Synthesis, characterization, DNA binding, cytotoxicity and molecular docking properties of Cu (II) and Mn (II) complexes with 1,4-bis (pyrazol-1-yl) terephthalic acid

Two novel complexes, [Cu (L)(H2O)]center dot H2O (1) and [Mn (H2O)(6)] center dot L center dot H2O (2) (L = 1,4-bis (pyrazol-1-yl) terephthalic acid), were synthesized under hydrothermal conditions. They were characterized using elemental analysis, infrared spectroscopy and single-crystal X-ray diffraction. Intramolecular weak interactions, such as hydrogen bonds, and intermolecular interactions play important roles in the construction of the complexes. The interaction of these complexes with fish sperm DNA (FS-DNA) was monitored and binding constants were determined using UV-visible spectroscopy, which revealed their ability to bind to FS-DNA, with binding constants for the two complexes of 1.88 x 10(4) M-1 (1) and 1.06 x 10(4) M-1 (2). Viscosity experiments further demonstrated the binding of the complexes to DNA. The complexes were further studied using gel electrophoresis assay with supercoiled plasmid pBR322 DNA. In addition, anticancer activities of the metal complexes investigated through MTT assays in vitro indicated good cytotoxic activity against cancer cell lines. Flow cytometry and apoptosis experiments showed that these complexes induced apoptosis of two different cancer cell lines (HeLa and KB cells), demonstrating a significant cancer cell inhibitory rate. Finally, a further molecular docking technique was employed to confirm the binding of the complexes towards the molecular target DNA.