Chiral manganese (IV) complexes derived from Schiff base ligands: Synthesis, characterization, in vitro cytotoxicity and DNA/BSA interaction

Abstract

Two new couples of chiral manganese (IV) complexes with Schiff-base ligands, Λ-[Mn(R-L1)2]·2(CH3OH) (Λ-1) and Δ-[Mn(S-L1)2]·2(CH3OH) (Δ-1), Λ-[Mn(R-L2)2]·(H2O)2 (Λ-2) and Δ-[Mn(S-L2)2]·(H2O)2 (Δ-2), {H2L1=(R/S)-(±)-1-[(1-hydroxymethyl-propylimino)-methyl]-naphthalen-2-ol, H2L2=(R/S)-(±)-1-[(1-Hydroxymethyl-2-phenyl-ethylimino)-methyl]-naphthalen-2-ol} have been synthesized, and fully characterized by elemental analyses, UV–Vis spectrum, circular dichroism spectrum, FT-IR spectrum, mass spectrum, and single crystal X-ray diffraction (SXRD). The interaction of the four chiral Mn (IV) complexes with CT-DNA and BSA were also investigated by various spectroscopic techniques (UV–visible, fluorescence spectroscopic). The results show that the Δ-complexes exhibit more efficient CT-DNA interaction with respect to the Λ-complexes. All the complexes could quench the intrinsic fluorescence of BSA by a static quenching process. In addition, the vitro cytotoxicity of these complexes toward four kinds of cancerous cell lines (A549, HeLa, HL-60, and Caco-2) was assayed by the MTT method, which exhibited to be selectively active against certain cell lines.