Synthesis, structure, DNA-binding properties and cytotoxic activities of a new one-dimensional polymeric copper(II) complex with N-benzoate-N′-[3-(2-hydroxyl-ethylammino)propyl]oxamide as ligand

A new one-dimensional polymeric copper(II) complex, [Cu2(bhpox)(phen)]+n·nClO4−·nH2O, where bhpox3− and phen stand for N-benzoate-N′-[3-(2-hydroxyethylammino)propyl]oxamide and 1,10-phenanthroline, respectively, has been synthesized and characterized by elemental analysis, molar conductivity measurement, IR and electronic spectra studies, and single-crystal X-ray diffraction. The complex crystallizes in monoclinic space group P21/c with crystallographic data: a = 13.8500(2) Å, b = 13.3321(2) Å, c = 15.8532(2) Å, and Z = 4. In the crystal structure, the cation [Cu2(bhpox)(phen)]nn+ exhibits a one-dimensional zigzag-like structure for copper(II) ions alternately bridged by cis-oxamido and carboxylato groups, with the Cu⋯Cu separations of 5.1928(4) and 5.5240(5) Å, respectively. Each copper(II) ion is located in a slightly distorted square–pyramidal environment. Hydrogen bonds and π–π stacking interactions contribute to a three-dimensional supramolecular structure in the crystal. The interactions between the copper(II) complex and herring sperm DNA (HS-DNA) have been investigated by using electronic absorption titration, fluorescence titration, electrochemical titration and viscometry. All the experiments reveal that the copper(II) complex interacts with HS-DNA in the mode of intercalation with the intrinsic binding constant Kb = 2.67 × 104 M−1. The copper(II) complex exhibits potent anticancer activities against human hepatocellular carcinoma cell SMMC-7721 and human lung adenocarcinoma cell A549.