen bond to the electron lone pair at the nitrogen atom. Accurate rotational constants, centrifugal distortion corrections, and ¹⁴N 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.