Synthesis and DNA studies of a copper(II) complex of 5,6-dihydro-5,6-epoxy-1,10-phenanthroline

A new copper(II) complex, Cu(epoxy)(phen)(NO₃)](NO₃)·H₂O (epoxy = 5,6-dihydro-5,6-epoxy-1,10-phenanthroline, phen = 1,10-phenanthroline), has been synthesized and characterized by elemental analysis, IR and UV–vis spectroscopy, and single crystal X-ray diffraction. The complex crystallized in a monoclinic system with space group P21/n, a = 13.3199(8) Å, b = 11.2917(7) Å, c = 16.0832(9) Å, α = 90°, β = 107.827(4)°, and γ = 90°. The complex cation possesses a distorted octahedral geometry, with Jahn–Teller distortion occurring in the CuN₄O₂ core. The binding interaction with calf thymus DNA (CT–DNA) was investigated by UV–vis and fluorescence spectroscopy, cyclic voltammetry, and viscometry. The results support a partially intercalative binding mode. Efficient cleavage of plasmid DNA by the complex was observed by gel electrophoresis.