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a
0
→
1
0.8
0.6
c
a
0
→
0
0
→
1
b
0
→
0
0.5
0.6
0.6
2
x
2
0
→
0
0.4
0
→
1
2A
0.4
0.3
0.4
1
0.2
0.2
0.2
2A
4A
0.1
1A
0.0
0.0
0.0
400
450
500
550
600
400
450
500
550
600
400
450
500
550
600
Wavelength (nm)
Wavelength (nm)
Wavelength (nm)
RO
O
S
S
O
O
O
O
P
O
O
O
RO
P
O
RO
O
HO
O
P
O
O
O
O
O
O
O
S
S
O
O
O
O
O
S
S
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
N
N
O
N
O
O
N
O
O
O
N
O
O
O
O
O
O
N
O
N
O
O
N
N
O
O
N
O
O
N
O
O
O
N
O
O
O
N
O
O
O
O
O
O
O
N
O
O
S
O
O
O
O
O
N
N
O
O
O
N
O
N
S
O
N
O
N
O
O
O
O
O
O
O
O
O
N
O
O
N
O
O
O
O
O
N
N
O
O
O
O
O
O
O
N
N
N
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
N
O
S
S
O
O
O
O
O
O
S
S
O
O
O
S
S
O
O
O
O
O
O
1A
O
1
2A
2A
2x2
O
RO
BzO
O
P
O
4
A
BzO
BzO
OH
OH
−
Figure 5.18
Comparing the UV
vis absorption spectra of linear foldable
monomer (
1A
), dimer (
2A
), and tetramer (
4A
) to those of
macrocyclic monomer
1
(a), macrocyclic dimer ring
2A
(b),
and dimer
−
dimer catenane
2
x
2
(c), respectively.
Both optical absorbance and NMR report the phenomena
of dynamic self-assemblies as the concentration increases (Fig.
5.19a,b); however, the variously twisted monomers are organizing
at distinct paces and the more highly twisted monomers assemble
at increasingly higher concentrations. At dilute concentrations, the
monomers remain mostly free and the observed physical properties
such as
→
→
| remain relatively
static over several orders of magnitude: no code behavior. Once
the concentration reaches the critical concentration that imparts
molecular codes dictated by the twist angle of perylene, a significant
percent of the monomers form stacked dimers, and the collective
behavior of molecular codes begin to emerge. At even higher
concentrations, longer stacks form, although the rate of change
in physical properties abates with successive assembled units.
The critical concentration onset covers a broad range (>2 orders
of magnitude) and hints at unique molecular codes, which can be
exploited to control reaction pathways.
r
= A
0
0
/A
0
1
or
∆
d
=|
d
−
d
obs
obs
obs
dil
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