Photoinduced DNA cleavage by benzenediradical equivalents: 1,3- and 1,4-bis(dicarbonylcyclopentadienyliron)benzene

Upon photolysis, diiron complexes 1,4- and l,3-Fp(2)C(6)H(4) (1 and 2) linearize plasmid DNA at ratios as low as 1.5 and 3.0 molecules/bp DNA, respectively. Additionally, single-strand cleavage was observed at ratios higher than 0.05 and 0.19 molecules/ bp DNA for 1 and 2, respectively. Radical scavenging studies and metal radical control experiments implicate carbon-centered radicals as participants in the cleavage pathway. (C) 2003 Elsevier Science Ltd. All rights reserved.