FT-IR and FT-Raman spectra of cimetidine and its metallocomplexes

We present vibrational spectra of three stable, well-reproducible, polymorphic forms of cimetidine (cim), a drug which is a powerful histamine Hz-receptor antagonist used in the treatment of peptic ulcer and the Zollinger-Ellison syndrome. Assignments of Raman and IR bands are made using semiempirical methods: MNDO, AM1 and PM3. We also describe the synthesis of Me(cim)(2)(ClO4)(2), where Me = Cu(ZI), Cd(II), Co(II) and Ni(LI), and present their vibrational data. We show that the obtained complexes are isostructural, however a metal ion that occupies a center of octahedral unit introduces some distortions that can be seen in the spectra, We also make tentative assignment of metal-ligand stretching modes observed in low frequency range. (C) 1999 Elsevier Science B.V. All rights reserved.