Syntheses, structures, DNA/BSA binding and cytotoxic activity studies of chiral alcohol-amine Schiff base manganese (II/III) complexes

Four new mixed-valence manganese complexes, [Mn(II)Mn(III)(2)(S-L-1)(2)(OAc)(4)]center dot 2H(2)O(1), [Mn(II) Mn(III)(2)(R-L-1)(2)(OAc)(4)]center dot 2H(2)O(2), [Mn(II)Mn(III)(2)(2H(2)O)(S-L-2)(2)(OAc)(4)] (3), [Mn(II)Mn(III)(2)(2H(2)O)(RL2)(2)(OAc)(4)] (4) [H2L1 derived from (R)/(S)-2-amino-1-butanol and 2-hydroxy-5-chlorobenzaldehyde, H2L2 derived from (R)/(S)-2-amino-3-phenyl-1-propanol and 2-hydroxy-4-methoxybenzaldehydel, were synthesized and fully characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction. Complexes 1-4 are mixed-valence trinuclear manganese compounds with six-coordinated. The linear Mn-III-Mn-II-Mn-III cores are triply bridged by acetate, phenolate and alkoxy groups. The vitro cytotoxicity test revealed that all complexes have substantial cytotoxic activity against three cancer cell lines (HepG2, MDA-MB-231 and A549). DNA-binding properties of 1-4 were investigated by UV-Vis, fluorescence spectroscopy, viscosity and thermal denaturation. All complexes bound to calf thymus DNA (CT-DNA) via an intercalative mode, and that derived from (S)-Schiff base ligands exhibited stronger interaction with DNA than (R)-isomers. Furthermore, the interactions of 1-4 with bovine serum albumins (BSA) in a static mode were also studied using absorption emission spectral techniques and molecular docking analysis. The chirality and structure of ligands showed to a large influence on the DNA/BSA binding ability and cytotoxicity of manganese complexes. The geometry optimization results are in agreement with experimental observations. (C) 2019 Elsevier B.V. All rights reserved.