title: The shape of ibuprofen in the gas phase.
abstract: Ibuprofen's pain-relieving properties arise from its ability to physically block the active site of an enzyme, thus making its structural and conformational properties highly interesting. We here present a conformer-selective high-resolution broadband rotational spectroscopy study of gas-phase ibuprofen. The interpretation of the spectroscopic results is supported by quantum-chemical calculations. We identify four low-energy conformers that differ in the structural arrangement of the isobutyl moiety with respect to the remainder of the molecule. While the isobutyl group shows high structural flexibility - resulting in distinct low-energy conformers - the propanoic acid group favors a stable arrangement.
authors.affiliation: Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany. melanie.schnell@mpsd.mpg.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Betz
authors.forename: Sabrina
authors.initials: S
authors.lastname: Zinn
authors.forename: Melanie
authors.initials: M
authors.lastname: Schnell
mesh_terms: D018712:Analgesics, Non-Narcotic / Q000737:chemistry*; D007052:Ibuprofen / Q000737:chemistry*; D008968:Molecular Conformation; D011789:Quantum Theory; D013816:Thermodynamics; D014835:Volatilization
chemical_list: D018712:Analgesics, Non-Narcotic; D007052:Ibuprofen