Abstract
Four new metal complexes {M = Pd(II) or Pt(II)} containing the ligand 9-aminoacridine (9AA) were
prepared. The compounds were characterized by FT-IR and H1, C13, and P195t NMR spectroscopies. Crystal structure of the palladium complex of
formulae [Pd(9AA)(μ-Cl)]2·2DMF was determined by X-ray diffraction. Two 9-acridine molecules in the imine form bind
symmetrically to the metal ions in a bidentate fashion through the imine nitrogen atom and the C(1)
atom of the aminoacridine closing a new five-membered ring. By reaction with phosphine or pyridine,
the Cl bridges broke and compounds with general formulae [Pd(9AA)Cl(L)] (where L=PPh3 or py) were formed. A mononuclear complex of platinum of formulae [Pt(9AA)Cl(DMSO)] was
also obtained by direct reaction of 9-aminoacridine and the complex [PtCl2(DMSO)2]. The capacity of the compounds to modify the secondary and tertiary structures of DNA was
evaluated by means of circular dichroism and electrophoretic mobility. Both palladium and platinum
compounds proved active in the modification of both the secondary and tertiary DNA structures.
AFM images showed noticeable modifications of the morphology of the plasmid pBR322 DNA by the
compounds probably due to the intercalation of the complexes between base pairs of the DNA molecule.
Finally, the palladium complex was tested for antiproliferative activity against three different human
tumor cell lines. The results suggest that the palladium complex of formula [Pd(9AA)(μ-Cl)]2 has significant antiproliferative activity, although it is less active than cisplatin.