School of Science, University of Greenwich, Medway Campus, Chatham Maritime, Kent ME4 4TB, UK.
Spectrochim Acta A Mol Biomol Spectrosc. 2012 Oct;96:972-85. doi: 10.1016/j.saa.2012.07.129. Epub 2012 Aug 10.
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.
三种芬那酸（氟芬那酸、甲芬那酸和托芬那酸）的每种两种多晶型体的固态拉曼和红外光谱显示出细微但高度可重现的差异。这些光谱差异中的许多可以归因于这些分子的不同构象，涉及四个可能的取代苯环相对于另一个苯环的两个方向。通过对每个构象体进行 B3LYP/cc-pVDZ 水平的 DFT 计算，有助于根据构象差异解释振动光谱。计算光谱与实验光谱进行比较，以确定每种情况下两种多晶型体中存在的构象体，并从 DFT 计算中获得详细的带分配。
