Synthesis and DNA interactions of pyridine-benzimidazole and saccharine-containing heteroleptic metal complexes

In this thesis, platinum(II) and palladium(II) sachharinate complexes with N-donor heterocyclic ligands have been synthesized and their interactions with DNA have been studied. The ligands, namely 2,6-bis(NH-benzimidazol-2-yl)pyridine (L1) and 2,6-bis(N-methyl-benzimidazol-2-yl)pyridine (L2) were synthesized from the precursor 2,6-dicarboxypyridine. The following platinum(II) and palladium(II) complexes were obtained from these ligands: tetra-saccharinatopalladium(II) [Pd(sac)4]K2 (1), trans-diaqua-disaccharinatoplatinum(II) trans-[Pt(sac)2(H2O)2](sacH) (2), saccharinato-2,6-bis(NH-benzimidazol-2-yl)pyridinepalladium(II) [Pd(L1)(sac)](sac)•5H2O (3), saccharinato-2,6-bis(NH-benzimidazol-2-yl)pyridineplatinum(II) [Pt(L1)(sac)](sac)•2,5H2O (4), saccharinato-2,6-bis(N-methyl-benzimidazol-2-yl)pyridinepalladium(II) [Pd(L2)(sac)](sac) (5) and saccharinato-2,6-bis(N-methyl-benzimidazol-2-yl)pyridineplatinum(II) [Pt(L2)(sac)](sac) (6), respectively. The Kb values obtained from the UV experiments are 0,08 × 105 M-1 (1); 0,26 × 105 M-1 (2); 2 × 105 M-1 (3); 3 × 105 M-1 (4); 2 × 105 M-1 (5); 3 × 105 M-1 (6) respectively. According to the experimental results, the Pt(II)-complexes bind to the DNA comparatively more stronger than the Pd(II)-complexes. In addition, the metal complexes derived from L1 ligand damaged to the DNA in lower concentration in comparison to those complexes derived from L2 ligand was observed. The interactions of the compounds with DNA were studied by UV-Vis titration, fluorescence, viscometer, gel-electrophoresis methods. The metal complexes were characterized by 1H-NMR, UV-Vis, FT-IR, ESI-MS and MALDI-TOF MS.