Characterization, nucleolytic, cytotoxic and antibacterial property of tetrakis(μ-4-chloro-2-nitrobenzoato-κ2O,O′)bis[aquacopper(II)], tetrakis(μ-2-chloro-6-fluorobenzoato-κ2O,O′)bis[aquacopper(II)] and tetrakis(μ-2-chlorobenzoato-κ2O,O′)bis[aquacopper(II

Three water soluble dicopper(II) complexes, tetrakis(μ-4-chloro-2-nitrobenzoato-κ2O,O′) bis[aquacopper(II)] (1), tetrakis(μ-2-chloro-6-fluorobenzoato-κ2O,O′)bis[aquacopper(II)] (2) and tetrakis(μ-2-chlorobenzoato-κ2O,O′)bis[aquacopper(II)] (3), have been synthesized. Complex 1 crystallizes in monoclinic system, space group C2/c with a = 28.813(3), b = 7.2368(6), c = 17.0053(14) Å, β = 105.395° and Z = 4, while 2 crystallizes in triclinic system, space group P1¯ with a = 7.5638(2), b = 13.0494(4), c = 16.7079(5) Å, α = 106.003°, β = 90.388°, γ = 91.855° and Z = 2. In addition, all the complexes have been characterized by their elemental analysis, FT-IR, UV–Vis spectroscopy and cyclic voltammetry. All complexes have been found to be redox active displaying two quasi-reversible redox couples corresponding to CuIICuII to CuIICuI and CuIICuI to CuICuI redox processes, respectively. The results from the gel electrophoresis experiment of 1–3 on pBR322 DNA, have demonstrated the occurrence of oxidative cleavage in the presence of hydrogen peroxide. The hydroxyl radical has been found to be the reactive oxygen species that is responsible for the cleavage reaction. In the antiproliferation tests against MCF-7, DU 145, HeLa and HepG2 cancer cell lines, all complexes show significant preference against HepG2 cell lines. All complexes also show significant preference against HepG2 cancer cells line over Chang human normal liver cells which means 1–3 are more potent against cancer cells than normal cells. In antibacterial tests against nine pathogenic bacterial species, all complexes show a very selective trend whereby they exhibit antibacterial activity against the Gram negative bacteria Enterobacter aerogenes.

The dimeric Cu(II) complexes are redox active and display two quasi-reversible redox behaviour corresponding to the CuIICuII to CuIICuI and CuIICuI to CuICuI redox process, respectively. Oxidative cleavage of pBr322 DNA occurs in the presence of hydrogen peroxide for which the hydroxyl radical is the reactive oxygen species that is responsible for the cleavage reaction.Figure optionsDownload as PowerPoint slide