Synthesis, DNA binding properties and electrochemistry towards an electrode-bound DNA of a novel anthracene–viologen conjugate

We have synthesized herein a novel molecular conjugate integrating an anthracene chromophore and a viologen moiety in the same molecular skeleton, joined together by a p-xylene spacer. This conjugate preserves both the DNA intercalative properties of the anthracene polycycle and the reversible electrochemical behavior of the viologen unit. The simultaneous presence of these components in one single molecular structure increases the affinity towards DNA in solution with respect to that observed for the isolated functional units, probably due to a co-operation of intercalative and electrostatic binding modes. The molecular conjugate interacts with both single and double-stranded DNA absorbed on ITO surfaces. It is shown that the presence of the anthracene unit plays a key role in increasing the affinity for the electrode-bound DNA also for the reduced, monocationic form of the conjugate. The application of the synthesized compound as an electroactive indicator able to discriminate between non-hybridized and hybridized surface-immobilized DNA has been investigated.