Hetero-Selective DNA-Like Duplex Stabilized by Donor-Acceptor Interactions

We report on the characterization of a novel hetero‐selective DNA‐like duplex of pyrene and anthraquinone pseudo base pairs. The pyrene/anthraquinone pairs showed excellent selectivity in hetero‐recognition and even trimers were found to form a hetero‐duplex. Pyrene and anthraquinone moieties were tethered on acyclic D‐threoninol linkers and linked to adjacent residues by using standard phosphoramidite chemistry. When pyrene and anthraquinone were incorporated at pairing positions in complementary strands of natural DNA oligonucleotides, the duplex was stabilized significantly. Moreover, a pyrene hexamer and an anthraquinone hexamer formed a stable artificial hetero‐duplex without the assistance of natural base pairs. The pyrene/anthraquinone pair was so stable that even trimers formed a hetero‐duplex under conditions in which natural DNA strands of three residues do not. Artificial duplex: Electron‐rich pyrene and electron‐deficient anthraquinone moieties served as hetero‐selective pseudo base pairs within DNA duplexes (see figure; CT=Charge transfer). Furthermore, pyrene hexamer and anthraquinone hexamer units formed a unique artificial duplex by themselves. The pyrene/anthraquinone pair was so stable that even trimers formed an artificial duplex.