Molecular structures of metal complexes with mefenamic acid

The infrared spectra of Na and Ca complexes of mefenamic acid were investig ated in the region between 4000 and 400 cm(-1). These spectra were compared with X-ray powder diffraction patterns of complexes. It is shown that the proposed structure for these complexes obtained from the infrared spectra w as supported by X-ray powder diffraction measurements. Bands due to v(as)(C OO)(-) and v(s)(COO)(-) stretching vibrations appear at about 1580 cm(-1) a nd in the range 1390-1400 cm (-1) in the infrared spectra of the samples, r espectively. The values of NH deformation vibrations do not change in the s pectra of mefenamic acid and its metal complexes. On the other hand, molecu lar mechanic calculations and conformational analysis of three compounds we re also established in the present work. As a result of these theoretical s tudies, the atomic planes and the peak assignments of the powder diffractio n patterns were determined. As a result of these experimental and theoretic al investigations, it may be concluded that metal atoms are connected to th e carboxyl group of the mefenamic acid. (C) 1999 Elsevier Science B.V. All rights reserved.