Preparation of supramolecular chromophoric assemblies using a DNA duplex.

Organization of supramolecular assemblies of chromophores with precisely-controlled orientation and sequence remains challenging. Nucleic acids with complementary base sequences spontaneously form double-helical structures. Therefore, covalent attachment of chromophores to DNA or RNA can be used to control assembly and orientation of chromophores. In this perspective, we first review our recent work on the assemblies of fluorophores (pyrene and perylene) by using natural base pairs. The interaction between dyes can be strictly controlled by means of cluster and interstrand wedge motifs. We then discuss novel artificial base pairs that can suppress the interaction between fluorophores and nucleobases. We incorporated a cyclohexane moiety into DNA, and showed that these artificial base pairs suppressed the electron-hole transfer between fluorophores and nucleobases and enhanced the quantum yields of fluorophores. These base pairs can potentially be used to accumulate fluorophores inside DNA duplexes without decreasing quantum yields.