Efficient Light-Harvesting Antennae Resulting from the Dense Organization of Dyes into DNA Junctions though d-Threoninol.

: Herein we report construction of efficient light-harvesting antennae by hybridization of DNA oligonucleotides containing extremely high densities of fluorophores into DNA junctions. Six pyrene donors could be incorporated into each arm without self-quenching using D-threoninol. A perylene acceptor was located at the center of the junction. Antenna effects of a duplex and three to eight-way junctions were systematically compared. Six- and eight-way junctions had the highest antenna effects and their effective absorption coefficients were 8.5 times higher than that of perylene. Interestingly, even-numbered junctions had higher efficiencies than odd-numbered junctions. Non-denaturing gel analyses and fluorescent lifetime measurements demonstrated that the strong odd-even effects were derived from differences in yields of junctions. The results presented will guide design of efficient artificial photosynthetic systems.