Synthesis, characterization and DNA interaction studies of new complexes containing 2-mercaptobenzothiazole and different dinitrogen or phosphorous aromatic donors

The synthesis of new complexes of 2-mercaptobenzothiazole (Hmbt), [Zn(L)(mbt)(H2O)2]Cl, [M(mbt)(L)]Cl (M(II) = Pd, Pt; L = bpy, phen), [M(mbt)(PPh3)Cl] (M(II) = Pd, Pt), [Zn(PPh3)2(Hmbt)2Cl2], [Ru(mbt)2(H2O)2], [Ru(PPh3)2(mbt)2], [Ir(mbt)3]Cl, [OsO2(mbt)2], [Rh(mbt)3(H2O)3], [Ag(Hmbt)(mbt)] and [Au(mbt)2Cl], are reported. Their structures are discussed on the bases of spectroscopic [(IR, Raman, UV–Vis, NMR (1H, 13C and 31P) and mass)], elemental analysis, molar conductivity and thermal degradation measurements. The in vitro anticancer activity of Hmbt and its complexes, [Zn(L)(mbt)(H2O)2]Cl, [M(L)(Hmbt)]Cl (M(II) = Pd, Pt; L = bpy, phen) and [Ag(Hmbt)(mbt)], were evaluated against human breast cancer (MDA-MB231) and human ovarian cancer (OVCAR-8) cell lines. The CT-DNA-binding properties of [Zn(mbt)(phen)(H2O)2]Cl, [Pd(Hmbt)(phen)]Cl, [Pt(L)(Hmbt)]Cl (L = bpy, phen) and [Au(mbt)2Cl], were studied using circular dichroism (CD) spectroscopy. The CD spectral data are further supported by UV–Vis titrations of [Pt(phen)(mbt)]Cl, [Pd(phen)(mbt)]Cl and [Zn(mbt)(phen)(H2O)2]Cl with CT-DNA. The results indicate that the complexes may have intercalative CT-DNA binding capabilities.