Iron(II) and iron(III) complexes of 3,5-di-tert-butyl-o-benzoquinonemonooxime were synthesized and characterized by spectroscopic and electrochemical studies. Their ability to cleave DNA has been investigated under aerobic conditions at room temperature and in the presence and absence of H(2) O(2). The plasmid DNA pBR322 was effectively cleaved by these complexes in a concentration dependant manner.