title: Raman and IR spectroscopic studies of fenamates--conformational differences in polymorphs of flufenamic acid, mefenamic acid and tolfenamic acid.
abstract: Solid-state Raman and IR spectra of two polymorphic forms of each of three fenamates (flufenamic acid, mefenamic acid and tolfenamic acid) display subtle but highly reproducible differences. Many of these spectral differences can be ascribed to different conformations of these molecules, involving two of four possible orientations of one substituted benzene ring with respect to the other. Interpretation of the vibrational spectra in terms of conformational differences has been facilitated by DFT calculations at the B3LYP/cc-pVDZ level for each conformer. The calculated spectra are compared with the experimental spectra in order to identify the conformers present in two polymorphic forms in each case, and detailed band assignments are obtained from the DFT calculations.
authors.affiliation: School of Science, University of Greenwich, Medway Campus, Chatham Maritime, Kent ME4 4TB, UK.
authors.forename: Saima
authors.initials: S
authors.lastname: Jabeen
authors.forename: Trevor J
authors.initials: TJ
authors.lastname: Dines
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Leharne
authors.forename: Babur Z
authors.initials: BZ
authors.lastname: Chowdhry
mesh_terms: D054361:Fenamates / Q000737:chemistry*; D005439:Flufenamic Acid / Q000737:chemistry; D008528:Mefenamic Acid / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D013816:Thermodynamics; D014732:Vibration; D062367:ortho-Aminobenzoates / Q000737:chemistry
chemical_list: D054361:Fenamates; D062367:ortho-Aminobenzoates; D008528:Mefenamic Acid; C009500:tolfenamic acid; D005439:Flufenamic Acid