LAUSR

Abstract The synthesis of some new palladium(II), platinum(II) and silver(I) complexes based on (Δ)- and (Λ)-1,2–bis-(1H-benzimidazol-2-yl)-1,2-ethanediol (Δ-H2bie and Λ-H2bie) enantiomers in the absence and presence of the N,N-chelates 2,2′-bipyridyl and 9,10-phenanthroline, and triphenylphosphine is reported. The molecular structures of the new complexes are discussed on the basis of their IR, Raman, UV–Vis, NMR (1H, 13C and 31P) and mass spectra, elemental analyses, molar conductivities and TGA properties. Both Δ-H2bie and Λ-H2bie coordinate to the metal ions in a neutral bidentate manner through the azomethine-N and protonated hydroxy-O atoms, while in basic media, Δ-Hbie− and Λ-Hbie− are bound to the metal ions through the azomethine-N and deprotonated-O atoms as mono-negative bidentate chelating ligands. The in vitro anticancer activity of the complexes has been evaluated against the human breast cancer (MDA-MB231) and ovarian cancer (OVCAR-8) cell lines. The Δ-H2bie complexes are more active against the studied cell lines. The IC50 values for cell growth proliferation of [Ag(PPh3)(Λ-H2bie)]ClO4 and [Ag(PPh3)(Δ-Hbie)] are 0.443 and 1.277 μM, and 0.427 and 1.437 μM for the MDAMB231 and OVCAR-8 cell lines, respectively. The corresponding IC50 values for cisplatin were 3.20 (MDA-MB231) and 2.28 (OVCAR-8) μM. The DNA-binding properties of some of the complexes have been studied using circular dichroism (CD) spectroscopy. The results indicate that the complexes may have intercalative CT-DNA binding capabilities. The intercalation of the Δ-enantiomers appears to be greater than is that for the Λ-enantiomers. Insertion of the complexes into adjacent base pairs prevents neighboring base pairs from close stacking.