Self-Assemblies, Folding, and Properties of Perylene Monomers, Oligomers, and Polymers - Molecular Self-Assembly: Advances and Applications - page 167

− −

Figure 5.19 Concentration-dependent (a) A

0 0

/ A

0 1

ratio, r , and (b)

obs

NMR chemical shift,

d

, for compounds 1D

(

blue

)

, 1E (pink),

obs

1F at RT. Solid lines

display isodesmic model calculated values. Vertical dashed
lines mark the critical assembly concentrations. Insets show
the example concentration dependent spectra for compound
1D

(red), and 1H (green) in CHCl /CDCl

3 3

. (c) Calculated

∆ G

values scale nearly linearly with the

SA

dihedral twist angle

q

. (d) Perylene proton chemical shifts

in a 1:1:1 mixture (markers)
compared to the same shifts for separate homogeneous
solutions (lines) at equal concentrations. Nearly identical
values between the homogeneous and heterogeneous
solutions demonstrate almost exclusively independent
molecular codes. Insets show the 1 H NMR spectra for the
same mixture at four sample concentrations.

for compounds 1D , 1F , and 1H

Although the self-assembly free energy only differs by a few
kcal/mol (Fig. 5.19c), the tunable twisted monomers self-assemble
owing to their unique encoding, but even more remarkably multiple
codes are able to self-assemble simultaneously and independently.
To test code specificity, we made an equimolar 1:1:1 mixture of three
compounds: planar, dibromo, and tetrachloro perylene diimide to
compare the concentration-dependent in the heterogeneous

mixture to the individual homogeneous solutions (Fig. 5.19d).
Remarkably, the mixture self-organizes such that the differently
twisted monomers selectively self-assemble with their own kinds,
and apparently very little cross-assembly occurs. If the molecular

d

obs