Syntheses, characterization, DNA/HSA binding ability, and antitumor activities of a family of isostructural binuclear lanthanide complexes containing hydrazine Schiff base.

Three dinuclear lanthanide complexes, [Ln2 (L)2 (μ3 -OAc)4 (H2 O)2 ]⋅2H2 O (Ln = La (1), Eu (2) and Dy (3), HL = N'-(2-hydroxybenzylidene) nicotinohydrazide), have been synthesized and characterized by IR, elemental analysis, and X-ray single-crystal diffraction. Crystallographic study revealed the representative complex 1 display a discrete dinuclear structure with a distorted tricapped trigonal prismatic geometry around La(III) ion. The interaction of complexes 1-3 with CT-DNA was investigated by absorption spectra, fluorescence quenching and viscosity, which reveals the complexes binds to CT-DNA with a moderate intercalative mode. The complexes exhibited obvious DNA cleavage activities in the presence of H2 O2 . All complexes could bind to human serum albumin (HSA) with medium affinity through static mode thus HSA could effectively transport complexes. Furthermore, three complexes exhibited specific cytotoxicity to A549 cancer cells in micromole magnitude than other cancer cells tested, and less toxicity than cisplatin for normal human cells HUVEC, in which massive cell apoptosis was induced by complexes through producing DNA damage and suppressing DNA synthesis.