Binding of bimetallic 1,10-phenanthroline ruthenium(II) complexes to DNA

The binding of [(phen)2RuII(Mebipy)-(CH2)n-(bipyMe)RuII(phen)2]4+ (Mebipy=4-methyl-2,2′-bipyridyl-4′-, n=5 2a, 7 2b or 10 2c) to double-stranded DNA is found to be sensitive to the linker chain length n and to show a DNA-induced stacking interaction at high binding concentrations (e.g. [Nu]/[Ru]=1).