Self-Assemblies, Folding, and Properties of Perylene Monomers, Oligomers, and Polymers - Molecular Self-Assembly: Advances and Applications - page 188

folding and unfolding phenomenon, in which varying degrees of
electronic coupling between adjacent chromophores occurs.

Figure 5.23 Monomer, trimer, and hexamer structures are shown as

folded

-stacks and the trimer is used to manifest their
photoinduced dynamics. Spectra (a) through (e) are the
common single-molecule spectral shapes observed for
monomer (a

π

− − −

e). Portions
of spectral trajectories for a single trimer (f) and hexamer
(g) displaying dynamic emission color switches, indicating
folding, unfolding, and refolding. Twenty frames at 2 s
integration/spectrum =

b), trimer (a e), and hexamer (a

∼

40 s total elapsed time.

π−π

The range of spectra observed is an indicator of the range of

interaction between adjacent chromophores. Emission following
normal Franck

−

Condon progression (535, 575, and 625 nm, Fig.
5.23a) is attributed to the localized emission from individual free
perylene molecules, while vibronically resolved yellow (Fig. 5.23c)