Narrow Results

Monolayers of thymine amphiphile containing azobenzene chromophore (Azo-Thy) were prepared on various aqueous oligonucleotide (dA₃₀, d(GA)₁₅, d(GGA)₁₀) subphases. Pressure–area isotherms and reflection absorption spectra of the monolayers on dA₃₀ or d(GA)₁₅ solution showed that the H-aggregate of the azobenzene units was formed at higher surface pressure than 25 mN/m. In contrast, the monolayer on an aqueous d(GGA)₁₀ solution did not form any aggregates of the azobenzene units even at high surface pressure. Base-pair formation between Azo-Thy and template d(GGA)₁₀ could give free volume to the azobenzene units in the monolayer to prevent the aggregation of the azobenzene units at the air–water interface.

In order to construct chromophores arrays that precisely controlled their arrangement, monolayers of an azobenzene bearing nucleoamphiphile were prepared on various oligoDNA solutions. Monolayers of the amphiphilic adenine derivative bearing an azobenzene moiety (C₁₂AzoC₅Ade) were prepared on thymidylic acid tetramer (dT4) and octamer (dT8) solutions, and UV-vis reflection absorption spectra of the monolayers were measured to investigate aggregation structures of the azobenzene. The absorption maximum of the monolayer was blue-shifted on the dT4 solution and red-shifted on the dT8 solution. It shows that azobenzene groups in the monolayer have parallel orientation (H aggregate) on the dT4 solution. Though, azobenzene groups have head-to-tail orientation (J aggregates) on the dT8 solution. When monolayers of C₁₂AzoC₅Ade were prepared on the synthesized cyclic oligonucleotides, the absorption spectra were totally different from those of the corresponding linear oligonucleotides.