Enantiospecific palindromic recognition of 5'-d(CTCTAGAG)-3' by a novel rhodium intercalator: analogies to a DNA-binding protein

We are exploring principles of protein-DNA recognition through the design of model 9,10-phenanthrenequinonediimine (phi) complexes of rhodium(III) which bind site-selectively to DNA. [Rh(phi)] super(3+) complexes intercalate in the DNA major groove through the phi ligand and upon photoactivation promote strand scission via abstraction of the deoxyribose C3'-H atom. Here we report on the metal complex [Rh(DPB) sub(2)phi] super(3+) (DPB = 4,4'-diphenyl-2,2'-bipyridyl) (Figure 1), which mimics DNA-binding proteins in DNA site-specificity and affinity.