RAMAN-STUDY OF NEUTRAL PLATINUM-IMIDAZOLE COMPLEXES

The Raman spectra of recently synthesized cytotoxic neutral platinum(I I) and platinum(IV) complexes with N-alkylimidazole ligands were measu red and assigned. The bands both of imidazole ligands and of Pt-N and Pt-halogen functions were assigned by comparison the spectra of platin um complexes, their pure ligands, i.e. N-ethylimidazole and N-propylim idazole, and also cisplatin, K2PtCl4 and literature data. The largest changes in Raman band wavenumbers in bis(N-alkylimidazole)dihaloplatin um complexes were observed in the regions 150-350 and 350-450 cm(-1). The former region is characteristic of nu(Pt-X) bands, whereas the lat ter is assumed to relate to the nu(Pt-N) bands. The nu(Pt-X) band wave numbers depend mainly on the nature of anionic ligand X and in a small range on the neutral ligand. The intensity of the bands depends stron gly on the degree of covalent character of the bond. The nu(Pt-N) band wavenumbers depend mainly on the kind of neutral ligand and to some e xtent on the degree of covalent character of the anionic ligand. The b and at 255 cm(-1) in cisplatin was assigned to N-Pt-N bending and not to Pt-Cl stretching as assigned earlier. (C) 1997 by John Wiley & Sons , Ltd.