Gel electrophoresis photograph of metal complexes. (a) Gel electrophoresis photograph showing the effects of metal complexes on pUC 19 DNA: lane 1, DNA + [Ni(L1)2]; lane 2, DNA + [Ni(L2)2]·H2O; lane 3, DNA + [Ni(L3)2]·H2O; lane 4, DNA + [Ni(L4)2]; lane 5, DNA + [Zn(L1)2]·H2O; lane 6, DNA + [Zn(L2)2]; lane 7, DNA + [Zn(L3)2]; lane 8, DNA + [Zn(L4)2]·H2O; lane 9, DNA + FeSO4; lane C, DNA alone. (b) Gel electrophoresis photograph showing the effects of metal complexes on pUC 19 DNA in the presence of H2O2: lane 1, DNA + [Ni(L1)2] + H2O2; lane 2, DNA + [Ni(L2)2]·H2O + H2O2; lane 3, DNA + [Ni(L3)2]·H2O + H2O2; lane 4, DNA + [Ni(L4)2] + H2O2; lane 5, DNA + [Zn(L1)2]·H2O + H2O2; lane 6, DNA + [Zn(L2)2] + H2O2; lane 7, DNA + [Zn(L3)2] + H2O2; lane 8, DNA + [Zn(L4)2]·H2O + H2O2; lane 9, DNA + FeSO4 + H2O2; lane C2, DNA + H2O2; lane C1, DNA alone.