Synthesis, Characterization and Nuclease Activity of Ternary Copper(II) Complexes Containing Dipyrido[3,2-a:2′,3′-c]-phenazine and L-α-Amino Acids

Two new complexes: [Cu(dppz)(L-val)(H2O)]ClO4 (1) and [Cu(dppz)(L-tyr)(H2O)]ClO4 center dot 1.5H(2)O (2) (dppz= dipyrido[3,2-a:2', 3'-c]phenazine, L-val=L-valinate, L-tyr=L-tyrosinate) have been synthesized and investigated by elemental analysis, molar conductivity, UV-Vis and IR spectroscopies. Complex 1 has been structurally characterized by the single-crystal X-ray diffraction method, which crystallizes in the triclinic space group P-1 in a unit cell of a=0.9095(2) nm, b=1.3301(3) nm, c=1.3552(3) nm, alpha= 93.518(3)degrees, beta= 97.192(3)degrees, gamma= 106.361(3)degrees, V= 1.5526(6) nm(3), Z=2, D-c=1.598 g center dot cm (3), mu=0.849 mm(-1). The DNA binding and cleavage properties of the complexes have been studied by UV spectroscopy, fluorescence spectroscopy, viscosity measurement and agarose gel electrophoresis. The results show that the complexes can bind DNA by intercalation and cleave pBR322 DNA by free hydroxyl radical induced by the complexes in the presence of ascorbate, giving the order of the binding abilities and cleavage activity of the complexes to DNA: complex 2>1.