Figure 5. Four-dye and five-dye-branched dendrimer systems.

(a) Representative comparative spectral data for the fully assembled 2:1, 3:1, and 4:1 0.5 × R₀ dendrimer structures. Dye stoichiometries for dendrimer structures: 2:1=Cy3₈→Cy3.5₄→Cy5₂→Cy5.5₁; 3:1=Cy3₂₇→Cy3.5₃→Cy5₃→Cy5.5₁ and 4:1=Cy3₆₄→Cy3.5₁₆→Cy5₄→Cy5.5₁. Note: all data in a–c were normalized to the direct Cy5.5 emission. (b) Representative spectral data following the evolution of the five-dye 2:1 0.5 × R₀ dendrimer AF488₁₆→Cy3₈→Cy3.5₄→Cy5₂→Cy5.5₁ system. Constructs with dyes present and their corresponding colours are AF488 only (red), AF488→Cy3 (green), AF488→Cy5 (olive), AF488→Cy3 (navy) and AF488→Cy5.5 (pink). (c) Representative four-dye 0.5 × R₀ Cy3₈→Cy3.5₄→Cy5₂→Cy5.5₁ 2:1 dendrimer systems. Constructs with dyes present and their corresponding colours are Cy3 only (green), Cy3→Cy3.5 (navy), Cy3→Cy5 (pink) and Cy3→Cy5.5 (brown). The construct in c has the Cy3.5 ester dye replaced by a Cy3.5 phosphoramidite within the oligos. Inset in b,c shows the spectra of fully formed structure along with each of the contributing component dyes. Constructs with Cy3 as the initial dye were excited at 515 nm, while those with AF488 were excited at 465 nm.