Base-Selective DNA Cleavage with a Cyclometalated Palladium Complex

Abstract

The cyclometalated complex chloro(N,N,6C′)-2(2-methoxyphenyl)-1,10-phenanthroline palladium, 1, in the presence of H2O2, causes DNA strand scission at dG. The 5′ end of the resulting nick is a phosphate, while the 3′ end appears to be chemically heterogeneous, but is not a 3′-phosphate. Neither 1 alone, H2O2 alone, nor Li2PdCl4 plus H2O2 gives dG cleavage. Other cyclometalated palladium complexes, such as the one derived from azobenzene, showed no DNA nicking.