Exploring the conformational landscape of menthol, menthone, and isomenthone: A microwave study

• Main Authors: David eSchmitz, V. Alvin Shubert, Thomas eBetz, Melanie eSchnell
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2015-03-01
• Series: Frontiers in Chemistry
• Subjects: Chirality; molecular structure; terpeneoids; microwave spectroscopy; Conformational analysis
• Online Access: http://journal.frontiersin.org/Journal/10.3389/fchem.2015.00015/full

The rotational spectra of the monoterpenoids menthol, menthone, and isomenthone are reportedin the frequency range of 2−8.5GHz, obtained with broadband Fourier-transform microwave spectroscopy.For menthol only one conformation was identified under the cold conditions of the molecularjet, whereas three conformations were observed for menthone and one for isomenthone. Theconformational space of the different molecules was extensively studied using quantum chemicalcalculations, and the results were compared with molecular parameters obtained by the measurements.Finally, a computer program is presented, which was developed to automatically identifydifferent species in a dense broadband microwave spectrum using calculated ab initio rotationalconstants as input.