title: The broadband microwave spectra of the monoterpenoids thymol and carvacrol: conformational landscape and internal dynamics.
abstract: The rotational spectra of the monoterpenoids thymol and carvacrol are reported in the frequency range 2-8.5 GHz, obtained with broadband Fourier-transform microwave spectroscopy. For carvacrol four different conformations were identified in the cold conditions of the molecular jet, whereas only three conformations were observed for thymol. The rotational constants and other molecular parameters are reported and compared with quantum chemical calculations. For both molecules, line splittings due to methyl group internal rotation were observed and the resulting barrier heights could be determined. The experimental barrier heights, 4.0863(25) kJ/mol for trans-carvacrol-A, 4.4024(16) kJ/mol for trans-carvacrol-B, and 0.3699(11) kJ/mol for trans-thymol-A, are compared with similar molecules.
authors: Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany.
authors: D
authors: D
authors: Schmitz
authors: Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany.
authors: V A
authors: VA
authors: Shubert
authors: Center for Astrobiology, INTA-CSIC, Torrejón de Ardoz, Madrid, Spain.
authors: B M
authors: BM
authors: Giuliano
authors: Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany.
authors: M
authors: M
authors: Schnell
mesh_terms: D000081007:Cymenes; D006860:Hydrogen Bonding; D008872:Microwaves; D008958:Models, Molecular; D008968:Molecular Conformation; D039821:Monoterpenes / Q000737:chemistry*; D011789:Quantum Theory; D012399:Rotation; D013057:Spectrum Analysis; D013237:Stereoisomerism; D013943:Thymol / Q000737:chemistry*
chemical_list: D000081007:Cymenes; D039821:Monoterpenes; D013943:Thymol; C073316:carvacrol