Synthesis, Structure, and DNA Binding Studies of Copper(II) Complexes of Terpyridine Derivatives

Two copper(II) complexes, Cu(ttpy)22+1 and Cu(Brphtpy)22+2, were synthesized and characterized for their DNA binding and cleaving ability. The crystal structure of complex 1 reveals an axially compressed six-coordinate geometry around Cu(II). In spite of having an axially compressed geometry, the polycrystalline EPR spectrum of complex 1 at 298 K shows g|| > g⊥, indicating a dx2−y2 ground state for the Cu(II) complex. Both complexes 1 and 2 bind to CT DNA intercalatively with moderate binding strength (Kb = (8.4 ± 0.2) × 103 and (10.9 ± 0.2) × 104 M−1 (1 M = mol dm−3) respectively). Both of these complexes cleave plasmid DNA efficiently in the presence of peroxide.