Selective DNA Strand Scission with Binuclear Copper Complexes: Implications for an Active Cu2-O2 Species

摘要

A homologous series of binuclear copper(II) complexes [Cu^II2(>Nn)(Y)2]²⁺ (>1–>3) (n = 3–5 and Y = (ClO4)⁻ or (NO3)⁻) were studied to investigate the intermediate(s) responsible for selective DNA strand scission in the presence of MPA/O2 (MPA = 3-mercaptopropanoic acid). While the >N3 complex does not react, the >N4 and >N5 analogues show comparable activity with strand scission occurring at a single-strand/double-strand junction. Identical reactivity is also observed in the alternate presence of H2O2. Spectroscopic and reactivity studies with [Cu^II2(>N4)(Y)2]²⁺ (>2) and H2O2 are consistent with DNA oxidation mediated by formation of a side-on peroxodicopper(II) (Cu2–O2) complex.