Microwave Synthesis of a Rare [Ru₂L₃]⁴⁺ Triple Helicate and Its Interaction with DNA

A rare ruthenium(II) triple helicate of the type [Ru2L3]4+ (L=5,5′′′-dimethyl-2,2′:5′,5′′:2′′,2′′′-quaterpyridine) was synthesized in an unusually high yield by using microwave heating in ethylene glycol (see scheme). Efficient separation of the [Ru2L3]4+ helicate into its P and M isomers by DNA affinity chromatography indicated selective binding of P-[Ru2L3]4+ with various DNA sequences.